From 2eb9867ec55287efa7f1d850ae0f77c9b084e59d Mon Sep 17 00:00:00 2001
From: Louis Dionne <ldionne.2@gmail.com>
Date: Wed, 16 Jul 2014 17:12:19 -0400
Subject: [PATCH] Comparable: Check laws widely

---
 include/boost/hana/comparable/laws.hpp        | 21 ++++++----
 test/comparable/laws.cpp                      | 14 +++----
 test/ext/boost/mpl/list/comparable/laws.cpp   | 31 ++++++++++++++
 test/ext/boost/mpl/vector/comparable/laws.cpp | 31 ++++++++++++++
 .../std/integer_sequence/comparable/laws.cpp  | 41 +++++++++++++++++++
 .../{comparable.cpp => comparable/equal.cpp}  |  0
 test/integral/comparable/laws.cpp             | 31 ++++++++++++++
 test/list/typeclass/comparable/laws.cpp       | 38 +++++++++++++++++
 test/maybe/comparable.cpp                     | 27 ------------
 test/maybe/comparable/equal.cpp               | 23 +++++++++++
 test/maybe/comparable/laws.cpp                | 28 +++++++++++++
 test/pair/instance/comparable/laws.cpp        | 27 ++++++++++++
 test/range/comparable.cpp                     | 26 ------------
 test/range/comparable/equal.cpp               | 26 ++++++++++++
 test/range/comparable/laws.cpp                | 29 +++++++++++++
 test/type/comparable/equal.cpp                | 26 ++++++++++++
 .../{comparable.cpp => comparable/laws.cpp}   | 12 +++---
 test/type_list/comparable/laws.cpp            | 30 ++++++++++++++
 18 files changed, 387 insertions(+), 74 deletions(-)
 create mode 100644 test/ext/boost/mpl/list/comparable/laws.cpp
 create mode 100644 test/ext/boost/mpl/vector/comparable/laws.cpp
 create mode 100644 test/ext/std/integer_sequence/comparable/laws.cpp
 rename test/integral/{comparable.cpp => comparable/equal.cpp} (100%)
 create mode 100644 test/integral/comparable/laws.cpp
 create mode 100644 test/list/typeclass/comparable/laws.cpp
 delete mode 100644 test/maybe/comparable.cpp
 create mode 100644 test/maybe/comparable/equal.cpp
 create mode 100644 test/maybe/comparable/laws.cpp
 create mode 100644 test/pair/instance/comparable/laws.cpp
 delete mode 100644 test/range/comparable.cpp
 create mode 100644 test/range/comparable/equal.cpp
 create mode 100644 test/range/comparable/laws.cpp
 create mode 100644 test/type/comparable/equal.cpp
 rename test/type/{comparable.cpp => comparable/laws.cpp} (54%)
 create mode 100644 test/type_list/comparable/laws.cpp

diff --git a/include/boost/hana/comparable/laws.hpp b/include/boost/hana/comparable/laws.hpp
index 0f87f86c8..4ecae25dc 100644
--- a/include/boost/hana/comparable/laws.hpp
+++ b/include/boost/hana/comparable/laws.hpp
@@ -12,6 +12,7 @@ Distributed under the Boost Software License, Version 1.0.
 
 #include <boost/hana/comparable/comparable.hpp>
 
+#include <boost/hana/foldable/foldable.hpp>
 #include <boost/hana/logical/logical.hpp>
 
 
@@ -25,14 +26,20 @@ namespace boost { namespace hana {
     //!     if a == b && b == c then a == c // Transitivity
     //! @endcode
     struct Comparable::laws {
-        template <typename A, typename B, typename C>
-        static constexpr auto check(A a, B b, C c) {
+        template <typename ComparableObjects>
+        static constexpr auto check(ComparableObjects objs) {
             auto implies = [](auto p, auto q) { return or_(not_(p), q); };
-            return and_(
-                equal(a, a),
-                implies(equal(a, b), equal(b, a)),
-                implies(and_(equal(a, b), equal(b, c)), equal(a, c))
-            );
+            return all([=](auto a) {
+                return all([=](auto b) {
+                    return all([=](auto c) {
+                        return and_(
+                            equal(a, a),
+                            implies(equal(a, b), equal(b, a)),
+                            implies(and_(equal(a, b), equal(b, c)), equal(a, c))
+                        );
+                    }, objs);
+                }, objs);
+            }, objs);
         }
     };
 }} // end namespace boost::hana
diff --git a/test/comparable/laws.cpp b/test/comparable/laws.cpp
index d5fc6cb81..924ee0282 100644
--- a/test/comparable/laws.cpp
+++ b/test/comparable/laws.cpp
@@ -18,15 +18,11 @@ using namespace boost::hana;
 template <typename mcd>
 void test() {
     constexpr auto comparable = detail::minimal::comparable<mcd>;
-
-    BOOST_HANA_CONSTEXPR_LAMBDA auto xs = list(comparable(0), comparable(1), comparable(2));
-    for_each(xs, [=](auto a) {
-        for_each(xs, [=](auto b) {
-            for_each(xs, [=](auto c) {
-                BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(a, b, c));
-            });
-        });
-    });
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(comparable(0), comparable(1), comparable(2))
+        )
+    );
 }
 
 int main() {
diff --git a/test/ext/boost/mpl/list/comparable/laws.cpp b/test/ext/boost/mpl/list/comparable/laws.cpp
new file mode 100644
index 000000000..6145d6c25
--- /dev/null
+++ b/test/ext/boost/mpl/list/comparable/laws.cpp
@@ -0,0 +1,31 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/ext/boost/mpl/list.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+
+#include <boost/mpl/list.hpp>
+using namespace boost::hana;
+
+
+template <int i> struct x;
+
+template <int ...i>
+constexpr boost::mpl::list<x<i>...> mpl_list{};
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(
+                mpl_list<>, mpl_list<0>, mpl_list<0, 1>,
+                mpl_list<0, 1, 2>, mpl_list<1, 0, 2>
+            )
+        )
+    );
+}
diff --git a/test/ext/boost/mpl/vector/comparable/laws.cpp b/test/ext/boost/mpl/vector/comparable/laws.cpp
new file mode 100644
index 000000000..5414c879a
--- /dev/null
+++ b/test/ext/boost/mpl/vector/comparable/laws.cpp
@@ -0,0 +1,31 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/ext/boost/mpl/vector.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+
+#include <boost/mpl/vector.hpp>
+using namespace boost::hana;
+
+
+template <int i> struct x;
+
+template <int ...i>
+constexpr boost::mpl::vector<x<i>...> mpl_vector{};
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(
+                mpl_vector<>, mpl_vector<0>, mpl_vector<0, 1>,
+                mpl_vector<0, 1, 2>, mpl_vector<1, 0, 2>
+            )
+        )
+    );
+}
diff --git a/test/ext/std/integer_sequence/comparable/laws.cpp b/test/ext/std/integer_sequence/comparable/laws.cpp
new file mode 100644
index 000000000..29620e048
--- /dev/null
+++ b/test/ext/std/integer_sequence/comparable/laws.cpp
@@ -0,0 +1,41 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/ext/std/integer_sequence.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+
+#include <utility>
+using namespace boost::hana;
+
+
+template <typename T, typename U>
+void test() {
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(
+                std::integer_sequence<T>{},
+                std::integer_sequence<U>{},
+
+                std::integer_sequence<T, 0>{},
+                std::integer_sequence<U, 0>{},
+
+                std::integer_sequence<T, 0, 1>{},
+                std::integer_sequence<U, 0, 1>{},
+
+                std::integer_sequence<T, 1, 0, 2>{},
+                std::integer_sequence<U, 1, 0, 2>{}
+            )
+        )
+    );
+}
+
+int main() {
+    test<int, int>();
+    test<int, unsigned long long>();
+}
diff --git a/test/integral/comparable.cpp b/test/integral/comparable/equal.cpp
similarity index 100%
rename from test/integral/comparable.cpp
rename to test/integral/comparable/equal.cpp
diff --git a/test/integral/comparable/laws.cpp b/test/integral/comparable/laws.cpp
new file mode 100644
index 000000000..2a9cd071f
--- /dev/null
+++ b/test/integral/comparable/laws.cpp
@@ -0,0 +1,31 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/integral.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+using namespace boost::hana;
+
+
+template <typename T, typename U>
+void test() {
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(
+                integral<T, 0>, integral<U, 0>,
+                integral<T, 1>, integral<U, 1>,
+                integral<T, 2>, integral<U, 2>
+            )
+        )
+    );
+}
+
+int main() {
+    test<int, int>();
+    test<int, unsigned long long>();
+}
diff --git a/test/list/typeclass/comparable/laws.cpp b/test/list/typeclass/comparable/laws.cpp
new file mode 100644
index 000000000..8cb6fc4ac
--- /dev/null
+++ b/test/list/typeclass/comparable/laws.cpp
@@ -0,0 +1,38 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/list/mcd.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/constexpr.hpp>
+#include <boost/hana/detail/minimal/comparable.hpp>
+#include <boost/hana/detail/minimal/list.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+using namespace boost::hana;
+
+
+template <int i>
+constexpr auto x = detail::minimal::comparable<>(i);
+
+template <typename mcd>
+void test() {
+    BOOST_HANA_CONSTEXPR_LAMBDA auto list = detail::minimal::list<mcd>;
+
+    BOOST_HANA_STATIC_ASSERT(
+        Comparable::laws::check(
+            list(
+                list(),
+                list(x<0>),
+                list(x<0>, x<1>),
+                list(x<0>, x<1>, x<2>)
+            )
+        )
+    );
+}
+
+int main() {
+    test<List::mcd<void>>();
+}
diff --git a/test/maybe/comparable.cpp b/test/maybe/comparable.cpp
deleted file mode 100644
index 14008cefc..000000000
--- a/test/maybe/comparable.cpp
+++ /dev/null
@@ -1,27 +0,0 @@
-/*
-@copyright Louis Dionne 2014
-Distributed under the Boost Software License, Version 1.0.
-(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
- */
-
-#include <boost/hana/maybe.hpp>
-
-#include <boost/hana/detail/static_assert.hpp>
-#include <boost/hana/integral.hpp>
-using namespace boost::hana;
-
-
-int main() {
-    BOOST_HANA_STATIC_ASSERT(nothing == nothing);
-    BOOST_HANA_STATIC_ASSERT(nothing != just(int_<0>));
-    BOOST_HANA_STATIC_ASSERT(just(int_<0>) != nothing);
-
-    BOOST_HANA_STATIC_ASSERT(just(int_<0>) == just(int_<0>));
-    BOOST_HANA_STATIC_ASSERT(just(int_<0>) != just(int_<1>));
-
-
-    BOOST_HANA_STATIC_ASSERT(just(0) == just(int_<0>));
-    BOOST_HANA_STATIC_ASSERT(just(0) != just(int_<1>));
-    BOOST_HANA_STATIC_ASSERT(just(int_<0>) == just(0));
-    BOOST_HANA_STATIC_ASSERT(just(int_<1>) != just(0));
-}
diff --git a/test/maybe/comparable/equal.cpp b/test/maybe/comparable/equal.cpp
new file mode 100644
index 000000000..4102698e8
--- /dev/null
+++ b/test/maybe/comparable/equal.cpp
@@ -0,0 +1,23 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/maybe.hpp>
+
+#include <boost/hana/detail/minimal/comparable.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+using namespace boost::hana;
+
+
+template <int i>
+constexpr auto x = detail::minimal::comparable<>(i);
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT( equal(nothing, nothing));
+    BOOST_HANA_STATIC_ASSERT(!equal(nothing, just(x<0>)));
+    BOOST_HANA_STATIC_ASSERT(!equal(just(x<0>), nothing));
+    BOOST_HANA_STATIC_ASSERT( equal(just(x<0>), just(x<0>)));
+    BOOST_HANA_STATIC_ASSERT(!equal(just(x<0>), just(x<1>)));
+}
diff --git a/test/maybe/comparable/laws.cpp b/test/maybe/comparable/laws.cpp
new file mode 100644
index 000000000..d372cf9c7
--- /dev/null
+++ b/test/maybe/comparable/laws.cpp
@@ -0,0 +1,28 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/maybe.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/minimal/comparable.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+using namespace boost::hana;
+
+
+template <int i>
+constexpr auto x = detail::minimal::comparable<>(i);
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(
+        list(
+            nothing,
+            just(x<0>),
+            just(x<1>),
+            just(x<2>)
+        )
+    ));
+}
diff --git a/test/pair/instance/comparable/laws.cpp b/test/pair/instance/comparable/laws.cpp
new file mode 100644
index 000000000..b8737010b
--- /dev/null
+++ b/test/pair/instance/comparable/laws.cpp
@@ -0,0 +1,27 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/pair/instance.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/minimal/comparable.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+using namespace boost::hana;
+
+
+template <int i>
+constexpr auto x = detail::minimal::comparable<>(i);
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(
+        list(
+            pair(x<0>, x<1>),
+            pair(x<1>, x<0>),
+            pair(x<0>, x<0>)
+        )
+    ));
+}
diff --git a/test/range/comparable.cpp b/test/range/comparable.cpp
deleted file mode 100644
index f15e97e4e..000000000
--- a/test/range/comparable.cpp
+++ /dev/null
@@ -1,26 +0,0 @@
-/*
-@copyright Louis Dionne 2014
-Distributed under the Boost Software License, Version 1.0.
-(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
- */
-
-#include <boost/hana/range.hpp>
-
-#include <boost/hana/detail/static_assert.hpp>
-#include <boost/hana/integral.hpp>
-using namespace boost::hana;
-
-
-int main() {
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<0>) == range(int_<0>, int_<0>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<0>) != range(int_<0>, int_<1>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<1>) != range(int_<0>, int_<0>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<1>) == range(int_<0>, int_<1>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<2>) != range(int_<0>, int_<1>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<2>) == range(int_<0>, int_<2>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<0>, int_<0>) == range(int_<2>, int_<2>));
-
-    BOOST_HANA_STATIC_ASSERT(range(int_<2>, int_<4>) == range(int_<2>, int_<4>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<-4>, int_<-3>) == range(int_<-4>, int_<-3>));
-    BOOST_HANA_STATIC_ASSERT(range(int_<-4>, int_<2>) == range(int_<-4>, int_<2>));
-}
diff --git a/test/range/comparable/equal.cpp b/test/range/comparable/equal.cpp
new file mode 100644
index 000000000..37ca32fb9
--- /dev/null
+++ b/test/range/comparable/equal.cpp
@@ -0,0 +1,26 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/range.hpp>
+
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/integral.hpp>
+using namespace boost::hana;
+
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT( equal(range(int_<0>, int_<0>), range(int_<0>, int_<0>)));
+    BOOST_HANA_STATIC_ASSERT(!equal(range(int_<0>, int_<0>), range(int_<0>, int_<1>)));
+    BOOST_HANA_STATIC_ASSERT(!equal(range(int_<0>, int_<1>), range(int_<0>, int_<0>)));
+    BOOST_HANA_STATIC_ASSERT( equal(range(int_<0>, int_<1>), range(int_<0>, int_<1>)));
+    BOOST_HANA_STATIC_ASSERT(!equal(range(int_<0>, int_<2>), range(int_<0>, int_<1>)));
+    BOOST_HANA_STATIC_ASSERT( equal(range(int_<0>, int_<2>), range(int_<0>, int_<2>)));
+    BOOST_HANA_STATIC_ASSERT( equal(range(int_<0>, int_<0>), range(int_<2>, int_<2>)));
+
+    BOOST_HANA_STATIC_ASSERT(equal(range(int_<2>, int_<4>), range(int_<2>, int_<4>)));
+    BOOST_HANA_STATIC_ASSERT(equal(range(int_<-4>, int_<-3>), range(int_<-4>, int_<-3>)));
+    BOOST_HANA_STATIC_ASSERT(equal(range(int_<-4>, int_<2>), range(int_<-4>, int_<2>)));
+}
diff --git a/test/range/comparable/laws.cpp b/test/range/comparable/laws.cpp
new file mode 100644
index 000000000..2a872e0b0
--- /dev/null
+++ b/test/range/comparable/laws.cpp
@@ -0,0 +1,29 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/range.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/integral.hpp>
+#include <boost/hana/list/instance.hpp>
+using namespace boost::hana;
+
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(
+        list(
+            range(int_<0>, int_<0>),
+            range(int_<1>, int_<1>),
+
+            range(int_<0>, int_<1>),
+            range(long_<0>, long_<1>),
+            range(long_<0>, int_<1>),
+
+            range(int_<3>, int_<6>)
+        )
+    ));
+}
diff --git a/test/type/comparable/equal.cpp b/test/type/comparable/equal.cpp
new file mode 100644
index 000000000..cbf70b410
--- /dev/null
+++ b/test/type/comparable/equal.cpp
@@ -0,0 +1,26 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/type.hpp>
+
+#include <boost/hana/detail/static_assert.hpp>
+using namespace boost::hana;
+
+
+struct T; struct U;
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT( equal(type<T>, type<T>));
+    BOOST_HANA_STATIC_ASSERT(!equal(type<T>, type<U>));
+    BOOST_HANA_STATIC_ASSERT(!equal(type<void>, type<U>));
+    BOOST_HANA_STATIC_ASSERT(!equal(type<T>, type<void>));
+    BOOST_HANA_STATIC_ASSERT( equal(type<void>, type<void>));
+
+    BOOST_HANA_STATIC_ASSERT( equal(type<T&>, type<T&>));
+    BOOST_HANA_STATIC_ASSERT(!equal(type<T&>, type<T&&>));
+    BOOST_HANA_STATIC_ASSERT(!equal(type<T const>, type<T>));
+    BOOST_HANA_STATIC_ASSERT( equal(type<T const>, type<T const>));
+}
diff --git a/test/type/comparable.cpp b/test/type/comparable/laws.cpp
similarity index 54%
rename from test/type/comparable.cpp
rename to test/type/comparable/laws.cpp
index 350e950bf..fa31604f3 100644
--- a/test/type/comparable.cpp
+++ b/test/type/comparable/laws.cpp
@@ -6,14 +6,16 @@ Distributed under the Boost Software License, Version 1.0.
 
 #include <boost/hana/type.hpp>
 
+#include <boost/hana/comparable/laws.hpp>
 #include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
 using namespace boost::hana;
 
 
-int main() {
-    BOOST_HANA_STATIC_ASSERT(equal(type<void>, type<void>));
-    BOOST_HANA_STATIC_ASSERT(!not_equal(type<void>, type<void>));
+struct T; struct U;
 
-    BOOST_HANA_STATIC_ASSERT(!equal(type<void>, type<int>));
-    BOOST_HANA_STATIC_ASSERT(not_equal(type<void>, type<int>));
+int main() {
+    BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(
+        list(type<T>, type<U>, type<void>, type<int>, type<int&>)
+    ));
 }
diff --git a/test/type_list/comparable/laws.cpp b/test/type_list/comparable/laws.cpp
new file mode 100644
index 000000000..7a83fe34f
--- /dev/null
+++ b/test/type_list/comparable/laws.cpp
@@ -0,0 +1,30 @@
+/*
+@copyright Louis Dionne 2014
+Distributed under the Boost Software License, Version 1.0.
+(See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
+ */
+
+#include <boost/hana/type_list.hpp>
+
+#include <boost/hana/comparable/laws.hpp>
+#include <boost/hana/detail/static_assert.hpp>
+#include <boost/hana/list/instance.hpp>
+using namespace boost::hana;
+
+
+template <int i>
+struct x;
+
+template <int ...i>
+constexpr auto tlist = type_list<x<i>...>;
+
+int main() {
+    BOOST_HANA_STATIC_ASSERT(Comparable::laws::check(
+        list(
+            tlist<>,
+            tlist<0>,
+            tlist<0, 1>,
+            tlist<0, 1, 2>
+        )
+    ));
+}