Add VERBATIM to add_custom_target

implement pointer-to-member function_ref overloads

.drone.jsonnet

@@ -0,0 +1,275 @@
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+local library = "compat";
+
+local triggers =
+{
+    branch: [ "master", "develop", "feature/*" ]
+};
+
+local ubsan = { UBSAN: '1', UBSAN_OPTIONS: 'print_stacktrace=1' };
+local asan = { ASAN: '1' };
+
+local linux_pipeline(name, image, environment, packages = "", sources = [], arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "linux",
+        arch: arch
+    },
+    steps:
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'set -e',
+                'wget -O - https://apt.llvm.org/llvm-snapshot.gpg.key | apt-key add -',
+            ] +
+            (if sources != [] then [ ('apt-add-repository "' + source + '"') for source in sources ] else []) +
+            (if packages != "" then [ 'apt-get update', 'apt-get -y install ' + packages ] else []) +
+            [
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local macos_pipeline(name, environment, xcode_version = "12.2", osx_version = "catalina", arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "exec",
+    trigger: triggers,
+    platform: {
+        "os": "darwin",
+        "arch": arch
+    },
+    node: {
+        "os": osx_version
+    },
+    steps: [
+        {
+            name: "everything",
+            environment: environment + { "DEVELOPER_DIR": "/Applications/Xcode-" + xcode_version + ".app/Contents/Developer" },
+            commands:
+            [
+                'export LIBRARY=' + library,
+                './.drone/drone.sh',
+            ]
+        }
+    ]
+};
+
+local windows_pipeline(name, image, environment, arch = "amd64") =
+{
+    name: name,
+    kind: "pipeline",
+    type: "docker",
+    trigger: triggers,
+    platform:
+    {
+        os: "windows",
+        arch: arch
+    },
+    "steps":
+    [
+        {
+            name: "everything",
+            image: image,
+            environment: environment,
+            commands:
+            [
+                'cmd /C .drone\\\\drone.bat ' + library,
+            ]
+        }
+    ]
+};
+
+[
+    linux_pipeline(
+        "Linux 16.04 GCC 4.8 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.8', CXXSTD: '11', ADDRMD: '32,64' },
+        "g++-4.8-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 GCC 4.9 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-4.9', CXXSTD: '11', ADDRMD: '32,64' },
+        "g++-4.9-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 16.04 GCC 5* 32/64",
+        "cppalliance/droneubuntu1604:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 18.04 GCC 7* 32/64",
+        "cppalliance/droneubuntu1804:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17', ADDRMD: '32,64' },
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9 ARM64 UBSAN",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' } + ubsan,
+        arch="arm64",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9 ARM64 ASAN",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' } + asan,
+        arch="arm64",
+    ),
+
+    linux_pipeline(
+        "Linux 20.04 GCC 9 S390x UBSAN",
+        "cppalliance/droneubuntu2004:multiarch",
+        { TOOLSET: 'gcc', COMPILER: 'g++', CXXSTD: '11,14,17,2a' } + ubsan,
+        arch="s390x",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 GCC 12 32/64",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-12', CXXSTD: '11,14,17,20', ADDRMD: '32,64' },
+        "g++-12-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 GCC 13 32/64",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-13', CXXSTD: '11,14,17,20,2b', ADDRMD: '32,64' },
+        "g++-13-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 32 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '32' } + asan,
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 64 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '64' } + asan,
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 32 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '32' } + ubsan,
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 GCC 14 64 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'gcc', COMPILER: 'g++-14', CXXSTD: '11,14,17,20,2b', ADDRMD: '64' } + ubsan,
+        "g++-14-multilib",
+    ),
+
+    linux_pipeline(
+        "Linux 22.04 Clang 15",
+        "cppalliance/droneubuntu2204:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-15', CXXSTD: '11,14,17,20,2b' },
+        "clang-15",
+    ),
+
+    linux_pipeline(
+        "Linux 23.04 Clang 16",
+        "cppalliance/droneubuntu2304:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-16', CXXSTD: '11,14,17,20,2b' },
+        "clang-16",
+    ),
+
+    linux_pipeline(
+        "Linux 23.10 Clang 17 UBSAN",
+        "cppalliance/droneubuntu2310:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-17', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        "clang-17",
+    ),
+
+    linux_pipeline(
+        "Linux 23.10 Clang 17 ASAN",
+        "cppalliance/droneubuntu2310:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-17', CXXSTD: '11,14,17,20,2b' } + asan,
+        "clang-17",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 18 UBSAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        "clang-18",
+    ),
+
+    linux_pipeline(
+        "Linux 24.04 Clang 18 ASAN",
+        "cppalliance/droneubuntu2404:1",
+        { TOOLSET: 'clang', COMPILER: 'clang++-18', CXXSTD: '11,14,17,20,2b' } + asan,
+        "clang-18",
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,1z' } + ubsan,
+    ),
+
+    macos_pipeline(
+        "MacOS 10.15 Xcode 12.2 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,1z' } + asan,
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 UBSAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,17,20,2b' } + ubsan,
+        xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    macos_pipeline(
+        "MacOS 12.4 Xcode 13.4.1 ASAN",
+        { TOOLSET: 'clang', COMPILER: 'clang++', CXXSTD: '11,14,17,20,2b' } + asan,
+        xcode_version = "13.4.1", osx_version = "monterey", arch = "arm64",
+    ),
+
+    windows_pipeline(
+        "Windows VS2015 msvc-14.0",
+        "cppalliance/dronevs2015",
+        { TOOLSET: 'msvc-14.0', CXXSTD: '14,latest', B2_DONT_EMBED_MANIFEST: '1' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2017 msvc-14.1",
+        "cppalliance/dronevs2017",
+        { TOOLSET: 'msvc-14.1', CXXSTD: '14,17,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2019 msvc-14.2",
+        "cppalliance/dronevs2019",
+        { TOOLSET: 'msvc-14.2', CXXSTD: '14,17,20,latest' },
+    ),
+
+    windows_pipeline(
+        "Windows VS2022 msvc-14.3",
+        "cppalliance/dronevs2022:1",
+        { TOOLSET: 'msvc-14.3', CXXSTD: '14,17,20,latest' },
+    ),
+]

.drone/drone.bat

@@ -0,0 +1,25 @@
+@REM Copyright 2022 Peter Dimov
+@REM Distributed under the Boost Software License, Version 1.0.
+@REM https://www.boost.org/LICENSE_1_0.txt
+
+@ECHO ON
+
+set LIBRARY=%1
+set DRONE_BUILD_DIR=%CD%
+
+echo %DRONE_STAGE_MACHINE%
+
+set BOOST_BRANCH=develop
+if "%DRONE_BRANCH%" == "master" set BOOST_BRANCH=master
+cd ..
+git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+xcopy /s /e /q %DRONE_BUILD_DIR% libs\%LIBRARY%\
+python tools/boostdep/depinst/depinst.py %LIBRARY%
+cmd /c bootstrap
+b2 -d0 headers
+
+if not "%CXXSTD%" == "" set CXXSTD=cxxstd=%CXXSTD%
+if not "%ADDRMD%" == "" set ADDRMD=address-model=%ADDRMD%
+b2 -j3 libs/%LIBRARY%/test toolset=%TOOLSET% %CXXSTD% %ADDRMD% variant=debug,release embed-manifest-via=linker

.drone/drone.sh

@@ -0,0 +1,31 @@
+#!/bin/bash
+
+# Copyright 2022 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+set -ex
+export PATH=~/.local/bin:/usr/local/bin:$PATH
+
+uname -a
+echo $DRONE_STAGE_MACHINE
+command -v lscpu && lscpu
+
+DRONE_BUILD_DIR=$(pwd)
+
+BOOST_BRANCH=develop
+if [ "$DRONE_BRANCH" = "master" ]; then BOOST_BRANCH=master; fi
+
+cd ..
+git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git boost-root
+cd boost-root
+git submodule update --init tools/boostdep
+cp -r $DRONE_BUILD_DIR/* libs/$LIBRARY
+python tools/boostdep/depinst/depinst.py $LIBRARY
+CXXFLAGS= ./bootstrap.sh
+./b2 -d0 headers
+
+echo "using $TOOLSET : : $COMPILER ;" > ~/user-config.jam
+./b2 -j2 libs/$LIBRARY/test toolset=$TOOLSET cxxstd=$CXXSTD variant=debug,release \
+  ${ADDRMD:+address-model=$ADDRMD} ${CXXFLAGS:+cxxflags=$CXXFLAGS} ${LINKFLAGS:+linkflags=$LINKFLAGS} \
+  ${UBSAN:+undefined-sanitizer=norecover debug-symbols=on} ${ASAN:+address-sanitizer=norecover debug-symbols=on}

.github/workflows/ci.yml

@@ -19,18 +19,23 @@ jobs:
         include:
           - toolset: gcc-4.8
             cxxstd: "03,11"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-4.8
+          - toolset: gcc-4.9
+            cxxstd: "03,11"
+            container: ubuntu:16.04
+            os: ubuntu-latest
+            install: g++-4.9
           - toolset: gcc-5
             cxxstd: "03,11,14,1z"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-5
           - toolset: gcc-6
             cxxstd: "03,11,14,1z"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: g++-6
           - toolset: gcc-7
             cxxstd: "03,11,14,17"
@@ -49,34 +54,38 @@ jobs:
             install: g++-10
           - toolset: gcc-11
             cxxstd: "03,11,14,17,2a"
-            os: ubuntu-20.04
-            install: g++-11
+            os: ubuntu-22.04
           - toolset: gcc-12
             cxxstd: "03,11,14,17,20,2b"
             os: ubuntu-22.04
             install: g++-12
           - toolset: gcc-13
             cxxstd: "03,11,14,17,20,2b"
-            os: ubuntu-latest
             container: ubuntu:23.04
+            os: ubuntu-latest
             install: g++-13
+          - toolset: gcc-14
+            cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: g++-14
           - toolset: clang
             compiler: clang++-3.9
             cxxstd: "03,11,14"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-3.9
           - toolset: clang
             compiler: clang++-4.0
             cxxstd: "03,11,14"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-4.0
           - toolset: clang
             compiler: clang++-5.0
             cxxstd: "03,11,14,1z"
-            os: ubuntu-latest
             container: ubuntu:18.04
+            os: ubuntu-latest
             install: clang-5.0
           - toolset: clang
             compiler: clang++-6.0
@@ -144,14 +153,20 @@ jobs:
             os: ubuntu-latest
             install: clang-17
           - toolset: clang
-            cxxstd: "03,11,14,17,2a"
-            os: macos-11
+            compiler: clang++-18
+            cxxstd: "03,11,14,17,20,2b"
+            container: ubuntu:24.04
+            os: ubuntu-latest
+            install: clang-18
           - toolset: clang
             cxxstd: "03,11,14,17,20,2b"
             os: macos-12
           - toolset: clang
             cxxstd: "03,11,14,17,20,2b"
             os: macos-13
+          - toolset: clang
+            cxxstd: "03,11,14,17,20,2b"
+            os: macos-14
 
     runs-on: ${{matrix.os}}
     container: ${{matrix.container}}
@@ -161,6 +176,10 @@ jobs:
         shell: bash
 
     steps:
+      - name: Enable Node 16
+        run: |
+          echo "ACTIONS_ALLOW_USE_UNSECURE_NODE_VERSION=true" >> $GITHUB_ENV
+
       - uses: actions/checkout@v3
 
       - name: Setup container environment
@@ -194,7 +213,7 @@ jobs:
           mkdir -p libs/$LIBRARY
           cp -r $GITHUB_WORKSPACE/* libs/$LIBRARY
           git submodule update --init tools/boostdep
-          python3 tools/boostdep/depinst/depinst.py --git_args "--jobs 3" $LIBRARY
+          python3 tools/boostdep/depinst/depinst.py $LIBRARY
           ./bootstrap.sh
           ./b2 -d0 headers
 
@@ -274,9 +293,9 @@ jobs:
         include:
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
           - os: macos-12
           - os: macos-13
+          - os: macos-14
 
     runs-on: ${{matrix.os}}
 
@@ -323,9 +342,9 @@ jobs:
         include:
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
           - os: macos-12
           - os: macos-13
+          - os: macos-14
 
     runs-on: ${{matrix.os}}
 
@@ -382,9 +401,9 @@ jobs:
         include:
           - os: ubuntu-20.04
           - os: ubuntu-22.04
-          - os: macos-11
           - os: macos-12
           - os: macos-13
+          - os: macos-14
 
     runs-on: ${{matrix.os}}
 

.gitignore

@@ -0,0 +1,5 @@
+/__build__
+/toolchain.cmake
+/compile_commands.json
+/.cache
+/.vscode

build.jam

@@ -0,0 +1,22 @@
+# Copyright 2024 René Ferdinand Rivera Morell
+# Copyright 2024 Peter Dimov
+# Distributed under the Boost Software License, Version 1.0.
+# https://www.boost.org/LICENSE_1_0.txt
+
+require-b2 5.2 ;
+
+constant boost_dependencies :
+    /boost/assert//boost_assert
+    /boost/config//boost_config
+    /boost/throw_exception//boost_throw_exception
+    ;
+
+project /boost/compat ;
+
+explicit
+    [ alias boost_compat : : : : <include>include <library>$(boost_dependencies) ]
+    [ alias all : boost_compat test ]
+    ;
+
+call-if : boost-library compat
+    ;

doc/compat.adoc

@@ -17,8 +17,7 @@ https://www.boost.org/LICENSE_1_0.txt
 
 include::compat/overview.adoc[]
 include::compat/changelog.adoc[]
-include::compat/latch.adoc[]
-include::compat/shared_lock.adoc[]
+include::compat/reference.adoc[]
 include::compat/copyright.adoc[]
 
 :leveloffset: -1

doc/compat/bind_back.adoc

@@ -0,0 +1,58 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#bind_back]
+# <boost/compat/bind_back.hpp>
+:idprefix: ref_bind_back_
+
+## Description
+
+The header `<boost/compat/bind_back.hpp>` implements the {cpp}20 function
+`std::bind_back`.
+
+`bind_back` is a limited variant of `std::bind`. It only supports binding
+the last several parameters of a function object to specific argument values.
+
+## Example
+
+```
+struct X
+{
+    void f(int a, int b) const noexcept;
+};
+
+int main()
+{
+    auto fn = boost::compat::bind_back(&X::f, 1, 2);
+
+    X x;
+    fn(x); // calls x.f(1, 2)
+}
+```
+
+## Synopsis
+
+```
+namespace boost
+{
+namespace compat
+{
+
+template<class F, class... A> auto bind_back(F&& f, A&&... a);
+
+} // namespace compat
+} // namespace boost
+```
+
+## bind_back
+
+```
+template<class F, class... A> auto bind_back( F&& f, A&&... a );
+```
+
+[horizontal]
+Returns:;; A function object `fn` such that `fn(b...)` is equivalent to
+  `invoke(f, b..., a...)`.

doc/compat/bind_front.adoc

@@ -0,0 +1,58 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#bind_front]
+# <boost/compat/bind_front.hpp>
+:idprefix: ref_bind_front_
+
+## Description
+
+The header `<boost/compat/bind_front.hpp>` implements the {cpp}20 function
+`std::bind_front`.
+
+`bind_front` is a limited variant of `std::bind`. It only supports binding
+the first several parameters of a function object to specific argument values.
+
+## Example
+
+```
+struct X
+{
+    void f(int a, int b) const noexcept;
+};
+
+int main()
+{
+    X x;
+    auto fn = boost::compat::bind_front(&X::f, &x);
+
+    fn(1, 2); // calls x.f(1, 2)
+}
+```
+
+## Synopsis
+
+```
+namespace boost
+{
+namespace compat
+{
+
+template<class F, class... A> auto bind_front(F&& f, A&&... a);
+
+} // namespace compat
+} // namespace boost
+```
+
+## bind_front
+
+```
+template<class F, class... A> auto bind_front(F&& f, A&&... a);
+```
+
+[horizontal]
+Returns:;; A function object `fn` such that `fn(b...)` is equivalent to
+  `invoke(f, a..., b...)`.

doc/compat/changelog.adoc

@@ -8,6 +8,11 @@ https://www.boost.org/LICENSE_1_0.txt
 # Revision History
 :idprefix: changelog_
 
+## Changes in 1.86.0
+
+* Added `bind_front.hpp`, `bind_back.hpp`, `invoke.hpp`, `mem_fn.hpp`, `integer_sequence.hpp` and `type_traits.hpp`.
+* Added `function_ref.hpp`.
+
 ## Changes in 1.83.0
 
 * Added `latch.hpp`, an implementation of `std::latch` (contributed by Christian Mazakas.)

doc/compat/copyright.adoc

@@ -8,6 +8,6 @@ https://www.boost.org/LICENSE_1_0.txt
 # Copyright and License
 :idprefix:
 
-This documentation is copyright 2023 Peter Dimov and contributors and is
-distributed under the
+This documentation is copyright 2023, 2024 Peter Dimov and
+contributors and is distributed under the
 http://www.boost.org/LICENSE_1_0.txt[Boost Software License, Version 1.0].

doc/compat/function_ref.adoc

@@ -0,0 +1,200 @@
+////
+Copyright 2024 Christian Mazakas
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#function_ref]
+# <boost/compat/function_ref.hpp>
+:idprefix: ref_function_ref_
+
+## Description
+
+The header `<boost/compat/function_ref.hpp>` implements the {cpp}26 class
+`std::function_ref`.
+
+`function_ref` is a lightweight polymorphic function wrapper that only stores a pointer to the supplied https://en.cppreference.com/w/cpp/named_req/Callable[Callable] object and a pointer to an unspecified function, meaning it does not participate in ownership of the Callable and does not allocate. All specializations of `function_ref` satisfy https://en.cppreference.com/w/cpp/named_req/TriviallyCopyable[TriviallyCopyable].
+
+`function_ref` supports every combination of `const` and `noexcept` and is useful for writing higher-order functions as
+it can avoid a template parameter or an allocation (as `std::function` is known for).
+
+## Example
+
+```cpp
+int add(int x, int y) noexcept { return x * 10 + y; }
+
+auto add2 = [](int x, int y) { return x * 100 + y; };
+
+std::vector<boost::compat::function_ref<int(int, int)>> fns;
+fns.push_back({add});
+fns.push_back({add2});
+
+for (auto fn : fns) {
+  std::cout << fn(1, 2) << std::endl;
+}
+```
+
+## Synopsis
+
+```cpp
+namespace boost
+{
+namespace compat
+{
+
+template <class... S>
+struct function_ref;
+
+// cv is either `const` or empty
+// noex is either `true` or `false`
+template<class R, class... ArgTypes>
+class function_ref<R(ArgTypes...) cv noexcept(noex)> {
+public:
+  template<class F> function_ref(F*) noexcept;
+  template<class F> function_ref(F&&) noexcept;
+  template<auto f> function_ref(nontype_t<f>) noexcept;
+  template<auto f, class U> function_ref(nontype_t<f>, U&&) noexcept;
+  template<auto f, class T> function_ref(nontype_t<f>, cv T*) noexcept;
+
+  function_ref(const function_ref&) noexcept = default;
+  function_ref& operator=(const function_ref&) noexcept = default;
+  template<class T> function_ref& operator=(T) = delete;
+
+  R operator()(ArgTypes...) const noexcept(noex);
+};
+
+} // namespace compat
+} // namespace boost
+```
+
+## Constructors
+
+### Function Pointer Constructor
+
+```cpp
+template<class F> function_ref(F* fn) noexcept;
+```
+
+[horizontal]
+Preconditions:: `fn` != `nullptr`.
+Effects::
+Constructs a `function_ref` which uses the supplied function pointer as its Callable. +
++
+Calling the `function_ref` is expression-equivalent to `invoke_r<R>(f, call-args...)`.
+
+
+### Object Constructor
+
+```cpp
+template<class F> function_ref(F&& fn) noexcept;
+```
+
+[horizontal]
+Effects:;; Constructs a `function_ref` that stores the address of the supplied Callable object `fn`. This overload only
+participates in resolution when `fn` is not a pointer-to-member or pointer-to-member-function. +
++
+Calling the `function_ref` is expression-equivalent to: + `invoke_r<R>(static_cast<cv T&>(f), call-args...)`.
+
+### Pointer to Member Function Constructor
+
+```cpp
+template<auto f> function_ref(nontype_t<f>) noexcept;
+```
+
+[horizontal]
+Effects:;; Constructs a `function_ref` using the supplied pointer to member function. This overload only participates
+in resolution when `f` is a pointer to member or pointer to member function. +
++
+Calling the `function_ref` is express-equivalent to: `invoke_r<R>(f, class-args)`.
+Example:;;
++
+--
+```cpp
+struct point { int x = 1, y = 2; };
+
+point p;
+compat::function_ref<int(point const&)> f(compat::nontype_t<&point::x>{});
+
+BOOST_TEST_EQ(f(p), 1);
+```
+--
+
+### Bound Object Constructor
+
+```cpp
+template<auto f, class U> function_ref(nontype_t<f>, U&&) noexcept;
+```
+
+[horizontal]
+Effects:;; Constructs a `function_ref` using the supplied pointer to member or pointer to member function and a reference
+to an object to bind it to. +
++
+This overload only participates in resolution if `is_rvalue_reference_v<U&&>` is false.
+Example:;;
++
+--
+```cpp
+struct point { int x = 1, y = 2; };
+
+point p;
+compat::function_ref<int()> f(compat::nontype_t<&point::x>{}, p);
+
+BOOST_TEST_EQ(f(), 1);
+```
+--
+
+### Bound Pointer Constructor
+
+```cpp
+template<auto f, class T> function_ref(nontype_t<f>, cv T*) noexcept;
+```
+
+[horizontal]
+Effects:;; Constructs a `function_ref` using the supplied pointer to member or pointer to member function and a pointer
+to an object.
+Example:;;
++
+--
+```cpp
+struct point { int x = 1, y = 2; };
+
+point p;
+compat::function_ref<int()> f(compat::nontype_t<&point::x>{}, &p);
+
+BOOST_TEST_EQ(f(), 1);
+```
+--
+
+### Copy Constructor
+
+```cpp
+function_ref(const function_ref&) noexcept = default;
+```
+
+[horizontal]
+Effects:;; `function_ref` is a TriviallyCopyable type.
+
+## Member Functions
+
+### call operator
+
+```cpp
+R operator()(ArgTypes...) const noexcept(noex);
+```
+
+[horizontal]
+Effects:;; Invokes the underlying Callable object by forwarding the supplied arguments.
+
+## Assignment
+
+### Copy Assignment
+
+```cpp
+function_ref& operator=(const function_ref&) noexcept = default;
+template<class T> function_ref& operator=(T) = delete;
+```
+
+[horizontal]
+Effects:;; `operator=(T)` participates in overload resolution if:
+* `T` is not the same as `function_ref`
+* `is_pointer_v<T>` is `false`.

doc/compat/integer_sequence.adoc

@@ -0,0 +1,69 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#integer_sequence]
+# <boost/compat/integer_sequence.hpp>
+:idprefix: ref_integer_sequence_
+
+## Description
+
+The header `<boost/compat/integer_sequence.hpp>` implements the {cpp}14 utilities
+`std::integer_sequence`, `std::index_sequence`, `std::make_integer_sequence`,
+`std::make_index_sequence`, and `std::index_sequence_for`.
+
+## Synopsis
+
+```
+namespace boost
+{
+namespace compat
+{
+
+template<class T, T... I> struct integer_sequence;
+
+template<class T, T N> using make_integer_sequence = /*...*/;
+
+template<std::size_t... I> using index_sequence = /*...*/;
+
+template<std::size_t N> using make_index_sequence = /*...*/;
+
+template<class... T> using index_sequence_for = /*...*/;
+
+} // namespace compat
+} // namespace boost
+```
+
+## integer_sequence
+
+```
+template<class T, T... I> struct integer_sequence {};
+```
+
+## make_integer_sequence
+
+```
+template<class T, T N> using make_integer_sequence = /*...*/;
+```
+
+`make_integer_sequence<T, N>` is an alias for `integer_sequence<T, 0, 1, 2, ..., N-1>`.
+
+## index_sequence
+
+```
+template<std::size_t... I> using index_sequence = integer_sequence<std::size_t, I...>;
+```
+
+## make_index_sequence
+
+```
+template<std::size_t N> using make_index_sequence = make_integer_sequence<std::size_t, N>;
+```
+
+## index_sequence_for
+
+```
+template<class... T> using index_sequence_for = make_integer_sequence<std::size_t, sizeof...(T)>;
+```

doc/compat/invoke.adoc

@@ -0,0 +1,130 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#invoke]
+# <boost/compat/invoke.hpp>
+:idprefix: ref_invoke_
+
+## Description
+
+The header `<boost/compat/invoke.hpp>` implements the {cpp}17 function
+`std::invoke`, the {cpp}23 function `std::invoke_r`, and the associated
+utilities `invoke_result_t`, `is_invocable`, `is_invocable_r`,
+`is_nothrow_invocable`, and `is_nothrow_invocable_r`.
+
+`invoke(f, a...)` generally returns `f(a...)`, but when `f` is a pointer to
+member, it invokes it as if by returning `mem_fn(f)(a...)`. This allows
+functions, function objects, and pointers to members to be treated uniformly
+by components such as `bind_front`.
+
+`invoke_r<R>(f, a...)` returns `invoke(f, a...)`, converted to `R`.
+
+## Example
+
+```
+struct X
+{
+    void f(int a, int b) const noexcept;
+};
+
+int main()
+{
+    X x;
+    boost::compat::invoke(&X::f, x, 1, 2); // calls x.f(1, 2)
+}
+```
+
+## Synopsis
+
+```
+namespace boost
+{
+namespace compat
+{
+
+template<class F, class... A> auto invoke(F&& f, A&&... a);
+
+template<class F, class... A> using invoke_result_t = /*...*/;
+
+template<class F, class... A> struct is_invocable;
+
+template<class F, class... A> struct is_nothrow_invocable;
+
+template<class R, class F, class... A> R invoke_r(F&& f, A&&... a);
+
+template<class R, class F, class... A> struct is_invocable_r;
+
+template<class R, class F, class... A> struct is_nothrow_invocable_r;
+
+} // namespace compat
+} // namespace boost
+```
+
+## invoke
+
+```
+template<class F, class... A> auto invoke(F&& f, A&&... a) noexcept(/*...*/) -> /*...*/;
+```
+
+[horizontal]
+Returns:;;
+  * `std::forward<F>(f)(std::forward<A>(a)...)`, when `f` is not a pointer to member;
+  * `mem_fn(f)(std::forward<A>(a)...)`, otherwise.
+Constraints:;; the return expression must be valid.
+Remarks:;; The return type is `decltype(r)`, and the `noexcept` clause is `noexcept(noexcept(r))`, where `r` is the return expression.
+
+## invoke_result_t
+
+```
+template<class F, class... A> using invoke_result_t =
+  decltype( invoke(std::declval<F>(), std::declval<A>()...) );
+```
+
+## is_invocable
+
+```
+template<class F, class... A> struct is_invocable: public /*...*/;
+```
+
+The base class of `is_invocable<F, A...>` is `std::true_type` when `invoke(std::declval<F>(), std::declval<A>()...)` is a valid expression, `std::false_type` otherwise.
+
+## is_nothrow_invocable
+
+```
+template<class F, class... A> struct is_nothrow_invocable: public /*...*/;
+```
+
+The base class of `is_nothrow_invocable<F, A...>` is `std::false_type` when `is_invocable<F, A...>::value` is `false`, `std::integral_constant<bool, noexcept(invoke(std::declval<F>(), std::declval<A>()...))>` otherwise.
+
+## invoke_r
+
+```
+template<class R, class F, class... A> R invoke_r(F&& f, A&&... a) noexcept(/*...*/);
+```
+
+[horizontal]
+Returns:;;
+  * `static_cast<R>(invoke(std::forward<F>(f), std::forward<A>(a)...))`, when `R` is (possibly cv-qualified) `void`;
+  * `invoke(std::forward<F>(f), std::forward<A>(a)...)`, implicitly converted to `R`, otherwise.
+Constraints:;; `is_invocable<F, A...>::value` must be `true` and, if `R` is not cv `void`, `std::is_convertible<invoke_result_t<F, A...>, R>::value` must be `true`.
+Remarks:;; The `noexcept` clause is `noexcept(noexcept(static_cast<R>(invoke(std::forward<F>(f), std::forward<A>(a)...))))`.
+
+## is_invocable_r
+
+```
+template<class R, class F, class... A> struct is_invocable: public /*...*/;
+```
+
+The base class of `is_invocable_r<R, F, A...>` is `std::true_type` when `invoke_r<R>(std::declval<F>(), std::declval<A>()...)` is a valid expression, `std::false_type` otherwise.
+
+## is_nothrow_invocable_r
+
+```
+template<class R, class F, class... A> struct is_nothrow_invocable: public /*...*/;
+```
+
+The base class of `is_nothrow_invocable<R, F, A...>` is `std::false_type` when `is_invocable_r<R, F, A...>::value` is `false`, `std::integral_constant<bool, noexcept(invoke_r<R>(std::declval<F>(), std::declval<A>()...))>` otherwise.
+

doc/compat/latch.adoc

@@ -6,7 +6,7 @@ https://www.boost.org/LICENSE_1_0.txt
 
 [#latch]
 # <boost/compat/latch.hpp>
-:idprefix: latch_
+:idprefix: ref_latch_
 
 ## Description
 

doc/compat/mem_fn.adoc

@@ -0,0 +1,67 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#mem_fn]
+# <boost/compat/mem_fn.hpp>
+:idprefix: ref_mem_fn_
+
+## Description
+
+The header `<boost/compat/mem_fn.hpp>` implements the {cpp}11 function
+`std::mem_fn`.
+
+`mem_fn(pm)`, where `pm` is a pointer to member, returns a function object
+that can be used to invoke the member function, or obtain a reference to the
+data member, using a function call syntax.
+
+Even though `std::mem_fn` is {cpp}11, later standards place stricter
+requirements on the returned function object (it needs to be SFINAE friendly
+and propagate `noexcept` correctly.) `boost::compat::mem_fn` implements
+these stricter requirements.
+
+## Example
+
+```
+struct X
+{
+    void f(int a, int b) const noexcept;
+};
+
+int main()
+{
+    auto fn = boost::compat::mem_fn(&X::f);
+
+    X x;
+    fn(x, 1, 2); // calls x.f(1, 2)
+}
+```
+
+## Synopsis
+
+```
+namespace boost
+{
+namespace compat
+{
+
+template<class M, class T> auto mem_fn(M T::* pm) noexcept;
+
+} // namespace compat
+} // namespace boost
+```
+
+## mem_fn
+
+```
+template<class M, class T> auto mem_fn(M T::* pm) noexcept;
+```
+
+[horizontal]
+Returns:;; A function object `fn` such that:
+  * `fn(x, a...)` is equivalent to `(x.*pm)(a...)`, when `M` is a function type and the type of `X` is `T` or derived from `T`;
+  * `fn(x, a...)` is equivalent to `((*x).*pm)(a...)`, when `M` is a function type and the type of `X` is not `T` or derived from `T`;
+  * `fn(x)` is equivalent to `x.*pm`, when `M` is an object type and the type of `X` is `T` or derived from `T`;
+  * `fn(x)` is equivalent to `(*x).*pm`, when `M` is an object type and the type of `X` is not `T` or derived from `T`.

doc/compat/reference.adoc

@@ -0,0 +1,15 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+include::bind_back.adoc[]
+include::bind_front.adoc[]
+include::function_ref.adoc[]
+include::integer_sequence.adoc[]
+include::invoke.adoc[]
+include::latch.adoc[]
+include::mem_fn.adoc[]
+include::shared_lock.adoc[]
+include::type_traits.adoc[]

doc/compat/shared_lock.adoc

@@ -6,7 +6,7 @@ https://www.boost.org/LICENSE_1_0.txt
 
 [#shared_lock]
 # <boost/compat/shared_lock.hpp>
-:idprefix: shared_lock_
+:idprefix: ref_shared_lock_
 
 ## Description
 
@@ -129,7 +129,7 @@ shared_lock( mutex_type& m, std::adopt_lock_t );
 [horizontal]
 Preconditions:;; `m` must be held by a previous call to `m.lock_shared()` or a
 successful call to `m.try_lock_shared()`.
-PostConditions:;; `mutex() == std::addressof(m)` and `owns_lock() == true`.
+Postconditions:;; `mutex() == std::addressof(m)` and `owns_lock() == true`.
 
 ### Copy Constructor
 

doc/compat/type_traits.adoc

@@ -0,0 +1,45 @@
+////
+Copyright 2024 Peter Dimov
+Distributed under the Boost Software License, Version 1.0.
+https://www.boost.org/LICENSE_1_0.txt
+////
+
+[#type_traits]
+# <boost/compat/type_traits.hpp>
+:idprefix: ref_type_traits_
+
+## Description
+
+The header `<boost/compat/type_traits.hpp>` implements some of the
+post-{cpp}11 additions to the standard header `<type_traits>`.
+
+## Synopsis
+
+```
+#include <type_traits>
+
+namespace boost
+{
+namespace compat
+{
+
+template<class T> using remove_const_t = typename std::remove_const<T>::type;
+
+template<class T> using remove_cv_t = typename std::remove_cv<T>::type;
+
+template<class T> using remove_reference_t = typename std::remove_reference<T>::type;
+
+template<class T> using remove_cvref_t = remove_cv_t<remove_reference_t<T>>;
+
+template<class T> using decay_t = typename std::decay<T>::type;
+
+template<bool B, class T = void> using enable_if_t = typename std::enable_if<B, T>::type;
+
+template<bool B, class T, class F> using conditional_t = typename std::conditional<B, T, F>::type;
+
+template<class... T> using void_t = void;
+
+
+} // namespace compat
+} // namespace boost
+```

include/boost/compat/bind_back.hpp

@@ -0,0 +1,72 @@
+#ifndef BOOST_COMPAT_BIND_BACK_HPP_INCLUDED
+#define BOOST_COMPAT_BIND_BACK_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/compat/type_traits.hpp>
+#include <boost/compat/integer_sequence.hpp>
+#include <boost/compat/detail/returns.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <tuple>
+#include <utility>
+
+namespace boost {
+namespace compat {
+
+namespace detail {
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+# pragma warning(push)
+# pragma warning(disable: 4100) // 'a': unreferenced formal parameter
+#endif
+
+template<class F, class A, class... B, std::size_t... I>
+static constexpr auto invoke_bind_back_( F&& f, A&& a, index_sequence<I...>, B&&... b )
+    BOOST_COMPAT_RETURNS( compat::invoke( std::forward<F>(f), std::forward<B>(b)..., std::get<I>( std::forward<A>(a) )... ) )
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+# pragma warning(pop)
+#endif
+
+template<class F, class... A> class bind_back_
+{
+private:
+
+    F f_;
+    std::tuple<A...> a_;
+
+public:
+
+    template<class F2, class... A2>
+    constexpr bind_back_( F2&& f2, A2&&... a2 ): f_( std::forward<F2>(f2) ), a_( std::forward<A2>(a2)... ) {}
+
+public:
+
+    template<class... B> BOOST_CXX14_CONSTEXPR auto operator()( B&&... b ) &
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_back_( f_, a_, make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> constexpr auto operator()( B&&... b ) const &
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_back_( f_, a_, make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> BOOST_CXX14_CONSTEXPR auto operator()( B&&... b ) &&
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_back_( std::move(f_), std::move(a_), make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> constexpr auto operator()( B&&... b ) const &&
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_back_( std::move(f_), std::move(a_), make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+};
+
+} // namespace detail
+
+template<class F, class... A> constexpr auto bind_back( F&& f, A&&... a ) -> detail::bind_back_< decay_t<F>, decay_t<A>... >
+{
+    return { std::forward<F>(f), std::forward<A>(a)... };
+}
+
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_BIND_BACK_HPP_INCLUDED

include/boost/compat/bind_front.hpp

@@ -0,0 +1,72 @@
+#ifndef BOOST_COMPAT_BIND_FRONT_HPP_INCLUDED
+#define BOOST_COMPAT_BIND_FRONT_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/compat/type_traits.hpp>
+#include <boost/compat/integer_sequence.hpp>
+#include <boost/compat/detail/returns.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <tuple>
+#include <utility>
+
+namespace boost {
+namespace compat {
+
+namespace detail {
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+# pragma warning(push)
+# pragma warning(disable: 4100) // 'a': unreferenced formal parameter
+#endif
+
+template<class F, class A, class... B, std::size_t... I>
+static constexpr auto invoke_bind_front_( F&& f, A&& a, index_sequence<I...>, B&&... b )
+    BOOST_COMPAT_RETURNS( compat::invoke( std::forward<F>(f), std::get<I>( std::forward<A>(a) )..., std::forward<B>(b)... ) )
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+# pragma warning(pop)
+#endif
+
+template<class F, class... A> class bind_front_
+{
+private:
+
+    F f_;
+    std::tuple<A...> a_;
+
+public:
+
+    template<class F2, class... A2>
+    constexpr bind_front_( F2&& f2, A2&&... a2 ): f_( std::forward<F2>(f2) ), a_( std::forward<A2>(a2)... ) {}
+
+public:
+
+    template<class... B> BOOST_CXX14_CONSTEXPR auto operator()( B&&... b ) &
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_front_( f_, a_, make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> constexpr auto operator()( B&&... b ) const &
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_front_( f_, a_, make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> BOOST_CXX14_CONSTEXPR auto operator()( B&&... b ) &&
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_front_( std::move(f_), std::move(a_), make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+
+    template<class... B> constexpr auto operator()( B&&... b ) const &&
+        BOOST_COMPAT_RETURNS( detail::invoke_bind_front_( std::move(f_), std::move(a_), make_index_sequence<sizeof...(A)>(), std::forward<B>(b)... ) )
+};
+
+} // namespace detail
+
+template<class F, class... A> constexpr auto bind_front( F&& f, A&&... a ) -> detail::bind_front_< decay_t<F>, decay_t<A>... >
+{
+    return { std::forward<F>(f), std::forward<A>(a)... };
+}
+
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_BIND_FRONT_HPP_INCLUDED

include/boost/compat/detail/returns.hpp

@@ -0,0 +1,10 @@
+#ifndef BOOST_COMPAT_DETAIL_RETURNS_HPP_INCLUDED
+#define BOOST_COMPAT_DETAIL_RETURNS_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#define BOOST_COMPAT_RETURNS(...) noexcept(noexcept(__VA_ARGS__)) -> decltype(__VA_ARGS__) { return __VA_ARGS__; }
+
+#endif // BOOST_COMPAT_DETAIL_RETURNS_HPP_INCLUDED

include/boost/compat/function_ref.hpp

@@ -0,0 +1,314 @@
+#ifndef BOOST_COMPAT_FUNCTION_REF_HPP_INCLUDED
+#define BOOST_COMPAT_FUNCTION_REF_HPP_INCLUDED
+
+// Copyright 2024 Christian Mazakas.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/compat/type_traits.hpp>
+
+#include <type_traits>
+#include <utility>
+
+#if defined(__cpp_nontype_template_parameter_auto) && __cpp_nontype_template_parameter_auto >= 201606L
+#define BOOST_COMPAT_HAS_AUTO_NTTP
+#endif
+
+namespace boost {
+namespace compat {
+
+template <class... S>
+struct function_ref;
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+template <auto V>
+struct nontype_t {
+  explicit nontype_t() = default;
+};
+
+#endif
+
+namespace detail {
+
+template <bool NoEx>
+union thunk_storage {
+  void* pobj_;
+  void (*pfn_)() noexcept(NoEx);
+};
+
+template <bool NoEx, class Fp, class R, class... Args>
+struct invoke_function_holder {
+  static R invoke_function(thunk_storage<NoEx> s, Args&&... args) noexcept(NoEx) {
+    auto f = reinterpret_cast<Fp>(s.pfn_);
+    return compat::invoke_r<R>(f, std::forward<Args>(args)...);
+  }
+};
+
+template <bool Const, bool NoEx, class F, class R, class... Args>
+struct invoke_object_holder {
+  static R invoke_object(thunk_storage<NoEx> s, Args&&... args) noexcept(NoEx) {
+    using T = remove_reference_t<F>;
+    using cv_T = conditional_t<Const, add_const_t<T>, T>;
+    return compat::invoke_r<R>(*static_cast<cv_T*>(s.pobj_), std::forward<Args>(args)...);
+  }
+};
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+template <auto f, bool Const, bool NoEx, class R, class... Args>
+struct invoke_mem_fn_holder {
+  static R invoke_mem_fn(thunk_storage<NoEx> /* s */, Args&&... args) noexcept(NoEx) {
+    return compat::invoke_r<R>(f, std::forward<Args>(args)...);
+  }
+};
+
+template <auto f, class U, bool Const, bool NoEx, class R, class... Args>
+struct invoke_target_mem_fn_holder {
+  static R invoke_mem_fn(thunk_storage<NoEx> s, Args&&... args) noexcept(NoEx) {
+    using T = remove_reference_t<U>;
+    using cv_T = conditional_t<Const, add_const_t<T>, T>;
+    return compat::invoke_r<R>(f, *static_cast<cv_T*>(s.pobj_), std::forward<Args>(args)...);
+  }
+};
+
+template <auto f, class T, bool Const, bool NoEx, class R, class... Args>
+struct invoke_ptr_mem_fn_holder {
+  static R invoke_mem_fn(thunk_storage<NoEx> s, Args&&... args) noexcept(NoEx) {
+    using cv_T = conditional_t<Const, add_const_t<T>, T>;
+    return compat::invoke_r<R>(f, static_cast<cv_T*>(s.pobj_), std::forward<Args>(args)...);
+  }
+};
+
+#endif
+
+template <bool Const, bool NoEx, class R, class... Args>
+struct function_ref_base {
+private:
+  thunk_storage<NoEx> thunk_ = nullptr;
+  R (*invoke_)(thunk_storage<NoEx>, Args&&...) noexcept(NoEx) = nullptr;
+
+public:
+  struct fp_tag {};
+  struct obj_tag {};
+  struct mem_fn_tag {};
+
+  template <class F>
+  function_ref_base(fp_tag, F* fn) noexcept
+      : thunk_{}, invoke_(&invoke_function_holder<NoEx, F*, R, Args...>::invoke_function) {
+    thunk_.pfn_ = reinterpret_cast<decltype(thunk_.pfn_)>(fn);
+  }
+
+  template <class F>
+  function_ref_base(obj_tag, F&& fn) noexcept
+      : thunk_{}, invoke_(&invoke_object_holder<Const, NoEx, F, R, Args...>::invoke_object) {
+    thunk_.pobj_ = const_cast<void*>(static_cast<void const*>(std::addressof(fn)));
+  }
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+  template <auto f, class F = decltype(f)>
+  function_ref_base(mem_fn_tag, nontype_t<f>)
+      : thunk_{}, invoke_(&invoke_mem_fn_holder<F{f}, Const, NoEx, R, Args...>::invoke_mem_fn) {
+    thunk_.pobj_ = nullptr;
+  }
+
+  template <auto f, class U, class F = decltype(f)>
+  function_ref_base(mem_fn_tag, nontype_t<f>, U&& obj)
+      : thunk_{}, invoke_(&invoke_target_mem_fn_holder<F{f}, U, Const, NoEx, R, Args...>::invoke_mem_fn) {
+    thunk_.pobj_ = const_cast<void*>(static_cast<void const*>(std::addressof(obj)));
+  }
+
+  template <auto f, class T, class F = decltype(f)>
+  function_ref_base(mem_fn_tag, nontype_t<f>, T* obj)
+      : thunk_{}, invoke_(&invoke_ptr_mem_fn_holder<F{f}, T, Const, NoEx, R, Args...>::invoke_mem_fn) {
+    thunk_.pobj_ = const_cast<void*>(static_cast<void const*>(obj));
+  }
+
+#endif
+
+  function_ref_base(const function_ref_base&) noexcept = default;
+  function_ref_base& operator=(const function_ref_base&) noexcept = default;
+
+  R operator()(Args&&... args) const noexcept(NoEx) { return this->invoke_(thunk_, std::forward<Args>(args)...); }
+};
+
+} // namespace detail
+
+template <class R, class... Args>
+struct function_ref<R(Args...)> : public detail::function_ref_base<false, false, R, Args...> {
+private:
+  using base_type = detail::function_ref_base<false, false, R, Args...>;
+  using typename base_type::fp_tag;
+  using typename base_type::mem_fn_tag;
+  using typename base_type::obj_tag;
+
+  template <class... T>
+  using is_invocable_using = boost::compat::is_invocable_r<R, T..., Args...>;
+
+public:
+  template <class F, enable_if_t<std::is_function<F>::value && is_invocable_using<F>::value, int> = 0>
+  function_ref(F* fn) noexcept : base_type(fp_tag{}, fn) {}
+
+  template <class F, class T = remove_reference_t<F>,
+            enable_if_t<!std::is_same<remove_cvref_t<F>, function_ref>::value && !std::is_member_pointer<T>::value &&
+                            is_invocable_using<T&>::value,
+                        int> = 0>
+  function_ref(F&& fn) noexcept : base_type(obj_tag{}, fn) {}
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+  template <auto f, class F = decltype(f), enable_if_t<is_invocable_using<F>::value, int> = 0>
+  function_ref(nontype_t<f> x) noexcept : base_type(mem_fn_tag{}, x) {}
+
+  template <auto f, class U, class T = remove_reference_t<U>, class F = decltype(f),
+            enable_if_t<!std::is_rvalue_reference_v<U&&> && is_invocable_using<F, T&>::value, int> = 0>
+  function_ref(nontype_t<f> x, U&& obj) noexcept : base_type(mem_fn_tag{}, x, std::forward<U>(obj)) {}
+
+  template <auto f, class T, class F = decltype(f), enable_if_t<is_invocable_using<F, T*>::value, int> = 0>
+  function_ref(nontype_t<f> x, T* obj) noexcept : base_type(mem_fn_tag{}, x, obj) {}
+
+#endif
+
+  function_ref(const function_ref&) noexcept = default;
+  function_ref& operator=(const function_ref&) noexcept = default;
+
+  template <class T, enable_if_t<!std::is_same<T, function_ref>::value && !std::is_pointer<T>::value, int> = 0>
+  function_ref& operator=(T) = delete;
+};
+
+template <class R, class... Args>
+struct function_ref<R(Args...) const> : public detail::function_ref_base<true, false, R, Args...> {
+private:
+  using base_type = detail::function_ref_base<true, false, R, Args...>;
+  using typename base_type::fp_tag;
+  using typename base_type::mem_fn_tag;
+  using typename base_type::obj_tag;
+
+  template <class... T>
+  using is_invocable_using = boost::compat::is_invocable_r<R, T..., Args...>;
+
+public:
+  template <class F, enable_if_t<std::is_function<F>::value && is_invocable_using<F>::value, int> = 0>
+  function_ref(F* fn) noexcept : base_type(fp_tag{}, fn) {}
+
+  template <class F, class T = remove_reference_t<F>,
+            enable_if_t<!std::is_same<remove_cvref_t<F>, function_ref>::value && !std::is_member_pointer<T>::value &&
+                            is_invocable_using<T const&>::value,
+                        int> = 0>
+  function_ref(F&& fn) noexcept : base_type(obj_tag{}, fn) {}
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+  template <auto f, class F = decltype(f), enable_if_t<is_invocable_using<F>::value, int> = 0>
+  function_ref(nontype_t<f> x) noexcept : base_type(mem_fn_tag{}, x) {}
+
+  template <auto f, class U, class T = remove_reference_t<U>, class F = decltype(f),
+            enable_if_t<!std::is_rvalue_reference_v<U&&> && is_invocable_using<F, T const&>::value, int> = 0>
+  function_ref(nontype_t<f> x, U&& obj) noexcept : base_type(mem_fn_tag{}, x, std::forward<U>(obj)) {}
+
+  template <auto f, class T, class F = decltype(f), enable_if_t<is_invocable_using<F, T const*>::value, int> = 0>
+  function_ref(nontype_t<f> x, T const* obj) noexcept : base_type(mem_fn_tag{}, x, obj) {}
+
+#endif
+
+  function_ref(const function_ref&) noexcept = default;
+  function_ref& operator=(const function_ref&) noexcept = default;
+
+  template <class T, enable_if_t<!std::is_same<T, function_ref>::value && !std::is_pointer<T>::value, int> = 0>
+  function_ref& operator=(T) = delete;
+};
+
+#if defined(__cpp_noexcept_function_type)
+
+template <class R, class... Args>
+struct function_ref<R(Args...) noexcept> : public detail::function_ref_base<false, true, R, Args...> {
+private:
+  using base_type = detail::function_ref_base<false, true, R, Args...>;
+  using typename base_type::fp_tag;
+  using typename base_type::mem_fn_tag;
+  using typename base_type::obj_tag;
+
+  template <class... T>
+  using is_invocable_using = boost::compat::is_nothrow_invocable_r<R, T..., Args...>;
+
+public:
+  template <class F, enable_if_t<std::is_function<F>::value && is_invocable_using<F>::value, int> = 0>
+  function_ref(F* fn) noexcept : base_type(fp_tag{}, fn) {}
+
+  template <class F, class T = remove_reference_t<F>,
+            enable_if_t<!std::is_same<remove_cvref_t<F>, function_ref>::value && !std::is_member_pointer<T>::value &&
+                            is_invocable_using<T&>::value,
+                        int> = 0>
+  function_ref(F&& fn) noexcept : base_type(obj_tag{}, fn) {}
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+  template <auto f, class F = decltype(f), enable_if_t<is_invocable_using<F>::value, int> = 0>
+  function_ref(nontype_t<f> x) noexcept : base_type(mem_fn_tag{}, x) {}
+
+  template <auto f, class U, class T = remove_reference_t<U>, class F = decltype(f),
+            enable_if_t<!std::is_rvalue_reference_v<U&&> && is_invocable_using<F, T&>::value, int> = 0>
+  function_ref(nontype_t<f> x, U&& obj) noexcept : base_type(mem_fn_tag{}, x, std::forward<U>(obj)) {}
+
+  template <auto f, class T, class F = decltype(f), enable_if_t<is_invocable_using<F, T*>::value, int> = 0>
+  function_ref(nontype_t<f> x, T* obj) noexcept : base_type(mem_fn_tag{}, x, obj) {}
+
+#endif
+
+  function_ref(const function_ref&) noexcept = default;
+  function_ref& operator=(const function_ref&) noexcept = default;
+
+  template <class T, enable_if_t<!std::is_same<T, function_ref>::value && !std::is_pointer<T>::value, int> = 0>
+  function_ref& operator=(T) = delete;
+};
+
+template <class R, class... Args>
+struct function_ref<R(Args...) const noexcept> : public detail::function_ref_base<true, true, R, Args...> {
+private:
+  using base_type = detail::function_ref_base<true, true, R, Args...>;
+  using typename base_type::fp_tag;
+  using typename base_type::mem_fn_tag;
+  using typename base_type::obj_tag;
+
+  template <class... T>
+  using is_invocable_using = boost::compat::is_nothrow_invocable_r<R, T..., Args...>;
+
+public:
+  template <class F, enable_if_t<std::is_function<F>::value && is_invocable_using<F>::value, int> = 0>
+  function_ref(F* fn) noexcept : base_type(fp_tag{}, fn) {}
+
+  template <class F, class T = remove_reference_t<F>,
+            enable_if_t<!std::is_same<remove_cvref_t<F>, function_ref>::value && !std::is_member_pointer<T>::value &&
+                            is_invocable_using<T const&>::value,
+                        int> = 0>
+  function_ref(F&& fn) noexcept : base_type(obj_tag{}, fn) {}
+
+#if defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+
+  template <auto f, class F = decltype(f), enable_if_t<is_invocable_using<F>::value, int> = 0>
+  function_ref(nontype_t<f> x) noexcept : base_type(mem_fn_tag{}, x) {}
+
+  template <auto f, class U, class T = remove_reference_t<U>, class F = decltype(f),
+            enable_if_t<!std::is_rvalue_reference_v<U&&> && is_invocable_using<F, T const&>::value, int> = 0>
+  function_ref(nontype_t<f> x, U&& obj) noexcept : base_type(mem_fn_tag{}, x, std::forward<U>(obj)) {}
+
+  template <auto f, class T, class F = decltype(f), enable_if_t<is_invocable_using<F, T const*>::value, int> = 0>
+  function_ref(nontype_t<f> x, T const* obj) noexcept : base_type(mem_fn_tag{}, x, obj) {}
+
+#endif
+
+  function_ref(const function_ref&) noexcept = default;
+  function_ref& operator=(const function_ref&) noexcept = default;
+
+  template <class T, enable_if_t<!std::is_same<T, function_ref>::value && !std::is_pointer<T>::value, int> = 0>
+  function_ref& operator=(T) = delete;
+};
+
+#endif
+
+} // namespace compat
+} // namespace boost
+
+#endif // #ifndef BOOST_COMPAT_FUNCTION_REF_HPP_INCLUDED

include/boost/compat/integer_sequence.hpp

@@ -0,0 +1,120 @@
+#ifndef BOOST_COMPAT_INTEGER_SEQUENCE_HPP_INCLUDED
+#define BOOST_COMPAT_INTEGER_SEQUENCE_HPP_INCLUDED
+
+// Copyright 2015, 2017, 2019 Peter Dimov.
+//
+// Distributed under the Boost Software License, Version 1.0.
+//
+// See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt
+
+#include <cstddef>
+
+#if defined(_MSC_VER) || defined(__GNUC__)
+# pragma push_macro( "I" )
+# undef I
+#endif
+
+#if defined(__has_builtin)
+# if __has_builtin(__make_integer_seq)
+#  define BOOST_COMPAT_HAS_MAKE_INTEGER_SEQ
+# endif
+#endif
+
+namespace boost
+{
+namespace compat
+{
+
+// integer_sequence
+template<class T, T... I> struct integer_sequence
+{
+};
+
+#if defined(BOOST_COMPAT_HAS_MAKE_INTEGER_SEQ)
+
+template<class T, T N> using make_integer_sequence = __make_integer_seq<integer_sequence, T, N>;
+
+#else
+
+// detail::make_integer_sequence_impl
+namespace detail
+{
+
+// iseq_if_c
+template<bool C, class T, class E> struct iseq_if_c_impl;
+
+template<class T, class E> struct iseq_if_c_impl<true, T, E>
+{
+    using type = T;
+};
+
+template<class T, class E> struct iseq_if_c_impl<false, T, E>
+{
+    using type = E;
+};
+
+template<bool C, class T, class E> using iseq_if_c = typename iseq_if_c_impl<C, T, E>::type;
+
+// iseq_identity
+template<class T> struct iseq_identity
+{
+    using type = T;
+};
+
+template<class S1, class S2> struct append_integer_sequence;
+
+template<class T, T... I, T... J> struct append_integer_sequence<integer_sequence<T, I...>, integer_sequence<T, J...>>
+{
+    using type = integer_sequence< T, I..., ( J + sizeof...(I) )... >;
+};
+
+template<class T, T N> struct make_integer_sequence_impl;
+
+template<class T, T N> struct make_integer_sequence_impl_
+{
+private:
+
+    static_assert( N >= 0, "make_integer_sequence<T, N>: N must not be negative" );
+
+    static T const M = N / 2;
+    static T const R = N % 2;
+
+    using S1 = typename make_integer_sequence_impl<T, M>::type;
+    using S2 = typename append_integer_sequence<S1, S1>::type;
+    using S3 = typename make_integer_sequence_impl<T, R>::type;
+    using S4 = typename append_integer_sequence<S2, S3>::type;
+
+public:
+
+    using type = S4;
+};
+
+template<class T, T N> struct make_integer_sequence_impl: iseq_if_c<N == 0, iseq_identity<integer_sequence<T>>, iseq_if_c<N == 1, iseq_identity<integer_sequence<T, 0>>, make_integer_sequence_impl_<T, N> > >
+{
+};
+
+} // namespace detail
+
+// make_integer_sequence
+template<class T, T N> using make_integer_sequence = typename detail::make_integer_sequence_impl<T, N>::type;
+
+#endif // defined(BOOST_COMPAT_HAS_MAKE_INTEGER_SEQ)
+
+// index_sequence
+template<std::size_t... I> using index_sequence = integer_sequence<std::size_t, I...>;
+
+// make_index_sequence
+template<std::size_t N> using make_index_sequence = make_integer_sequence<std::size_t, N>;
+
+// index_sequence_for
+template<class... T> using index_sequence_for = make_integer_sequence<std::size_t, sizeof...(T)>;
+
+} // namespace compat
+} // namespace boost
+
+#if defined(_MSC_VER) || defined(__GNUC__)
+# pragma pop_macro( "I" )
+#endif
+
+#endif // #ifndef BOOST_COMPAT_INTEGER_SEQUENCE_HPP_INCLUDED

include/boost/compat/invoke.hpp

@@ -0,0 +1,119 @@
+#ifndef BOOST_COMPAT_INVOKE_HPP_INCLUDED
+#define BOOST_COMPAT_INVOKE_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/mem_fn.hpp>
+#include <boost/compat/type_traits.hpp>
+#include <boost/compat/detail/returns.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <utility>
+
+namespace boost {
+namespace compat {
+
+// invoke
+
+template<class F, class... A>
+constexpr auto invoke( F&& f, A&&... a )
+BOOST_COMPAT_RETURNS( std::forward<F>(f)(std::forward<A>(a)...) )
+
+template<class M, class T, class... A>
+constexpr auto invoke( M T::* pm, A&&... a )
+BOOST_COMPAT_RETURNS( compat::mem_fn(pm)(std::forward<A>(a)...) )
+
+// invoke_result_t
+
+template<class F, class... A> using invoke_result_t = decltype( compat::invoke( std::declval<F>(), std::declval<A>()... ) );
+
+// is_invocable
+
+namespace detail {
+
+template<class, class F, class... A> struct is_invocable_: std::false_type {};
+template<class F, class... A> struct is_invocable_< void_t<invoke_result_t<F, A...>>, F, A... >: std::true_type {};
+
+} // namespace detail
+
+template<class F, class... A> struct is_invocable: detail::is_invocable_<void, F, A...> {};
+
+// is_nothrow_invocable
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+template<class F, class... A> struct is_nothrow_invocable: std::false_type {};
+
+#else
+
+namespace detail {
+
+template<class F, class... A> struct is_nothrow_invocable_
+{
+    using type = std::integral_constant<bool, noexcept( compat::invoke( std::declval<F>(), std::declval<A>()... ) )>;
+};
+
+} // namespace detail
+
+template<class F, class... A> struct is_nothrow_invocable: conditional_t< is_invocable<F, A...>::value, detail::is_nothrow_invocable_<F, A...>, std::false_type >::type {};
+
+#endif
+
+// invoke_r
+
+template<class R, class F, class... A, class En = enable_if_t<
+    std::is_void<R>::value && is_invocable<F, A...>::value >>
+constexpr R invoke_r( F&& f, A&&... a )
+    noexcept( noexcept( static_cast<R>( compat::invoke( std::forward<F>(f), std::forward<A>(a)... ) ) ) )
+{
+    return static_cast<R>( compat::invoke( std::forward<F>(f), std::forward<A>(a)... ) );
+}
+
+template<class R, class F, class... A, class = void, class En = enable_if_t<
+    !std::is_void<R>::value && std::is_convertible< invoke_result_t<F, A...>, R >::value >>
+constexpr R invoke_r( F&& f, A&&... a )
+    noexcept( noexcept( static_cast<R>( compat::invoke( std::forward<F>(f), std::forward<A>(a)... ) ) ) )
+{
+    return compat::invoke( std::forward<F>(f), std::forward<A>(a)... );
+}
+
+// is_invocable_r
+
+namespace detail {
+
+template<class R, class F, class... A> struct is_invocable_r_: std::is_convertible< invoke_result_t<F, A...>, R > {};
+
+} // namespace detail
+
+template<class R, class F, class... A> struct is_invocable_r:
+    conditional_t< !is_invocable<F, A...>::value, std::false_type,
+    conditional_t< std::is_void<R>::value, std::true_type,
+    detail::is_invocable_r_<R, F, A...> >> {};
+
+// is_nothrow_invocable_r
+
+#if BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+template<class R, class F, class... A> struct is_nothrow_invocable_r: std::false_type {};
+
+#else
+
+namespace detail {
+
+template<class R, class F, class... A> struct is_nothrow_invocable_r_
+{
+    using type = std::integral_constant<bool, noexcept( compat::invoke_r<R>( std::declval<F>(), std::declval<A>()... ) )>;
+};
+
+} // namespace detail
+
+template<class R, class F, class... A> struct is_nothrow_invocable_r: conditional_t< is_invocable_r<R, F, A...>::value, detail::is_nothrow_invocable_r_<R, F, A...>, std::false_type >::type {};
+
+#endif
+
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_INVOKE_HPP_INCLUDED

include/boost/compat/mem_fn.hpp

@@ -0,0 +1,78 @@
+#ifndef BOOST_COMPAT_MEM_FN_HPP_INCLUDED
+#define BOOST_COMPAT_MEM_FN_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/type_traits.hpp>
+#include <boost/compat/detail/returns.hpp>
+#include <functional>
+
+namespace boost {
+namespace compat {
+
+namespace detail {
+
+template<class T, class U, class Td = remove_cvref_t<T>, class Ud = remove_cvref_t<U>>
+struct is_same_or_base: std::integral_constant<bool, std::is_same<Td, Ud>::value || std::is_base_of<Td, Ud>::value>
+{
+};
+
+template<class T> struct is_reference_wrapper_: std::false_type {};
+template<class T> struct is_reference_wrapper_< std::reference_wrapper<T> >: std::true_type {};
+
+template<class T> struct is_reference_wrapper: is_reference_wrapper_< remove_cvref_t<T> > {};
+
+template<class M, class T> struct _mfn
+{
+    M T::* pm_;
+
+    template<class U, class... A, class En = enable_if_t<is_same_or_base<T, U>::value>>
+    constexpr auto operator()( U&& u, A&&... a ) const
+    BOOST_COMPAT_RETURNS( (std::forward<U>(u).*pm_)( std::forward<A>(a)... ) )
+
+    template<class U, class... A, class = void, class En = enable_if_t< !is_same_or_base<T, U>::value && is_reference_wrapper<U>::value>>
+    constexpr auto operator()( U&& u, A&&... a ) const
+    BOOST_COMPAT_RETURNS( (u.get().*pm_)( std::forward<A>(a)... ) )
+
+    template<class U, class... A, class = void, class = void, class En = enable_if_t< !is_same_or_base<T, U>::value && !is_reference_wrapper<U>::value>>
+    constexpr auto operator()( U&& u, A&&... a ) const
+    BOOST_COMPAT_RETURNS( ((*std::forward<U>(u)).*pm_)( std::forward<A>(a)... ) )
+};
+
+template<class M, class T> struct _md
+{
+    M T::* pm_;
+
+    template<class U, class En = enable_if_t<is_same_or_base<T, U>::value>>
+    constexpr auto operator()( U&& u ) const
+    BOOST_COMPAT_RETURNS( std::forward<U>(u).*pm_ )
+
+    template<class U, class = void, class En = enable_if_t< !is_same_or_base<T, U>::value && is_reference_wrapper<U>::value>>
+    constexpr auto operator()( U&& u ) const
+    BOOST_COMPAT_RETURNS( u.get().*pm_ )
+
+    template<class U, class = void, class = void, class En = enable_if_t< !is_same_or_base<T, U>::value && !is_reference_wrapper<U>::value>>
+    constexpr auto operator()( U&& u ) const
+    BOOST_COMPAT_RETURNS( (*std::forward<U>(u)).*pm_ )
+};
+
+} // namespace detail
+
+template<class M, class T, class En = enable_if_t< std::is_function<M>::value > >
+constexpr auto mem_fn( M T::* pm ) noexcept -> detail::_mfn<M, T>
+{
+    return detail::_mfn<M, T>{ pm };
+}
+
+template<class M, class T, class = void, class En = enable_if_t< !std::is_function<M>::value > >
+constexpr auto mem_fn( M T::* pm ) noexcept -> detail::_md<M, T>
+{
+    return detail::_md<M, T>{ pm };
+}
+
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_MEM_FN_HPP_INCLUDED

include/boost/compat/type_traits.hpp

@@ -0,0 +1,41 @@
+#ifndef BOOST_COMPAT_TYPE_TRAITS_HPP_INCLUDED
+#define BOOST_COMPAT_TYPE_TRAITS_HPP_INCLUDED
+
+// Copyright 2024 Peter Dimov
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <type_traits>
+
+namespace boost {
+namespace compat {
+
+template<class T> using remove_const_t = typename std::remove_const<T>::type;
+template<class T> using remove_cv_t = typename std::remove_cv<T>::type;
+template<class T> using remove_reference_t = typename std::remove_reference<T>::type;
+template<class T> using remove_cvref_t = remove_cv_t< remove_reference_t<T> >;
+
+template<class T> using decay_t = typename std::decay<T>::type;
+
+template<bool B, class T = void> using enable_if_t = typename std::enable_if<B, T>::type;
+
+template<bool B, class T, class F> using conditional_t = typename std::conditional<B, T, F>::type;
+
+namespace detail {
+
+template<class...> struct make_void
+{
+    using type = void;
+};
+
+} // namespace detail
+
+template<class... T> using void_t = typename detail::make_void<T...>::type;
+
+template<class T> using add_const_t = typename std::add_const<T>::type;
+
+} // namespace compat
+} // namespace boost
+
+#endif // BOOST_COMPAT_TYPE_TRAITS_HPP_INCLUDED

meta/libraries.json

@@ -2,7 +2,8 @@
     "key": "compat",
     "name": "Compat",
     "authors": [
-        "Peter Dimov"
+        "Peter Dimov",
+        "Christian Mazakas"
     ],
     "maintainers": [
         "Peter Dimov <pdimov -at- gmail.com>"

test/CMakeLists.txt

@@ -8,6 +8,7 @@ if(HAVE_BOOST_TEST)
 
 set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
-boost_test_jamfile(FILE Jamfile LINK_LIBRARIES Boost::compat Boost::core Threads::Threads)
+
+boost_test_jamfile(FILE Jamfile LINK_LIBRARIES Boost::compat Boost::core Boost::mp11 Threads::Threads)
 
 endif()

test/Jamfile

@@ -4,7 +4,8 @@
 #  https://www.boost.org/LICENSE_1_0.txt
 
 import testing ;
-import ../../config/checks/config : requires ;
+import-search /boost/config/checks ;
+import config : requires ;
 
 project
   : default-build
@@ -20,10 +21,94 @@ project
     <toolset>msvc:<warnings-as-errors>on
     <toolset>gcc:<warnings-as-errors>on
     <toolset>clang:<warnings-as-errors>on
+
+    <library>/boost/core//boost_core
+    <library>/boost/mp11//boost_mp11
+
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81601
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91146
+    # https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92397
+    <toolset>gcc,<undefined-sanitizer>norecover:<cxxflags>"-Wno-array-bounds"
+    <toolset>gcc,<address-sanitizer>norecover:<cxxflags>"-Wno-array-bounds"
   ;
 
 run quick.cpp ;
 
 run latch_test.cpp ;
+
 run shared_lock_test.cpp ;
 run shared_lock_test.cpp : : : <exception-handling>off : shared_lock_test_nx ;
+
+run invoke_fn_test.cpp ;
+run invoke_obj_test.cpp ;
+run invoke_mfn_test.cpp ;
+run invoke_md_test.cpp ;
+
+run mem_fn_mfn_test.cpp ;
+run mem_fn_md_test.cpp ;
+
+run invoke_fn_noexcept_test.cpp ;
+run invoke_obj_noexcept_test.cpp ;
+run invoke_mfn_noexcept_test.cpp ;
+run invoke_md_noexcept_test.cpp ;
+
+compile invoke_fn_constexpr_test.cpp ;
+compile invoke_obj_constexpr_test.cpp ;
+compile invoke_mfn_constexpr_test.cpp
+  : <toolset>gcc-4.8:<build>no <toolset>gcc-4.9:<build>no ;
+compile invoke_md_constexpr_test.cpp
+  : <toolset>gcc-4.8:<build>no <toolset>gcc-4.9:<build>no ;
+
+run invoke_result_test.cpp ;
+run is_invocable_test.cpp ;
+run is_nothrow_invocable_test.cpp ;
+
+run bind_front_fn_test.cpp ;
+run bind_front_obj_test.cpp ;
+run bind_front_mfn_test.cpp ;
+run bind_front_md_test.cpp ;
+
+compile bind_front_fn_constexpr_test.cpp ;
+compile bind_front_obj_constexpr_test.cpp ;
+compile bind_front_mfn_constexpr_test.cpp ;
+compile bind_front_md_constexpr_test.cpp ;
+
+run integer_sequence_test.cpp ;
+
+run bind_back_fn_test.cpp ;
+run bind_back_obj_test.cpp ;
+run bind_back_mfn_test.cpp ;
+run bind_back_md_test.cpp ;
+
+compile bind_back_fn_constexpr_test.cpp ;
+compile bind_back_obj_constexpr_test.cpp ;
+compile bind_back_mfn_constexpr_test.cpp ;
+compile bind_back_md_constexpr_test.cpp ;
+
+run invoke_r_fn_test.cpp ;
+run invoke_r_obj_test.cpp ;
+run invoke_r_mfn_test.cpp ;
+run invoke_r_md_test.cpp ;
+
+run invoke_r_fn_noexcept_test.cpp ;
+run invoke_r_obj_noexcept_test.cpp ;
+run invoke_r_mfn_noexcept_test.cpp ;
+run invoke_r_md_noexcept_test.cpp ;
+
+compile invoke_r_fn_constexpr_test.cpp ;
+compile invoke_r_obj_constexpr_test.cpp ;
+compile invoke_r_mfn_constexpr_test.cpp
+  : <toolset>gcc-4.8:<build>no <toolset>gcc-4.9:<build>no ;
+compile invoke_r_md_constexpr_test.cpp
+  : <toolset>gcc-4.8:<build>no <toolset>gcc-4.9:<build>no ;
+
+run is_invocable_r_test.cpp ;
+run is_nothrow_invocable_r_test.cpp ;
+
+run function_ref_fn_test.cpp ;
+run function_ref_obj_test.cpp ;
+run function_ref_mfn_test.cpp ;
+
+run function_ref_fn_noexcept_test.cpp ;
+run function_ref_mfn_noexcept_test.cpp ;
+run function_ref_obj_noexcept_test.cpp ;

test/bind_back_fn_constexpr_test.cpp

@@ -0,0 +1,60 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+constexpr int f0()
+{
+    return -1;
+}
+
+constexpr int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+constexpr int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+constexpr int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::bind_back( f0 )(), -1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f1 )( 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f2 )( 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3 )( 1, 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f1, 1 )(), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f2, 1 )( 2 ), 21 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1 )( 2, 3 ), 231 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f2, 1, 2 )(), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1, 2 )( 3 ), 312 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1, 2, 3 )(), 123 );
+}
+
+#endif

test/bind_back_fn_test.cpp

@@ -0,0 +1,57 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <memory>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int g( std::unique_ptr<int> p, std::unique_ptr<int> q )
+{
+    return 10 * *p + *q;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::bind_back( f0 )(), -1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f1 )( 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f2 )( 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3 )( 1, 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f1, 1 )(), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f2, 1 )( 2 ), 21 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1 )( 2, 3 ), 231 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f2, 1, 2 )(), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1, 2 )( 3 ), 312 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( f3, 1, 2, 3 )(), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_back( g, std::unique_ptr<int>( new int(1) ) )( std::unique_ptr<int>( new int(2) ) ), 21 );
+
+    return boost::report_errors();
+}

test/bind_back_md_constexpr_test.cpp

@@ -0,0 +1,58 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, X() )(), -1 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &x )(), -1 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, >= 1920 && BOOST_MSVC < 1950)
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, Y() )(), -1 );
+    }
+
+    {
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &y )(), -1 );
+    }
+
+#endif
+}
+
+#endif

test/bind_back_md_test.cpp

@@ -0,0 +1,101 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, X() )(), -1 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, Y() )(), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, x )(), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &x )(), -1 );
+        boost::compat::bind_back( &X::m, &x )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &x )(), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(x) )(), -1 );
+        boost::compat::bind_back( &X::m, std::ref(x) )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(x) )(), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::cref(x) )(), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, y )(), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &y )(), -1 );
+        boost::compat::bind_back( &X::m, &y )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &y )(), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(y) )(), -1 );
+        boost::compat::bind_back( &X::m, std::ref(y) )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(y) )(), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::cref(y) )(), -1 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(x) )(), -1 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, &y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::m, std::ref(y) )(), -1 );
+    }
+
+    return boost::report_errors();
+}

test/bind_back_mfn_constexpr_test.cpp

@@ -0,0 +1,137 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    constexpr int f0()
+    {
+        return -1;
+    }
+
+    constexpr int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    constexpr int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( X() ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( X(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, X(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, X(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, X(), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( X() ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( X() ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( X() ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( Y() ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( Y(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, Y(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, Y(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, Y(), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( Y() ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( Y() ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( Y() ), 123 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        constexpr Y x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+
+    {
+        constexpr Y x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+}
+
+#endif

test/bind_back_mfn_test.cpp

@@ -0,0 +1,308 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+#include <memory>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( X() ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( X(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, X(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, X(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, X(), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( X() ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( X() ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( X() ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( Y() ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( Y(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, Y(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, Y(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, Y(), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( Y() ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( Y() ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( Y() ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( x ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( x ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( x ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( x ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( &x ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, &x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( &x ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( &x ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, &x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( &x ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( std::ref(x) ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, std::ref(x), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( std::ref(x) ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::ref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::ref(x) ), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f0 )( std::ref(x) ), -1 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1 )( std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, std::ref(x), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f1, 1 )( std::ref(x) ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::ref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::ref(x) ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::cref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::cref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::cref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::cref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::cref(x) ), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::cref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::cref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::cref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::cref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::cref(x) ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( x ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, &x, 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( &x ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( &x ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::ref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::ref(x) ), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f2, 1, 2 )( std::ref(x) ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::ref(x) ), 123 );
+    }
+
+    {
+        std::unique_ptr<X> px( new X );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::move(px) ), 123 );
+    }
+
+    {
+        std::unique_ptr<Y> px( new Y );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, 1, 2, 3 )( std::move(px) ), 123 );
+    }
+
+    {
+        std::unique_ptr<X> px( new X );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::move(px), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        std::unique_ptr<Y> px( new Y );
+        BOOST_TEST_EQ( boost::compat::bind_back( &X::f3, std::move(px), 1, 2, 3 )(), 123 );
+    }
+
+    return boost::report_errors();
+}

test/bind_back_obj_constexpr_test.cpp

@@ -0,0 +1,96 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct F1
+{
+    constexpr int operator()()
+    {
+        return -1;
+    }
+
+    constexpr int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct F2
+{
+    constexpr int operator()( int x1, int x2 ) &
+    {
+        return 100*x1 + 10*x2 + 1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const &
+    {
+        return 100*x1 + 10*x2 + 2;
+    }
+    constexpr int operator()( int x1, int x2 ) &&
+    {
+        return 100*x1 + 10*x2 + 3;
+    }
+    constexpr int operator()( int x1, int x2 ) const &&
+    {
+        return 100*x1 + 10*x2 + 4;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )( 2 ), 21 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )( 2, 3 ), 231 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2 )( 3 ), 312 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( F2(), 9 )( 8 ), 893 );
+    }
+
+    {
+        constexpr auto fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 892 );
+    }
+
+    {
+        constexpr auto fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 894 );
+    }
+}
+
+#endif

test/bind_back_obj_test.cpp

@@ -0,0 +1,101 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_back.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+struct F1
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct F2
+{
+    int operator()( int x1, int x2 ) &
+    {
+        return 100*x1 + 10*x2 + 1;
+    }
+
+    int operator()( int x1, int x2 ) const &
+    {
+        return 100*x1 + 10*x2 + 2;
+    }
+    int operator()( int x1, int x2 ) &&
+    {
+        return 100*x1 + 10*x2 + 3;
+    }
+    int operator()( int x1, int x2 ) const &&
+    {
+        return 100*x1 + 10*x2 + 4;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )( 2 ), 21 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1 )( 2, 3 ), 231 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2 )( 3 ), 312 );
+
+        BOOST_TEST_EQ( boost::compat::bind_back( F1(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_back( F2(), 9 )( 8 ), 893 );
+    }
+
+    {
+        auto fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 891 );
+    }
+
+    {
+        auto const fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 892 );
+    }
+
+    {
+        auto fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 893 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_GCC, < 40900)
+
+    {
+        auto const fn = boost::compat::bind_back( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 894 );
+    }
+
+#endif
+
+    return boost::report_errors();
+}

test/bind_front_fn_constexpr_test.cpp

@@ -0,0 +1,60 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+constexpr int f0()
+{
+    return -1;
+}
+
+constexpr int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+constexpr int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+constexpr int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::bind_front( f0 )(), -1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f1 )( 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f2 )( 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3 )( 1, 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f1, 1 )(), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f2, 1 )( 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1 )( 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f2, 1, 2 )(), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1, 2 )( 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1, 2, 3 )(), 123 );
+}
+
+#endif

test/bind_front_fn_test.cpp

@@ -0,0 +1,57 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <memory>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int g( std::unique_ptr<int> p, std::unique_ptr<int> q )
+{
+    return 10 * *p + *q;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::bind_front( f0 )(), -1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f1 )( 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f2 )( 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3 )( 1, 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f1, 1 )(), 1 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f2, 1 )( 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1 )( 2, 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f2, 1, 2 )(), 12 );
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1, 2 )( 3 ), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( f3, 1, 2, 3 )(), 123 );
+
+    BOOST_TEST_EQ( boost::compat::bind_front( g, std::unique_ptr<int>( new int(1) ) )( std::unique_ptr<int>( new int(2) ) ), 12 );
+
+    return boost::report_errors();
+}

test/bind_front_md_constexpr_test.cpp

@@ -0,0 +1,58 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, X() )(), -1 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &x )(), -1 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, >= 1920 && BOOST_MSVC < 1950)
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, Y() )(), -1 );
+    }
+
+    {
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &y )(), -1 );
+    }
+
+#endif
+}
+
+#endif

test/bind_front_md_test.cpp

@@ -0,0 +1,101 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, X() )(), -1 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, Y() )(), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, x )(), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &x )(), -1 );
+        boost::compat::bind_front( &X::m, &x )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &x )(), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(x) )(), -1 );
+        boost::compat::bind_front( &X::m, std::ref(x) )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(x) )(), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::cref(x) )(), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, y )(), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &y )(), -1 );
+        boost::compat::bind_front( &X::m, &y )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &y )(), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(y) )(), -1 );
+        boost::compat::bind_front( &X::m, std::ref(y) )() = +1;
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(y) )(), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::cref(y) )(), -1 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(x) )(), -1 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, &y )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::m, std::ref(y) )(), -1 );
+    }
+
+    return boost::report_errors();
+}

test/bind_front_mfn_constexpr_test.cpp

@@ -0,0 +1,167 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    constexpr int f0()
+    {
+        return -1;
+    }
+
+    constexpr int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    constexpr int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( X(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, X() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, X() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, X(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, Y() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, Y() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        constexpr Y x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        constexpr Y x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+}
+
+#endif

test/bind_front_mfn_test.cpp

@@ -0,0 +1,378 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+#include <memory>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( X(), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, X() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, X() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, X(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, X(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, X(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, Y() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, Y() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, Y(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, Y(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, Y(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( x ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, x )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, &x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, &x )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, &x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, std::ref(x) )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, std::ref(x) )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, std::ref(x), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::cref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( x ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, x )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, &x )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, &x )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, &x, 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0 )( std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1 )( std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f0, std::ref(x) )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, std::ref(x) )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f1, std::ref(x), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y x;
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::cref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::cref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::cref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, &x, 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, &x, 1, 2, 3 )(), 123 );
+    }
+
+    {
+        Y const x = {};
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x) )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x) )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f2, std::ref(x), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::ref(x), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        std::unique_ptr<X> px( new X );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::move(px), 1 )( 2, 3 ), 123 );
+    }
+
+    {
+        std::unique_ptr<Y> px( new Y );
+        BOOST_TEST_EQ( boost::compat::bind_front( &X::f3, std::move(px), 1 )( 2, 3 ), 123 );
+    }
+
+    return boost::report_errors();
+}

test/bind_front_obj_constexpr_test.cpp

@@ -0,0 +1,96 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+
+#if defined(BOOST_NO_CXX14_CONSTEXPR)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped because BOOST_NO_CXX14_CONSTEXPR is defined" )
+int main() {}
+
+#else
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct F1
+{
+    constexpr int operator()()
+    {
+        return -1;
+    }
+
+    constexpr int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct F2
+{
+    constexpr int operator()( int x1, int x2 ) &
+    {
+        return 100*x1 + 10*x2 + 1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const &
+    {
+        return 100*x1 + 10*x2 + 2;
+    }
+    constexpr int operator()( int x1, int x2 ) &&
+    {
+        return 100*x1 + 10*x2 + 3;
+    }
+    constexpr int operator()( int x1, int x2 ) const &&
+    {
+        return 100*x1 + 10*x2 + 4;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( F2(), 9 )( 8 ), 983 );
+    }
+
+    {
+        constexpr auto fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 982 );
+    }
+
+    {
+        constexpr auto fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 984 );
+    }
+}
+
+#endif

test/bind_front_obj_test.cpp

@@ -0,0 +1,101 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/bind_front.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+struct F1
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct F2
+{
+    int operator()( int x1, int x2 ) &
+    {
+        return 100*x1 + 10*x2 + 1;
+    }
+
+    int operator()( int x1, int x2 ) const &
+    {
+        return 100*x1 + 10*x2 + 2;
+    }
+    int operator()( int x1, int x2 ) &&
+    {
+        return 100*x1 + 10*x2 + 3;
+    }
+    int operator()( int x1, int x2 ) const &&
+    {
+        return 100*x1 + 10*x2 + 4;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )(), -1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1() )( 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )(), 1 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )( 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1 )( 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2 )(), 12 );
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2 )( 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::bind_front( F1(), 1, 2, 3 )(), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::bind_front( F2(), 9 )( 8 ), 983 );
+    }
+
+    {
+        auto fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 981 );
+    }
+
+    {
+        auto const fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( fn( 8 ), 982 );
+    }
+
+    {
+        auto fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 983 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_GCC, < 40900)
+
+    {
+        auto const fn = boost::compat::bind_front( F2(), 9 );
+        BOOST_TEST_EQ( std::move( fn )( 8 ), 984 );
+    }
+
+#endif
+
+    return boost::report_errors();
+}

test/cmake_install_test/CMakeLists.txt

@@ -14,4 +14,4 @@ target_link_libraries(quick Boost::compat)
 enable_testing()
 add_test(quick quick)
 
-add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)
+add_custom_target(check VERBATIM COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/cmake_subdir_test/CMakeLists.txt

@@ -18,4 +18,4 @@ target_link_libraries(quick Boost::compat)
 enable_testing()
 add_test(quick quick)
 
-add_custom_target(check COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)
+add_custom_target(check VERBATIM COMMAND ${CMAKE_CTEST_COMMAND} --output-on-failure -C $<CONFIG>)

test/function_ref_fn_noexcept_test.cpp

@@ -0,0 +1,165 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE("Test skipped, __cpp_noexcept_function_type is not defined")
+int main() {}
+
+#else
+
+#include <boost/compat/function_ref.hpp>
+#include <boost/config.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+int f0() { return -1; }
+
+int f1(int x1) noexcept { return x1; }
+int g1(int x1) noexcept { return x1 * 2; }
+
+int f2(int x1, int x2) { return 10 * x1 + x2; }
+
+int f3(int x1, int x2, int x3) noexcept { return 100 * x1 + 10 * x2 + x3; }
+
+int g(std::unique_ptr<int> p, std::unique_ptr<int> q) { return 10 * *p + *q; }
+
+struct X {
+  int v = 0;
+
+  X() = default;
+  X(int v_) noexcept : v{v_} {}
+};
+
+struct Y {
+  int v = 0;
+
+  Y() = default;
+  explicit Y(int v_) : v{v_} {}
+};
+
+struct Z {
+  int v = 0;
+
+  Z() = default;
+  Z(int v_) : v{v_} {}
+};
+
+namespace compat = boost::compat;
+
+int main() {
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int() noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int() const noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int) noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int) const noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int) noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int) const noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int, int) noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int, int) const noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<X(int, int, int) noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<X(int, int, int) const noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<void(int, int, int) noexcept>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<void(int, int, int) const noexcept>>));
+
+  struct W {
+    int w_;
+  };
+
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int() noexcept>, W>));
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int() const noexcept>, W>));
+
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int() noexcept>, compat::function_ref<int()>>));
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int()>, compat::function_ref<int() noexcept>>));
+  BOOST_TEST_TRAIT_FALSE(
+      (std::is_assignable<compat::function_ref<int() const noexcept>, compat::function_ref<int() const>>));
+
+  BOOST_TEST_TRAIT_FALSE(
+      (std::is_assignable<compat::function_ref<int() noexcept>, compat::function_ref<int(int) noexcept>>));
+  BOOST_TEST_TRAIT_FALSE(
+      (std::is_assignable<compat::function_ref<int(int) noexcept>, compat::function_ref<int() noexcept>>));
+
+  // f0
+  {
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int() noexcept>, decltype(f0)>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int() const noexcept>, decltype(f0)>));
+  }
+
+  // f1
+  {
+    compat::function_ref<int(int) noexcept> fv1(f1);
+    BOOST_TEST_EQ(fv1(1), 1);
+
+    compat::function_ref<int(int) const noexcept> fv2(f1);
+    BOOST_TEST_EQ(fv2(1), 1);
+  }
+
+  // f2
+  {
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int, int) noexcept>, decltype(f2)>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int, int) const noexcept>, decltype(f2)>));
+  }
+
+  // f3
+  {
+    compat::function_ref<int(int, int, int) noexcept> fv1(f3);
+    BOOST_TEST_EQ(fv1(1, 2, 3), 123);
+
+    compat::function_ref<int(int, int, int) const noexcept> fv2(f3);
+    BOOST_TEST_EQ(fv2(1, 2, 3), 123);
+  }
+
+  // g
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(std::unique_ptr<int>, std::unique_ptr<int>) noexcept>,
+                               decltype(g)>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(std::unique_ptr<int>, std::unique_ptr<int>) const noexcept>,
+                               decltype(g)>));
+  }
+
+  // invoke_r
+  {
+    compat::function_ref<X(int, int, int) noexcept> fv1(f3);
+    BOOST_TEST_EQ(fv1(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int) noexcept>, decltype(f3)>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Z(int, int, int) noexcept>, decltype(f3)>));
+
+    compat::function_ref<X(int, int, int) const noexcept> fv2(f3);
+    BOOST_TEST_EQ(fv2(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<Y(int, int, int) const noexcept>, decltype(f3)>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<Z(int, int, int) const noexcept>, decltype(f3)>));
+
+    compat::function_ref<void(int, int, int) noexcept> fv3(f3);
+    fv3(1, 2, 3);
+
+    compat::function_ref<void(int, int, int) const noexcept> fv4(f3);
+    fv4(1, 2, 3);
+  }
+
+  // copy construct, copy assign
+  {
+    compat::function_ref<int(int) noexcept> fv(f1);
+    compat::function_ref<int(int) noexcept> fv2(fv);
+    BOOST_TEST_EQ(fv(42), fv2(42));
+
+    fv2 = g1;
+    BOOST_TEST_EQ(fv2(12), 24);
+
+    compat::function_ref<int(int) const noexcept> cfv(f1);
+    compat::function_ref<int(int) const noexcept> cfv2(cfv);
+    BOOST_TEST_EQ(cfv(42), cfv2(42));
+
+    cfv2 = g1;
+    BOOST_TEST_EQ(cfv2(24), 48);
+  }
+
+  return boost::report_errors();
+}
+
+#endif

test/function_ref_fn_test.cpp

@@ -0,0 +1,183 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+#pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/function_ref.hpp>
+
+#include <boost/config.hpp>
+#include <boost/config/pragma_message.hpp>
+#include <boost/config/workaround.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+int f0() { return -1; }
+int g0() { return 7331; }
+
+int f1(int x1) noexcept { return x1; }
+
+int f2(int x1, int x2) { return 10 * x1 + x2; }
+
+int f3(int x1, int x2, int x3) noexcept { return 100 * x1 + 10 * x2 + x3; }
+
+int g(std::unique_ptr<int> p, std::unique_ptr<int> q) { return 10 * *p + *q; }
+
+struct X {
+  int v = 0;
+
+  X() = default;
+  X(int v_) noexcept : v{v_} {}
+};
+
+struct Y {
+  int v = 0;
+
+  Y() = default;
+  explicit Y(int v_) : v{v_} {}
+};
+
+struct Z {
+  int v = 0;
+
+  Z() = default;
+  Z(int v_) : v{v_} {}
+};
+
+namespace compat = boost::compat;
+
+int main() {
+
+#if !defined(BOOST_NO_CXX11_HDR_TYPE_TRAITS)
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int()>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int() const>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int)>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int) const>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int)>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int) const>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int, int)>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<int(int, int, int) const>>));
+  BOOST_TEST_TRAIT_TRUE(
+      (std::is_trivially_copyable<compat::function_ref<int(std::unique_ptr<int>, std::unique_ptr<int>)>>));
+  BOOST_TEST_TRAIT_TRUE(
+      (std::is_trivially_copyable<compat::function_ref<int(std::unique_ptr<int>, std::unique_ptr<int>) const>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<X(int, int, int)>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<X(int, int, int) const>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<void(int, int, int)>>));
+  BOOST_TEST_TRAIT_TRUE((std::is_trivially_copyable<compat::function_ref<void(int, int, int) const>>));
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+  struct W {
+    int w_;
+  };
+
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int()>, W>));
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int() const>, W>));
+
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int()>, compat::function_ref<int() const>>));
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int() const>, compat::function_ref<int()>>));
+
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int()>, compat::function_ref<int(int)>>));
+  BOOST_TEST_TRAIT_FALSE((std::is_assignable<compat::function_ref<int(int)>, compat::function_ref<int()>>));
+#endif
+
+#else
+  BOOST_PRAGMA_MESSAGE("<type_traits> is incomplete, skipping is_trivially_copyable checks")
+#endif
+
+  // f0
+  {
+    compat::function_ref<int()> fv1(f0);
+    BOOST_TEST_EQ(fv1(), -1);
+
+    compat::function_ref<int() const> fv2(f0);
+    BOOST_TEST_EQ(fv2(), -1);
+  }
+
+  // f1
+  {
+    compat::function_ref<int(int)> fv1(f1);
+    BOOST_TEST_EQ(fv1(1), 1);
+
+    compat::function_ref<int(int) const> fv2(f1);
+    BOOST_TEST_EQ(fv2(1), 1);
+  }
+
+  // f2
+  {
+    compat::function_ref<int(int, int)> fv1(f2);
+    BOOST_TEST_EQ(fv1(1, 2), 12);
+
+    compat::function_ref<int(int, int) const> fv2(f2);
+    BOOST_TEST_EQ(fv2(1, 2), 12);
+  }
+
+  // f3
+  {
+    compat::function_ref<int(int, int, int)> fv1(f3);
+    BOOST_TEST_EQ(fv1(1, 2, 3), 123);
+
+    compat::function_ref<int(int, int, int) const> fv2(f3);
+    BOOST_TEST_EQ(fv2(1, 2, 3), 123);
+  }
+
+  // g
+  {
+    using S1 = int(std::unique_ptr<int>, std::unique_ptr<int>);
+    using S2 = int(std::unique_ptr<int>, std::unique_ptr<int>) const;
+
+    compat::function_ref<S1> fv1(g);
+    {
+      auto p = std::unique_ptr<int>(new int{1});
+      auto q = std::unique_ptr<int>(new int{2});
+      BOOST_TEST_EQ(fv1(std::move(p), std::move(q)), 12);
+    }
+
+    compat::function_ref<S2> fv2(g);
+    {
+      auto p = std::unique_ptr<int>(new int{130});
+      auto q = std::unique_ptr<int>(new int{37});
+      BOOST_TEST_EQ(fv1(std::move(p), std::move(q)), 1337);
+    }
+  }
+
+  // invoke_r
+  {
+    compat::function_ref<X(int, int, int)> fv1(f3);
+    BOOST_TEST_EQ(fv1(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int)>, decltype(f3)>));
+    BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<Z(int, int, int)>, decltype(f3)>));
+
+    compat::function_ref<X(int, int, int) const> fv2(f3);
+    BOOST_TEST_EQ(fv2(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int) const>, decltype(f3)>));
+    BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<Z(int, int, int) const>, decltype(f3)>));
+
+    compat::function_ref<void(int, int, int)> fv3(f3);
+    fv3(1, 2, 3);
+
+    compat::function_ref<void(int, int, int) const> fv4(f3);
+    fv4(1, 2, 3);
+  }
+
+  // copy construct, copy assign
+  {
+    compat::function_ref<int()> fv(f0);
+    compat::function_ref<int()> fv2(fv);
+    BOOST_TEST_EQ(fv(), fv2());
+
+    fv2 = g0;
+    BOOST_TEST_EQ(fv2(), 7331);
+
+    compat::function_ref<int() const> cfv(f0);
+    compat::function_ref<int() const> cfv2(cfv);
+    BOOST_TEST_EQ(cfv(), cfv2());
+
+    cfv2 = g0;
+    BOOST_TEST_EQ(cfv2(), 7331);
+  }
+
+  return boost::report_errors();
+}

test/function_ref_mfn_noexcept_test.cpp

@@ -0,0 +1,164 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+#pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/function_ref.hpp>
+
+#if !defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+#include <boost/config/pragma_message.hpp>
+BOOST_PRAGMA_MESSAGE("no support for placeholder NTTPs detected, skipping this test")
+int main() {}
+#else
+
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+#include <memory>
+#include <type_traits>
+
+struct F1 {
+  std::unique_ptr<int> p_;
+
+  F1() : p_(new int(1)) {}
+
+  int m1() { return *p_ + -1; }
+  int m2(int x1) noexcept { return 10 * *p_ + x1; }
+  int m3(int x1, int x2) const { return 100 * *p_ + 10 * x1 + x2; }
+  int m4(int x1, int x2, int x3) const noexcept { return 1000 * *p_ + 100 * x1 + 10 * x2 + x3; }
+};
+
+namespace compat = boost::compat;
+
+int main() {
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1&) noexcept>, compat::nontype_t<&F1::m1>>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(F1&, int) noexcept>, compat::nontype_t<&F1::m2>>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1&, int, int) noexcept>, compat::nontype_t<&F1::m3>>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(F1&, int, int, int) noexcept>, compat::nontype_t<&F1::m4>>));
+  }
+
+  {
+    F1 f1;
+
+    compat::function_ref<int(F1&, int) noexcept> fn2(compat::nontype_t<&F1::m2>{});
+    BOOST_TEST_EQ(fn2(f1, 2), 12);
+
+    compat::function_ref<int(F1&, int, int, int) noexcept> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1&) const noexcept>, compat::nontype_t<&F1::m1>>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1&, int, int) const noexcept>, compat::nontype_t<&F1::m3>>));
+
+    F1 f1;
+
+    compat::function_ref<int(F1&, int) const noexcept> fn2(compat::nontype_t<&F1::m2>{});
+    BOOST_TEST_EQ(fn2(f1, 2), 12);
+
+    compat::function_ref<int(F1&, int, int, int) const noexcept> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1 const&) noexcept>, compat::nontype_t<&F1::m1>>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1 const&, int) noexcept>, compat::nontype_t<&F1::m2>>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1 const&, int, int) noexcept>, compat::nontype_t<&F1::m3>>));
+
+    F1 f1;
+
+    compat::function_ref<int(F1 const&, int, int, int) noexcept> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int() noexcept>, compat::nontype_t<&F1::m1>, F1&>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int) noexcept>, compat::nontype_t<&F1::m2>, F1&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int, int) noexcept>, compat::nontype_t<&F1::m3>, F1&>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int, int, int) noexcept>, compat::nontype_t<&F1::m4>, F1&>));
+
+    F1 f1;
+
+    compat::function_ref<int(int) noexcept> fn2(compat::nontype_t<&F1::m2>{}, f1);
+    BOOST_TEST_EQ(fn2(2), 12);
+
+    compat::function_ref<int(int, int, int) noexcept> fn4(compat::nontype_t<&F1::m4>{}, f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int() const noexcept>, compat::nontype_t<&F1::m1>, F1 const&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int) const noexcept>, compat::nontype_t<&F1::m2>, F1 const&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int, int) const noexcept>,
+                                                  compat::nontype_t<&F1::m3>, F1 const&>));
+
+    F1 f1;
+
+    compat::function_ref<int(int, int, int) const noexcept> fn4(compat::nontype_t<&F1::m4>{}, f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+
+    auto const& f1_2 = f1;
+    compat::function_ref<int(int, int, int) const noexcept> fn4_2(compat::nontype_t<&F1::m4>{}, f1_2);
+    BOOST_TEST_EQ(fn4_2(2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int() noexcept>, compat::nontype_t<&F1::m1>, F1*>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int) noexcept>, compat::nontype_t<&F1::m2>, F1*>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int, int) noexcept>, compat::nontype_t<&F1::m3>, F1*>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int, int, int) noexcept>, compat::nontype_t<&F1::m4>, F1*>));
+
+    F1 f1;
+
+    compat::function_ref<int(int) noexcept> fn2(compat::nontype_t<&F1::m2>{}, &f1);
+    BOOST_TEST_EQ(fn2(2), 12);
+
+    compat::function_ref<int(int, int, int) noexcept> fn4(compat::nontype_t<&F1::m4>{}, &f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int() const noexcept>, compat::nontype_t<&F1::m1>, F1 const*>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int) const noexcept>, compat::nontype_t<&F1::m2>, F1 const*>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int, int) const noexcept>,
+                                                  compat::nontype_t<&F1::m3>, F1 const*>));
+
+    F1 const f1;
+
+    compat::function_ref<int(int, int, int) const noexcept> fn4(compat::nontype_t<&F1::m4>{}, &f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+
+    auto const& f1_2 = f1;
+    compat::function_ref<int(int, int, int) const noexcept> fn4_2(compat::nontype_t<&F1::m4>{}, &f1_2);
+    BOOST_TEST_EQ(fn4_2(2, 3, 4), 1234);
+  }
+
+  return boost::report_errors();
+}
+
+#endif

test/function_ref_mfn_test.cpp

@@ -0,0 +1,176 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+#pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/function_ref.hpp>
+
+#if !defined(BOOST_COMPAT_HAS_AUTO_NTTP)
+#include <boost/config/pragma_message.hpp>
+BOOST_PRAGMA_MESSAGE("no support for placeholder NTTPs detected, skipping this test")
+int main() {}
+#else
+
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+#include <memory>
+#include <type_traits>
+
+struct F1 {
+  std::unique_ptr<int> p_;
+  int q_ = 1337;
+
+  F1() : p_(new int(1)) {}
+
+  int m1() { return *p_ + -1; }
+  int m2(int x1) noexcept { return 10 * *p_ + x1; }
+  int m3(int x1, int x2) const { return 100 * *p_ + 10 * x1 + x2; }
+  int m4(int x1, int x2, int x3) const noexcept { return 1000 * *p_ + 100 * x1 + 10 * x2 + x3; }
+};
+
+namespace compat = boost::compat;
+
+int main() {
+  {
+    F1 f1;
+
+    compat::function_ref<int(F1&)> fn1(compat::nontype_t<&F1::m1>{});
+    BOOST_TEST_EQ(fn1(f1), 0);
+
+    compat::function_ref<int(F1&, int)> fn2(compat::nontype_t<&F1::m2>{});
+    BOOST_TEST_EQ(fn2(f1, 2), 12);
+
+    compat::function_ref<int(F1&, int, int)> fn3(compat::nontype_t<&F1::m3>{});
+    BOOST_TEST_EQ(fn3(f1, 2, 3), 123);
+
+    compat::function_ref<int(F1&, int, int, int)> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+
+    compat::function_ref<int(F1&)> a1(compat::nontype_t<&F1::q_>{});
+    BOOST_TEST_EQ(a1(f1), 1337);
+  }
+
+  {
+    F1 f1;
+
+    compat::function_ref<int(F1&) const> fn1(compat::nontype_t<&F1::m1>{});
+    BOOST_TEST_EQ(fn1(f1), 0);
+
+    compat::function_ref<int(F1&, int) const> fn2(compat::nontype_t<&F1::m2>{});
+    BOOST_TEST_EQ(fn2(f1, 2), 12);
+
+    compat::function_ref<int(F1&, int, int) const> fn3(compat::nontype_t<&F1::m3>{});
+    BOOST_TEST_EQ(fn3(f1, 2, 3), 123);
+
+    compat::function_ref<int(F1&, int, int, int) const> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(F1 const&)>, compat::nontype_t<&F1::m1>>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(F1 const&, int)>, compat::nontype_t<&F1::m2>>));
+
+    F1 f1;
+
+    compat::function_ref<int(F1 const&, int, int) const> fn3(compat::nontype_t<&F1::m3>{});
+    BOOST_TEST_EQ(fn3(f1, 2, 3), 123);
+
+    compat::function_ref<int(F1 const&, int, int, int) const> fn4(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f1, 2, 3, 4), 1234);
+
+    auto const& f2 = f1;
+
+    compat::function_ref<int(F1 const&, int, int) const> fn23(compat::nontype_t<&F1::m3>{});
+    BOOST_TEST_EQ(fn3(f2, 2, 3), 123);
+
+    compat::function_ref<int(F1 const&, int, int, int) const> fn24(compat::nontype_t<&F1::m4>{});
+    BOOST_TEST_EQ(fn4(f2, 2, 3, 4), 1234);
+  }
+
+  {
+    BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<int(int)>, compat::nontype_t<&F1::m2>, F1&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int)>, compat::nontype_t<&F1::m2>, F1 const&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int)>, compat::nontype_t<&F1::m2>, F1&&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int(int)>, compat::nontype_t<&F1::m2>, F1>));
+
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int, int) const>, compat::nontype_t<&F1::m3>, F1&>));
+    BOOST_TEST_TRAIT_TRUE(
+        (std::is_constructible<compat::function_ref<int(int, int) const>, compat::nontype_t<&F1::m3>, F1 const&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int, int) const>, compat::nontype_t<&F1::m3>, F1&&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int, int) const>, compat::nontype_t<&F1::m3>, F1>));
+  }
+
+  {
+    F1 f1;
+
+    compat::function_ref<int()> fn1(compat::nontype_t<&F1::m1>{}, f1);
+    BOOST_TEST_EQ(fn1(), 0);
+
+    compat::function_ref<int(int)> fn2(compat::nontype_t<&F1::m2>{}, f1);
+    BOOST_TEST_EQ(fn2(2), 12);
+
+    compat::function_ref<int(int, int)> fn3(compat::nontype_t<&F1::m3>{}, f1);
+    BOOST_TEST_EQ(fn3(2, 3), 123);
+
+    compat::function_ref<int(int, int, int)> fn4(compat::nontype_t<&F1::m4>{}, f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  {
+    F1 const f1;
+
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<int() const>, compat::nontype_t<&F1::m1>, F1&>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int) const>, compat::nontype_t<&F1::m2>, F1&>));
+
+    compat::function_ref<int(int, int) const> fn3(compat::nontype_t<&F1::m3>{}, f1);
+    BOOST_TEST_EQ(fn3(2, 3), 123);
+
+    compat::function_ref<int(int, int, int) const> fn4(compat::nontype_t<&F1::m4>{}, f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  {
+    F1 f1;
+
+    compat::function_ref<int()> fn1(compat::nontype_t<&F1::m1>{}, &f1);
+    BOOST_TEST_EQ(fn1(), 0);
+
+    compat::function_ref<int(int)> fn2(compat::nontype_t<&F1::m2>{}, &f1);
+    BOOST_TEST_EQ(fn2(2), 12);
+
+    compat::function_ref<int(int, int)> fn3(compat::nontype_t<&F1::m3>{}, &f1);
+    BOOST_TEST_EQ(fn3(2, 3), 123);
+
+    compat::function_ref<int(int, int, int)> fn4(compat::nontype_t<&F1::m4>{}, &f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  {
+    F1 const f1;
+
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int() const>, compat::nontype_t<&F1::m1>, F1 const*>));
+    BOOST_TEST_TRAIT_FALSE(
+        (std::is_constructible<compat::function_ref<int(int) const>, compat::nontype_t<&F1::m2>, F1 const*>));
+
+    compat::function_ref<int(int, int) const> fn3(compat::nontype_t<&F1::m3>{}, &f1);
+    BOOST_TEST_EQ(fn3(2, 3), 123);
+
+    compat::function_ref<int(int, int, int) const> fn4(compat::nontype_t<&F1::m4>{}, &f1);
+    BOOST_TEST_EQ(fn4(2, 3, 4), 1234);
+  }
+
+  return boost::report_errors();
+}
+
+#endif

test/function_ref_obj_noexcept_test.cpp

@@ -0,0 +1,228 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE("Test skipped, __cpp_noexcept_function_type is not defined")
+int main() {}
+
+#else
+
+#include <boost/compat/function_ref.hpp>
+#include <boost/config.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct F1 {
+  int operator()() { return -1; }
+
+  int operator()(int x1) noexcept { return x1; }
+
+  int operator()(int x1, int x2) const { return 10 * x1 + x2; }
+
+  int operator()(int x1, int x2, int x3) const noexcept { return 100 * x1 + 10 * x2 + x3; }
+};
+
+struct F2 {
+  int operator()(int x1, int x2) & { return 100 * x1 + 10 * x2 + 1; }
+  int operator()(int x1, int x2) const& { return 100 * x1 + 10 * x2 + 2; }
+  int operator()(int x1, int x2) && { return 100 * x1 + 10 * x2 + 3; }
+  int operator()(int x1, int x2) const&& { return 100 * x1 + 10 * x2 + 4; }
+};
+
+struct X {
+  int v = 0;
+
+  X() = default;
+  X(int v_) noexcept : v{v_} {}
+};
+
+struct Y {
+  int v = 0;
+
+  Y() = default;
+  explicit Y(int v_) : v{v_} {}
+};
+
+struct Z {
+  int v = 0;
+
+  Z() = default;
+  Z(int v_) : v{v_} {}
+};
+
+namespace compat = boost::compat;
+
+int main() {
+  {
+    F1 f1;
+    {
+      using S1 = int() noexcept;
+      using S2 = int(int) noexcept;
+      using S3 = int(int, int) noexcept;
+      using S4 = int(int, int, int) noexcept;
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&&>));
+
+      compat::function_ref<S2> fv2(f1);
+
+      BOOST_TEST_EQ(fv2(1), 1);
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&&>));
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const&&>));
+
+      compat::function_ref<S4> fv4(f1);
+
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&&>));
+    }
+    {
+      using S1 = int() const noexcept;
+      using S2 = int(int) const noexcept;
+      using S3 = int(int, int) const noexcept;
+      using S4 = int(int, int, int) const noexcept;
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&&>));
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&&>));
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S3>, F1 const&&>));
+
+      compat::function_ref<S4> fv4(f1);
+
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&&>));
+    }
+
+    {
+      using S2 = int(int) noexcept;
+      using S4 = int(int, int, int) noexcept;
+
+      auto& fref = f1;
+
+      compat::function_ref<S2> fv2(fref);
+      BOOST_TEST_EQ(fv2(1), 1);
+
+      auto const& cfref = f1;
+      compat::function_ref<S4> fv4(cfref);
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+    }
+
+    {
+      using S4 = int(int, int, int) const noexcept;
+
+      auto const& cfref = f1;
+      compat::function_ref<S4> fv4(cfref);
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+    }
+  }
+
+  {
+    using S1 = int(int, int) noexcept;
+    using S2 = int(int, int) const noexcept;
+
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2&&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2 const>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2 const&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F2 const&&>));
+
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2&&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2 const>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2 const&>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F2 const&&>));
+  }
+
+  // invoke_r
+  {
+    F1 f;
+
+    compat::function_ref<X(int, int, int) noexcept> fv1(f);
+    BOOST_TEST_EQ(fv1(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int) noexcept>, F1>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Z(int, int, int) noexcept>, F1>));
+
+    compat::function_ref<X(int, int, int) const noexcept> fv2(f);
+    BOOST_TEST_EQ(fv2(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int) const noexcept>, F1>));
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Z(int, int, int) const noexcept>, F1>));
+
+    compat::function_ref<void(int, int, int) noexcept> fv3(f);
+    fv3(1, 2, 3);
+
+    compat::function_ref<void(int, int, int) const noexcept> fv4(f);
+    fv4(1, 2, 3);
+  }
+
+  // copy construct, copy assign
+  {
+    F1 f;
+
+    auto id = [](int x) noexcept { return x + 7331; };
+
+    compat::function_ref<int(int) noexcept> fv(f);
+    compat::function_ref<int(int) noexcept> fv2(fv);
+    BOOST_TEST_EQ(fv(12), fv2(12));
+
+    fv2 = compat::function_ref<int(int) noexcept>(id);
+    BOOST_TEST_EQ(fv2(1), 7332);
+
+    auto add = [](int x, int y, int z) noexcept { return x + y + z; };
+    compat::function_ref<int(int, int, int) const noexcept> cfv(f);
+    compat::function_ref<int(int, int, int) const noexcept> cfv2(cfv);
+    BOOST_TEST_EQ(cfv(1, 2, 3), cfv2(1, 2, 3));
+
+    cfv2 = compat::function_ref<int(int, int, int) const noexcept>(add);
+    BOOST_TEST_EQ(cfv2(1, 2, 3), 6);
+  }
+
+  return boost::report_errors();
+}
+
+#endif

test/function_ref_obj_test.cpp

@@ -0,0 +1,260 @@
+// Copyright 2024 Christian Mazakas
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/function_ref.hpp>
+#include <boost/config.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct F1 {
+  int operator()() { return -1; }
+
+  int operator()(int x1) noexcept { return x1; }
+
+  int operator()(int x1, int x2) const { return 10 * x1 + x2; }
+
+  int operator()(int x1, int x2, int x3) const noexcept { return 100 * x1 + 10 * x2 + x3; }
+};
+
+struct F2 {
+  int operator()(int x1, int x2) & { return 100 * x1 + 10 * x2 + 1; }
+  int operator()(int x1, int x2) const& { return 100 * x1 + 10 * x2 + 2; }
+  int operator()(int x1, int x2) && { return 100 * x1 + 10 * x2 + 3; }
+  int operator()(int x1, int x2) const&& { return 100 * x1 + 10 * x2 + 4; }
+};
+
+struct X {
+  int v = 0;
+
+  X() = default;
+  X(int v_) noexcept : v{v_} {}
+};
+
+struct Y {
+  int v = 0;
+
+  Y() = default;
+  explicit Y(int v_) : v{v_} {}
+};
+
+struct Z {
+  int v = 0;
+
+  Z() = default;
+  Z(int v_) : v{v_} {}
+};
+
+namespace compat = boost::compat;
+
+int main() {
+  {
+    F1 f;
+    {
+      using S1 = int();
+      using S2 = int(int);
+      using S3 = int(int, int);
+      using S4 = int(int, int, int);
+
+      compat::function_ref<S1> fv1(f);
+
+      BOOST_TEST_EQ(fv1(), -1);
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&&>));
+
+      compat::function_ref<S2> fv2(f);
+
+      BOOST_TEST_EQ(fv2(1), 1);
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&>));
+
+      compat::function_ref<S3> fv3(f);
+
+      BOOST_TEST_EQ(fv3(1, 2), 12);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const&&>));
+
+      compat::function_ref<S4> fv4(f);
+
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&&>));
+    }
+
+    {
+      using S1 = int() const;
+      using S2 = int(int) const;
+      using S3 = int(int, int) const;
+      using S4 = int(int, int, int) const;
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S1>, F1 const&&>));
+
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1&&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&>));
+      BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<S2>, F1 const&&>));
+
+      compat::function_ref<S3> fv3(f);
+
+      BOOST_TEST_EQ(fv3(1, 2), 12);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S3>, F1 const&&>));
+
+      compat::function_ref<S4> fv4(f);
+
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1&&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&>));
+      BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<S4>, F1 const&&>));
+    }
+
+    {
+      using S1 = int();
+      using S2 = int(int);
+
+      auto& fref = f;
+
+      compat::function_ref<S1> fv1(fref);
+      BOOST_TEST_EQ(fv1(), -1);
+
+      compat::function_ref<S2> fv2(fref);
+      BOOST_TEST_EQ(fv2(1), 1);
+    }
+
+    {
+      using S1 = int();
+      using S2 = int(int);
+
+      compat::function_ref<S1> fv1(std::move(f));
+      BOOST_TEST_EQ(fv1(), -1);
+
+      compat::function_ref<S2> fv2(std::move(f));
+      BOOST_TEST_EQ(fv2(1), 1);
+    }
+
+    {
+      using S3 = int(int, int) const;
+      using S4 = int(int, int, int) const;
+
+      auto const& fref = f;
+
+      compat::function_ref<S3> fv3(fref);
+      BOOST_TEST_EQ(fv3(1, 2), 12);
+
+      compat::function_ref<S4> fv4(fref);
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+    }
+
+    {
+      using S3 = int(int, int) const;
+      using S4 = int(int, int, int) const;
+
+      auto const&& fref = std::move(f);
+
+      compat::function_ref<S3> fv3(fref);
+      BOOST_TEST_EQ(fv3(1, 2), 12);
+
+      compat::function_ref<S4> fv4(fref);
+      BOOST_TEST_EQ(fv4(1, 2, 3), 123);
+    }
+  }
+
+  {
+    F2 g;
+    {
+      compat::function_ref<int(int, int)> fv1(g);
+      BOOST_TEST_EQ(fv1(3, 2), 321);
+
+      auto& gref = g;
+      compat::function_ref<int(int, int)> rfv1(gref);
+      BOOST_TEST_EQ(rfv1(3, 2), 321);
+
+      compat::function_ref<int(int, int)> fv2(std::move(g));
+      BOOST_TEST_EQ(fv2(3, 2), 321);
+
+      compat::function_ref<int(int, int) const> fv3(g);
+      BOOST_TEST_EQ(fv3(3, 2), 322);
+
+      auto const& gcref = g;
+      compat::function_ref<int(int, int) const> crfv3(gcref);
+      BOOST_TEST_EQ(fv3(3, 2), 322);
+
+      compat::function_ref<int(int, int) const> fv4(std::move(g));
+      BOOST_TEST_EQ(fv4(3, 2), 322);
+    }
+  }
+
+  // invoke_r
+  {
+    F1 f;
+
+    compat::function_ref<X(int, int, int)> fv1(f);
+    BOOST_TEST_EQ(fv1(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int)>, F1>));
+    BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<Z(int, int, int)>, F1>));
+
+    compat::function_ref<X(int, int, int) const> fv2(f);
+    BOOST_TEST_EQ(fv2(1, 2, 3).v, 123);
+    BOOST_TEST_TRAIT_FALSE((std::is_constructible<compat::function_ref<Y(int, int, int) const>, F1>));
+    BOOST_TEST_TRAIT_TRUE((std::is_constructible<compat::function_ref<Z(int, int, int) const>, F1>));
+
+    compat::function_ref<void(int, int, int)> fv3(f);
+    fv3(1, 2, 3);
+
+    compat::function_ref<void(int, int, int) const> fv4(f);
+    fv4(1, 2, 3);
+  }
+
+  // copy construct, copy assign
+  {
+    F1 f;
+
+    auto id = [] { return 7331; };
+
+    compat::function_ref<int()> fv(f);
+    compat::function_ref<int()> fv2(fv);
+    BOOST_TEST_EQ(fv(), fv2());
+
+    fv2 = compat::function_ref<int()>(id);
+    BOOST_TEST_EQ(fv2(), 7331);
+
+    auto add = [](int x, int y) { return x + y; };
+    compat::function_ref<int(int, int) const> cfv(f);
+    compat::function_ref<int(int, int) const> cfv2(cfv);
+    BOOST_TEST_EQ(cfv(1, 2), cfv2(1, 2));
+
+    cfv2 = compat::function_ref<int(int, int) const>(add);
+    BOOST_TEST_EQ(cfv2(1, 2), 3);
+  }
+
+  return boost::report_errors();
+}

test/integer_sequence_test.cpp

@@ -0,0 +1,55 @@
+// Copyright 2015 Peter Dimov.
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/integer_sequence.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <type_traits>
+#include <cstddef>
+
+int main()
+{
+    using boost::compat::integer_sequence;
+    using boost::compat::make_integer_sequence;
+    using boost::compat::index_sequence;
+    using boost::compat::make_index_sequence;
+    using boost::compat::index_sequence_for;
+
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<int, 0>, integer_sequence<int>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<int, 1>, integer_sequence<int, 0>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<int, 2>, integer_sequence<int, 0, 1>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<int, 3>, integer_sequence<int, 0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<int, 4>, integer_sequence<int, 0, 1, 2, 3>);
+
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<char, 0>, integer_sequence<char>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<char, 1>, integer_sequence<char, 0>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<char, 2>, integer_sequence<char, 0, 1>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<char, 3>, integer_sequence<char, 0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<char, 4>, integer_sequence<char, 0, 1, 2, 3>);
+
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<std::size_t, 0>, integer_sequence<std::size_t>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<std::size_t, 1>, integer_sequence<std::size_t, 0>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<std::size_t, 2>, integer_sequence<std::size_t, 0, 1>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<std::size_t, 3>, integer_sequence<std::size_t, 0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(make_integer_sequence<std::size_t, 4>, integer_sequence<std::size_t, 0, 1, 2, 3>);
+
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<0>, integer_sequence<std::size_t>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<1>, integer_sequence<std::size_t, 0>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<2>, integer_sequence<std::size_t, 0, 1>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<3>, integer_sequence<std::size_t, 0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<4>, integer_sequence<std::size_t, 0, 1, 2, 3>);
+
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<0>, index_sequence<>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<1>, index_sequence<0>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<2>, index_sequence<0, 1>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<3>, index_sequence<0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(make_index_sequence<4>, index_sequence<0, 1, 2, 3>);
+
+    BOOST_TEST_TRAIT_SAME(index_sequence_for<>, index_sequence<>);
+    BOOST_TEST_TRAIT_SAME(index_sequence_for<void>, index_sequence<0>);
+    BOOST_TEST_TRAIT_SAME(index_sequence_for<void, void>, index_sequence<0, 1>);
+    BOOST_TEST_TRAIT_SAME(index_sequence_for<void, void, void>, index_sequence<0, 1, 2>);
+    BOOST_TEST_TRAIT_SAME(index_sequence_for<void, void, void, void>, index_sequence<0, 1, 2, 3>);
+
+    return boost::report_errors();
+}

test/invoke_fn_constexpr_test.cpp

@@ -0,0 +1,40 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+constexpr int f0()
+{
+    return -1;
+}
+
+constexpr int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+constexpr int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+constexpr int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::invoke( f0 ), -1 );
+    BOOST_TEST_EQ( boost::compat::invoke( f1, 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::invoke( f2, 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::invoke( f3, 1, 2, 3 ), 123 );
+}

test/invoke_fn_noexcept_test.cpp

@@ -0,0 +1,47 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped, __cpp_noexcept_function_type is not defined" )
+int main() {}
+
+#else
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke( f0 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke( f1, 1 ) ), true );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke( f2, 1, 2 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke( f3, 1, 2, 3 ) ), true );
+
+    return boost::report_errors();
+}
+
+#endif

test/invoke_fn_test.cpp

@@ -0,0 +1,40 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::invoke( f0 ), -1 );
+    BOOST_TEST_EQ( boost::compat::invoke( f1, 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::invoke( f2, 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::invoke( f3, 1, 2, 3 ), 123 );
+
+    return boost::report_errors();
+}

test/invoke_md_constexpr_test.cpp

@@ -0,0 +1,42 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, X() ), -1 );
+
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &x ), -1 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, >= 1920 && BOOST_MSVC < 1950)
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, Y() ), -1 );
+
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &y ), -1 );
+    }
+#endif
+}

test/invoke_md_noexcept_test.cpp

@@ -0,0 +1,60 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, X() ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, Y() ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::ref(x) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::cref(x) ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::ref(y) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::cref(y) ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::ref(x) ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::m, std::ref(y) ) ), true );
+    }
+
+    return boost::report_errors();
+}

test/invoke_md_test.cpp

@@ -0,0 +1,105 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, X() ), -1 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, Y() ), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, x ), -1 );
+        boost::compat::invoke( &X::m, x ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, x ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &x ), -1 );
+        boost::compat::invoke( &X::m, &x ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &x ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(x) ), -1 );
+        boost::compat::invoke( &X::m, std::ref(x) ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(x) ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::cref(x) ), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, y ), -1 );
+        boost::compat::invoke( &X::m, y ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, y ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &y ), -1 );
+        boost::compat::invoke( &X::m, &y ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &y ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(y) ), -1 );
+        boost::compat::invoke( &X::m, std::ref(y) ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(y) ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::cref(y) ), -1 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(x) ), -1 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::m, std::ref(y) ), -1 );
+    }
+
+    return boost::report_errors();
+}

test/invoke_mfn_constexpr_test.cpp

@@ -0,0 +1,88 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    constexpr int f0() const
+    {
+        return -1;
+    }
+
+    constexpr int f1( int x1 ) const noexcept
+    {
+        return x1;
+    }
+
+    constexpr int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, X(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, Y(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &x, 1, 2, 3 ), 123 );
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+    {
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, &y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &y, 1, 2, 3 ), 123 );
+    }
+#endif
+}

test/invoke_mfn_noexcept_test.cpp

@@ -0,0 +1,134 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped, __cpp_noexcept_function_type is not defined" )
+int main() {}
+
+#else
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, X() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, X(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, X(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, X(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, Y() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, Y(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, Y(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, Y(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, &x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, &x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, std::ref(x) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, std::ref(x), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::cref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::cref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, &y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, &y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f0, std::ref(y) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f1, std::ref(y), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::cref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::cref(y), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+    }
+
+    return boost::report_errors();
+}
+
+#endif

test/invoke_mfn_test.cpp

@@ -0,0 +1,127 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, X(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, Y(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::cref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, &y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f0, std::ref(y) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f1, std::ref(y), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::ref(y), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::cref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::cref(y), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::ref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f2, std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( &X::f3, std::ref(y), 1, 2, 3 ), 123 );
+    }
+
+    return boost::report_errors();
+}

test/invoke_obj_constexpr_test.cpp

@@ -0,0 +1,50 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+
+#define STATIC_ASSERT(...) static_assert(__VA_ARGS__, #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct F
+{
+    constexpr int operator()() const
+    {
+        return -1;
+    }
+
+    constexpr int operator()( int x1 ) const noexcept
+    {
+        return x1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( F() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        constexpr F f = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( f ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2, 3 ), 123 );
+    }
+}

test/invoke_obj_noexcept_test.cpp

@@ -0,0 +1,57 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct F
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( F() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( F(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( F(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( F(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        F f = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f, 1, 2, 3 ) ), true );
+    }
+
+    {
+        F const f = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke( f, 1, 2, 3 ) ), true );
+    }
+
+    return boost::report_errors();
+}

test/invoke_obj_test.cpp

@@ -0,0 +1,57 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct F
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke( F() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( F(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        F f;
+
+        BOOST_TEST_EQ( boost::compat::invoke( f ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2, 3 ), 123 );
+    }
+
+    {
+        F const f = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke( f, 1, 2, 3 ), 123 );
+    }
+
+    return boost::report_errors();
+}

test/invoke_r_fn_constexpr_test.cpp

@@ -0,0 +1,50 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/config.hpp>
+
+#define STATIC_ASSERT(...) static_assert((__VA_ARGS__), #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+constexpr int f0()
+{
+    return -1;
+}
+
+constexpr int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+constexpr int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+constexpr int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f0 ), -1 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f1, 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f2, 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f3, 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+    STATIC_ASSERT( boost::compat::invoke_r<void>( f0 ), true );
+    STATIC_ASSERT( boost::compat::invoke_r<void>( f1, 1 ), true );
+    STATIC_ASSERT( boost::compat::invoke_r<void>( f2, 1, 2 ), true );
+    STATIC_ASSERT( boost::compat::invoke_r<void>( f3, 1, 2, 3 ), true );
+
+#endif
+}

test/invoke_r_fn_noexcept_test.cpp

@@ -0,0 +1,52 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped, __cpp_noexcept_function_type is not defined" )
+int main() {}
+
+#else
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f0 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f1, 1 ) ), true );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f2, 1, 2 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f3, 1, 2, 3 ) ), true );
+
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f0 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f1, 1 ) ), true );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f2, 1, 2 ) ), false );
+    BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f3, 1, 2, 3 ) ), true );
+
+    return boost::report_errors();
+}
+
+#endif

test/invoke_r_fn_test.cpp

@@ -0,0 +1,45 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+int f0()
+{
+    return -1;
+}
+
+int f1( int x1 ) noexcept
+{
+    return x1;
+}
+
+int f2( int x1, int x2 )
+{
+    return 10*x1+x2;
+}
+
+int f3( int x1, int x2, int x3 ) noexcept
+{
+    return 100*x1 + 10*x2 + x3;
+}
+
+int main()
+{
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f0 ), -1 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f1, 1 ), 1 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f2, 1, 2 ), 12 );
+    BOOST_TEST_EQ( boost::compat::invoke_r<long>( f3, 1, 2, 3 ), 123 );
+
+    boost::compat::invoke_r<void>( f0 );
+    boost::compat::invoke_r<void>( f1, 1 );
+    boost::compat::invoke_r<void>( f2, 1, 2 );
+    boost::compat::invoke_r<void>( f3, 1, 2, 3 );
+
+    return boost::report_errors();
+}

test/invoke_r_md_constexpr_test.cpp

@@ -0,0 +1,56 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#define STATIC_ASSERT(...) static_assert((__VA_ARGS__), #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &x ), -1 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, X() ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, x ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, &x ), true );
+
+#endif
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, >= 1920 && BOOST_MSVC < 1950)
+    {
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &y ), -1 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, Y() ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, y ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::m, &y ), true );
+
+#endif
+    }
+#endif
+}

test/invoke_r_md_noexcept_test.cpp

@@ -0,0 +1,99 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, X() ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, Y() ) ), true );
+    }
+
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, X() ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, Y() ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::ref(x) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::cref(x) ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::ref(x) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::cref(x) ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::ref(y) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::cref(y) ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::ref(y) ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::cref(y) ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::ref(x) ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, &x ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::ref(x) ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::m, std::ref(y) ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, &y ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::m, std::ref(y) ) ), true );
+    }
+
+    return boost::report_errors();
+}

test/invoke_r_md_test.cpp

@@ -0,0 +1,131 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, X() ), -1 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, Y() ), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, x ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, x ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, x ), +1 );
+        boost::compat::invoke_r<void>( &X::m, x );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, &x ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, &x ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &x ), +1 );
+        boost::compat::invoke_r<void>( &X::m, &x );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::ref(x) ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, std::ref(x) ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::ref(x) ), +1 );
+        boost::compat::invoke_r<void>( &X::m, std::ref(x) );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::cref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::cref(x) ), -1 );
+        boost::compat::invoke_r<void>( &X::m, std::cref(x) );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, y ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, y ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, y ), +1 );
+        boost::compat::invoke_r<void>( &X::m, y );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, &y ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, &y ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &y ), +1 );
+        boost::compat::invoke_r<void>( &X::m, &y );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::ref(y) ), -1 );
+        boost::compat::invoke_r<int&>( &X::m, std::ref(y) ) = +1;
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::ref(y) ), +1 );
+        boost::compat::invoke_r<void>( &X::m, std::ref(y) );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::cref(y) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::cref(y) ), -1 );
+        boost::compat::invoke_r<void>( &X::m, std::cref(y) );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, x ), -1 );
+        boost::compat::invoke_r<void>( &X::m, x );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &x ), -1 );
+        boost::compat::invoke_r<void>( &X::m, &x );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::ref(x) ), -1 );
+        boost::compat::invoke_r<void>( &X::m, std::ref(x) );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, y ), -1 );
+        boost::compat::invoke_r<void>( &X::m, y );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, &y ), -1 );
+        boost::compat::invoke_r<void>( &X::m, &y );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<int const&>( &X::m, std::ref(y) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::m, std::ref(y) ), -1 );
+        boost::compat::invoke_r<void>( &X::m, std::ref(y) );
+    }
+
+    return boost::report_errors();
+}

test/invoke_r_mfn_constexpr_test.cpp

@@ -0,0 +1,134 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+#define STATIC_ASSERT(...) static_assert((__VA_ARGS__), #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct X
+{
+    constexpr int f0() const
+    {
+        return -1;
+    }
+
+    constexpr int f1( int x1 ) const noexcept
+    {
+        return x1;
+    }
+
+    constexpr int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, X(), 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, X() ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, X(), 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, X(), 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, X(), 1, 2, 3 ), true );
+
+#endif
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, Y(), 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, Y() ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, Y(), 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, Y(), 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, Y(), 1, 2, 3 ), true );
+
+#endif
+    }
+
+    {
+        constexpr X x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &x, 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, x ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, x, 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, x, 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, x, 1, 2, 3 ), true );
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, &x ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, &x, 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, &x, 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, &x, 1, 2, 3 ), true );
+
+#endif
+    }
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+    {
+        constexpr Y y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, &y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, y ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, y, 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, y, 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, y, 1, 2, 3 ), true );
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f0, &y ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f1, &y, 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f2, &y, 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( &X::f3, &y, 1, 2, 3 ), true );
+
+#endif
+    }
+#endif
+}

test/invoke_r_mfn_noexcept_test.cpp

@@ -0,0 +1,214 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/config/pragma_message.hpp>
+
+#if !defined(__cpp_noexcept_function_type)
+
+BOOST_PRAGMA_MESSAGE( "Test skipped, __cpp_noexcept_function_type is not defined" )
+int main() {}
+
+#else
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, X() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, X(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, X(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, X(), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, X() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, X(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, X(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, X(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, Y() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, Y(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, Y(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, Y(), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, Y() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, Y(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, Y(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, Y(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, &x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, &x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, std::ref(x) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, std::ref(x), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::cref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::cref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, &x ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, &x, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, std::ref(x) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, std::ref(x), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::cref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::cref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, &y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, &y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f0, std::ref(y) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f1, std::ref(y), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::cref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::cref(y), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, &y ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, &y, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f0, std::ref(y) ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f1, std::ref(y), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::cref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::cref(y), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, &x, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, &x, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::ref(x), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::ref(x), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, &y, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, &y, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f2, std::ref(y), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( &X::f3, std::ref(y), 1, 2, 3 ) ), true );
+    }
+
+    return boost::report_errors();
+}
+
+#endif

test/invoke_r_mfn_test.cpp

@@ -0,0 +1,211 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, X(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, Y(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::cref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, &y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f0, std::ref(y) ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f1, std::ref(y), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::ref(y), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::cref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::cref(y), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::ref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f2, std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( &X::f3, std::ref(y), 1, 2, 3 ), 123 );
+    }
+
+    {
+        boost::compat::invoke_r<void>( &X::f0, X() );
+        boost::compat::invoke_r<void>( &X::f1, X(), 1 );
+        boost::compat::invoke_r<void>( &X::f2, X(), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, X(), 1, 2, 3 );
+    }
+
+    {
+        boost::compat::invoke_r<void>( &X::f0, Y() );
+        boost::compat::invoke_r<void>( &X::f1, Y(), 1 );
+        boost::compat::invoke_r<void>( &X::f2, Y(), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, Y(), 1, 2, 3 );
+    }
+
+    {
+        X x;
+
+        boost::compat::invoke_r<void>( &X::f0, x );
+        boost::compat::invoke_r<void>( &X::f1, x, 1 );
+        boost::compat::invoke_r<void>( &X::f2, x, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, x, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f0, &x );
+        boost::compat::invoke_r<void>( &X::f1, &x, 1 );
+        boost::compat::invoke_r<void>( &X::f2, &x, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, &x, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f0, std::ref(x) );
+        boost::compat::invoke_r<void>( &X::f1, std::ref(x), 1 );
+        boost::compat::invoke_r<void>( &X::f2, std::ref(x), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, std::ref(x), 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f2, std::cref(x), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, std::cref(x), 1, 2, 3 );
+    }
+
+    {
+        Y y;
+
+        boost::compat::invoke_r<void>( &X::f0, y );
+        boost::compat::invoke_r<void>( &X::f1, y, 1 );
+        boost::compat::invoke_r<void>( &X::f2, y, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, y, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f0, &y );
+        boost::compat::invoke_r<void>( &X::f1, &y, 1 );
+        boost::compat::invoke_r<void>( &X::f2, &y, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, &y, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f0, std::ref(y) );
+        boost::compat::invoke_r<void>( &X::f1, std::ref(y), 1 );
+        boost::compat::invoke_r<void>( &X::f2, std::ref(y), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, std::ref(y), 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f2, std::cref(y), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, std::cref(y), 1, 2, 3 );
+    }
+
+    {
+        X const x = {};
+
+        boost::compat::invoke_r<void>( &X::f2, x, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, x, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f2, &x, 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, &x, 1, 2, 3 );
+
+        boost::compat::invoke_r<void>( &X::f2, std::ref(x), 1, 2 );
+        boost::compat::invoke_r<void>( &X::f3, std::ref(x), 1, 2, 3 );
+    }
+
+    {
+        Y const y = {};
+
+        boost::compat::invoke_r<long>( &X::f2, y, 1, 2 );
+        boost::compat::invoke_r<long>( &X::f3, y, 1, 2, 3 );
+
+        boost::compat::invoke_r<long>( &X::f2, &y, 1, 2 );
+        boost::compat::invoke_r<long>( &X::f3, &y, 1, 2, 3 );
+
+        boost::compat::invoke_r<long>( &X::f2, std::ref(y), 1, 2 );
+        boost::compat::invoke_r<long>( &X::f3, std::ref(y), 1, 2, 3 );
+    }
+
+    return boost::report_errors();
+}

test/invoke_r_obj_constexpr_test.cpp

@@ -0,0 +1,68 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+
+#define STATIC_ASSERT(...) static_assert((__VA_ARGS__), #__VA_ARGS__)
+#define BOOST_TEST_EQ(x, y) STATIC_ASSERT((x) == (y))
+
+struct F
+{
+    constexpr int operator()() const
+    {
+        return -1;
+    }
+
+    constexpr int operator()( int x1 ) const noexcept
+    {
+        return x1;
+    }
+
+    constexpr int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    constexpr int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( F() ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( F(), 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( F(), 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( F(), 1, 2, 3 ), true );
+
+#endif
+    }
+
+    {
+        constexpr F f = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2, 3 ), 123 );
+
+#if !defined(BOOST_NO_CXX14_CONSTEXPR)
+
+        STATIC_ASSERT( boost::compat::invoke_r<void>( f ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( f, 1 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( f, 1, 2 ), true );
+        STATIC_ASSERT( boost::compat::invoke_r<void>( f, 1, 2, 3 ), true );
+
+#endif
+    }
+}

test/invoke_r_obj_noexcept_test.cpp

@@ -0,0 +1,70 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct F
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( F() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( F(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( F(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( F(), 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( F() ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( F(), 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( F(), 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( F(), 1, 2, 3 ) ), true );
+    }
+
+    {
+        F f = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f, 1 ) ), true );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f, 1, 2, 3 ) ), true );
+    }
+
+    {
+        F const f = {};
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<long>( f, 1, 2, 3 ) ), true );
+
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f, 1, 2 ) ), false );
+        BOOST_TEST_EQ( noexcept( boost::compat::invoke_r<void>( f, 1, 2, 3 ) ), true );
+    }
+
+    return boost::report_errors();
+}

test/invoke_r_obj_test.cpp

@@ -0,0 +1,80 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test.hpp>
+
+struct F
+{
+    int operator()()
+    {
+        return -1;
+    }
+
+    int operator()( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int operator()( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F() ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( F(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        F f;
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f ), -1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2, 3 ), 123 );
+    }
+
+    {
+        F const f = {};
+
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::invoke_r<long>( f, 1, 2, 3 ), 123 );
+    }
+
+    {
+        boost::compat::invoke_r<void>( F() );
+        boost::compat::invoke_r<void>( F(), 1 );
+        boost::compat::invoke_r<void>( F(), 1, 2 );
+        boost::compat::invoke_r<void>( F(), 1, 2, 3 );
+    }
+
+    {
+        F f;
+
+        boost::compat::invoke_r<void>( f );
+        boost::compat::invoke_r<void>( f, 1 );
+        boost::compat::invoke_r<void>( f, 1, 2 );
+        boost::compat::invoke_r<void>( f, 1, 2, 3 );
+    }
+
+    {
+        F const f = {};
+
+        boost::compat::invoke_r<void>( f, 1, 2 );
+        boost::compat::invoke_r<void>( f, 1, 2, 3 );
+    }
+
+    return boost::report_errors();
+}

test/invoke_result_test.cpp

@@ -0,0 +1,107 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/mp11/utility.hpp>
+
+struct F
+{
+    void operator()()
+    {
+    }
+
+    char operator()( char x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    double operator()( float x1, float x2, float x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct X
+{
+};
+
+int main()
+{
+    using boost::compat::invoke_result_t;
+    using boost::mp11::mp_valid;
+
+    // nonfunction
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int, int, int> ));
+
+    // function reference
+
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<void(&)()>, void );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<char(&)(int), char>, char );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int(&)(int, int), int, int>, int );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<double(&)(double, double, double), float, float, float>, double );
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(&)(int), int, int> ));
+
+    // function pointer
+
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<void(*)()>, void );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<char(*)(int), char>, char );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int(*)(int, int), int, int>, int );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<double(*)(double, double, double), float, float, float>, double );
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(*)(int), int, int> ));
+
+    // object
+
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<F>, void );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<F, char>, char );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<F, int, int>, int );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<F, float, float, float>, double );
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, F const> ));
+
+    // member function pointer
+
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<void(X::*)(), X>, void );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<char(X::*)(int), X, char>, char );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int(X::*)(int, int), X, int, int>, int );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<double(X::*)(double, double, double), X, float, float, float>, double );
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, char(X::*)(int), X, int, int> ));
+
+    // member data pointer
+
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X>, int&& );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X const>, int const&& );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X&>, int& );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X const&>, int const& );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X*>, int& );
+    BOOST_TEST_TRAIT_SAME( invoke_result_t<int X::*, X const*>, int const& );
+
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( mp_valid<invoke_result_t, int X::*, X, int> ));
+
+    return boost::report_errors();
+}

test/is_invocable_r_test.cpp

@@ -0,0 +1,195 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct F
+{
+    void operator()()
+    {
+    }
+
+    char operator()( char x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    double operator()( float x1, float x2, float x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct X
+{
+};
+
+int main()
+{
+    using boost::compat::is_invocable_r;
+
+    // nonfunction
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int, int, int> ));
+
+    // function reference
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(&)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, char(&)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, double(&)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, void(&)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, char(&)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, double(&)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, void(&)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, char(&)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, double(&)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(&)(int), int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(&)(int), int, int> ));
+
+    // function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(*)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, char(*)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, double(*)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, void(*)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, char(*)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, double(*)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, void(*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, char(*)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, double(*)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(*)(int), int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(*)(int), int, int> ));
+
+    // object
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, F> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, F, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, F> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, F, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, F, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, F, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, F const> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, F const> ));
+
+    // member function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, double(X::*)(double, double, double), X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, double(X::*)(double, double, double), X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, double(X::*)(double, double, double), X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, char(X::*)(int), X, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, char(X::*)(int), X, int, int> ));
+
+    // member data pointer
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<long, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<void, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X const> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<X, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<int&, int X::*, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<int&, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<int&, int X::*, X&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<int&, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<int&, int X::*, X*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<int&, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable_r<int&&, int X::*, X> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<long, int X::*, X, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable_r<void, int X::*, X, int> ));
+
+    return boost::report_errors();
+}

test/is_invocable_test.cpp

@@ -0,0 +1,105 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+
+struct F
+{
+    void operator()()
+    {
+    }
+
+    char operator()( char x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    double operator()( float x1, float x2, float x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct X
+{
+};
+
+int main()
+{
+    using boost::compat::is_invocable;
+
+    // nonfunction
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int, int, int> ));
+
+    // function reference
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<void(&)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<char(&)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<double(&)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(&)(int), int, int> ));
+
+    // function pointer
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<void(*)()> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<char(*)(int), char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<double(*)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(*)(int), int, int> ));
+
+    // object
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<F> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<F, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<F const> ));
+
+    // member function pointer
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<double(X::*)(double, double, double), X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<char(X::*)(int), X, int, int> ));
+
+    // member data pointer
+
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_invocable<int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_invocable<int X::*, X, int> ));
+
+    return boost::report_errors();
+}

test/is_nothrow_invocable_r_test.cpp

@@ -0,0 +1,288 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+struct F
+{
+    void operator()()
+    {
+    }
+
+    char operator()( char x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    double operator()( float x1, float x2, float x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct X
+{
+};
+
+struct Y
+{
+    Y( int );
+    Y( double ) noexcept;
+};
+
+int main()
+{
+    using boost::compat::is_nothrow_invocable_r;
+
+    // nonfunction
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int, int, int> ));
+
+    // function reference
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(&)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(&)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, double(&)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(&)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(&)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, double(&)(double, double, double), float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(&)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, char(&)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int(&)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, double(&)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, void(&)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, char(&)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int(&)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, double(&)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, void(&)() noexcept> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, char(&)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int(&)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, double(&)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, void(&)() noexcept> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, char(&)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int(&)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double(&)(double, double, double) noexcept, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(&)(int), int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(&)(int), int, int> ));
+
+    // function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(*)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, double(*)(double, double, double), float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(*)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, double(*)(double, double, double), float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(*)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, char(*)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int(*)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, double(*)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, void(*)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, char(*)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int(*)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, double(*)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, void(*)() noexcept> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, char(*)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int(*)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, double(*)(double, double, double) noexcept, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, void(*)() noexcept> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, char(*)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int(*)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double(*)(double, double, double) noexcept, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(*)(int), int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(*)(int), int, int> ));
+
+    // object
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, F, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, F, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, F, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, F, int, int> ));
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, F, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, F, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, F, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, F const> ));
+
+    // member function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, double(X::*)(double, double, double), X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, double(X::*)(double, double, double), X, float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(X::*)() noexcept, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, char(X::*)(int) noexcept, X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int(X::*)(int, int) noexcept, X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, double(X::*)(double, double, double) noexcept, X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, void(X::*)() noexcept, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, char(X::*)(int) noexcept, X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int(X::*)(int, int) noexcept, X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, double(X::*)(double, double, double) noexcept, X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, void(X::*)() noexcept, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, char(X::*)(int) noexcept, X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int(X::*)(int, int) noexcept, X, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, double(X::*)(double, double, double) noexcept, X, float, float, float> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, void(X::*)() noexcept, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, char(X::*)(int) noexcept, X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int(X::*)(int, int) noexcept, X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double(X::*)(double, double, double) noexcept, X, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, char(X::*)(int), X, int, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, char(X::*)(int), X, int, int> ));
+
+    // member data pointer
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<long, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<void, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X const> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<X, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X const> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<Y, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<Y, double X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<int&, int X::*, X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<int&, int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<int&, int X::*, X&> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<int&, int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<int&, int X::*, X*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<int&, int X::*, X const*> ));
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable_r<int&&, int X::*, X> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<long, int X::*, X, int> ));
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable_r<void, int X::*, X, int> ));
+
+    return boost::report_errors();
+}

test/is_nothrow_invocable_test.cpp

@@ -0,0 +1,143 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/invoke.hpp>
+#include <boost/core/lightweight_test_trait.hpp>
+#include <boost/config.hpp>
+#include <boost/config/workaround.hpp>
+
+struct F
+{
+    void operator()()
+    {
+    }
+
+    char operator()( char x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int operator()( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    double operator()( float x1, float x2, float x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct X
+{
+};
+
+int main()
+{
+    using boost::compat::is_nothrow_invocable;
+
+    // nonfunction
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int, int, int> ));
+
+    // function reference
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(&)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(&)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int(&)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<double(&)(double, double, double), float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<void(&)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<char(&)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int(&)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<double(&)(double, double, double) noexcept, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(&)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(&)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(&)(int), int, int> ));
+
+    // function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(*)(int), char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int(*)(int, int), int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<double(*)(double, double, double), float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<void(*)() noexcept> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<char(*)(int) noexcept, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int(*)(int, int) noexcept, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<double(*)(double, double, double) noexcept, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(*)(int), int, int> ));
+
+    // object
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<F> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<F, int, int> ));
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<F, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<F, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<F, int, int, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<F const> ));
+
+    // member function pointer
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(X::*)(), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(X::*)(int), X, char> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int(X::*)(int, int), X, int, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<double(X::*)(double, double, double), X, float, float, float> ));
+
+#if defined(__cpp_noexcept_function_type)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<void(X::*)() noexcept, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<char(X::*)(int) noexcept, X, char> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int(X::*)(int, int) noexcept, X, int, int> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<double(X::*)(double, double, double) noexcept, X, float, float, float> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(X::*)()> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(X::*)(), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<void(X::*)(), X, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(X::*)(int)> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(X::*)(int), int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(X::*)(int), X> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<char(X::*)(int), X, int, int> ));
+
+    // member data pointer
+
+#if !BOOST_WORKAROUND(BOOST_MSVC, < 1910)
+
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X const> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X const&> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X*> ));
+    BOOST_TEST_TRAIT_TRUE(( is_nothrow_invocable<int X::*, X const*> ));
+
+#endif
+
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int X::*> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int X::*, int> ));
+    BOOST_TEST_TRAIT_FALSE(( is_nothrow_invocable<int X::*, X, int> ));
+
+    return boost::report_errors();
+}

test/mem_fn_md_test.cpp

@@ -0,0 +1,105 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#include <boost/compat/mem_fn.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int m = -1;
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( X() ), -1 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( Y() ), -1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( x ), -1 );
+        boost::compat::mem_fn( &X::m )( x ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( x ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &x ), -1 );
+        boost::compat::mem_fn( &X::m )( &x ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &x ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(x) ), -1 );
+        boost::compat::mem_fn( &X::m )( std::ref(x) ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(x) ), +1 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::cref(x) ), -1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( y ), -1 );
+        boost::compat::mem_fn( &X::m )( y ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( y ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &y ), -1 );
+        boost::compat::mem_fn( &X::m )( &y ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &y ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(y) ), -1 );
+        boost::compat::mem_fn( &X::m )( std::ref(y) ) = +1;
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(y) ), +1 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::cref(y) ), -1 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( x ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(x) ), -1 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( y ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::m )( std::ref(y) ), -1 );
+    }
+
+    return boost::report_errors();
+}

test/mem_fn_mfn_test.cpp

@@ -0,0 +1,127 @@
+// Copyright 2024 Peter Dimov
+// Distributed under the Boost Software License, Version 1.0.
+// https://www.boost.org/LICENSE_1_0.txt
+
+#if defined(__GNUC__) && __GNUC__ == 7
+# pragma GCC diagnostic ignored "-Wnoexcept-type"
+#endif
+
+#include <boost/compat/mem_fn.hpp>
+#include <boost/core/lightweight_test.hpp>
+#include <functional>
+
+struct X
+{
+    int f0()
+    {
+        return -1;
+    }
+
+    int f1( int x1 ) noexcept
+    {
+        return x1;
+    }
+
+    int f2( int x1, int x2 ) const
+    {
+        return 10*x1+x2;
+    }
+
+    int f3( int x1, int x2, int x3 ) const noexcept
+    {
+        return 100*x1 + 10*x2 + x3;
+    }
+};
+
+struct Y: public virtual X
+{
+};
+
+int main()
+{
+    {
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( X() ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( X(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( X(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( X(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( Y() ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( Y(), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( Y(), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( Y(), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X x;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( x ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( &x ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( &x, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( std::ref(x) ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( std::ref(x), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::cref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::cref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y y;
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( y ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( &y ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( &y, 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f0 )( std::ref(y) ), -1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f1 )( std::ref(y), 1 ), 1 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::ref(y), 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::cref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::cref(y), 1, 2, 3 ), 123 );
+    }
+
+    {
+        X const x = {};
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( &x, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( &x, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::ref(x), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::ref(x), 1, 2, 3 ), 123 );
+    }
+
+    {
+        Y const y = {};
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( &y, 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( &y, 1, 2, 3 ), 123 );
+
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f2 )( std::ref(y), 1, 2 ), 12 );
+        BOOST_TEST_EQ( boost::compat::mem_fn( &X::f3 )( std::ref(y), 1, 2, 3 ), 123 );
+    }
+
+    return boost::report_errors();
+}

test/quick.cpp

@@ -4,6 +4,9 @@
 
 #include <boost/compat/latch.hpp>
 #include <boost/compat/shared_lock.hpp>
+#include <boost/compat/invoke.hpp>
+#include <boost/compat/bind_front.hpp>
+#include <boost/compat/bind_back.hpp>
 
 int main()
 {