From d179658a0816fe97646fc8026366c44e1c207624 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Wed, 5 Nov 2025 15:04:50 +0100
Subject: [PATCH] Add small test to set/flat_map for transparent erase

---
 include/boost/container/flat_set.hpp | 13 +++++++++++++
 test/flat_set_test.cpp               | 10 ++++++++++
 test/set_test.cpp                    | 10 ++++++++++
 3 files changed, 33 insertions(+)

diff --git a/include/boost/container/flat_set.hpp b/include/boost/container/flat_set.hpp
index 91d15e0..672f3a2 100644
--- a/include/boost/container/flat_set.hpp
+++ b/include/boost/container/flat_set.hpp
@@ -801,6 +801,15 @@ class flat_set
    //!   linear to the elements with bigger keys.
    iterator erase(const_iterator first, const_iterator last);
 
+   //! <b>Requires</b>: This overload is available only if
+   //! key_compare::is_transparent exists.
+   //!
+   //! <b>Effects</b>: If present, erases the element in the container with key equivalent to x.
+   //!
+   //! <b>Returns</b>: Returns the number of erased elements.
+   template<class K>
+   size_type erase(K && k);
+
    //! <b>Effects</b>: Swaps the contents of *this and x.
    //!
    //! <b>Throws</b>: Nothing.
@@ -1736,6 +1745,10 @@ class flat_multiset
    //! @copydoc ::boost::container::flat_set::erase(const_iterator,const_iterator)
    iterator erase(const_iterator first, const_iterator last);
 
+   //! @copydoc ::boost::container::flat_set::erase(K&&)
+   template<class K>
+   size_type erase(K && k);
+
    //! @copydoc ::boost::container::flat_set::swap
    void swap(flat_multiset& x)
       BOOST_NOEXCEPT_IF(  allocator_traits_type::is_always_equal::value
diff --git a/test/flat_set_test.cpp b/test/flat_set_test.cpp
index 36612c9..2aea2cb 100644
--- a/test/flat_set_test.cpp
+++ b/test/flat_set_test.cpp
@@ -580,6 +580,16 @@ bool test_heterogeneous_lookups()
    if(*cmset1.equal_range(find_me).second != 3)
       return false;
 
+   //erase
+   if (set1.erase(find_me) != 1)
+      return false;
+   if (set1.erase(find_me) != 0)
+      return false;
+   if (mset1.erase(find_me) != 2)
+      return false;
+   if (mset1.erase(find_me) != 0)
+      return false;
+
    return true;
 }
 
diff --git a/test/set_test.cpp b/test/set_test.cpp
index 35c1d0e..a7be5ae 100644
--- a/test/set_test.cpp
+++ b/test/set_test.cpp
@@ -437,6 +437,16 @@ bool test_heterogeneous_lookups()
    if(*cmset1.equal_range(find_me).second != 3)
       return false;
 
+   //erase
+   if (set1.erase(find_me) != 1)
+      return false;
+   if (set1.erase(find_me) != 0)
+      return false;
+   if (mset1.erase(find_me) != 2)
+      return false;
+   if (mset1.erase(find_me) != 0)
+      return false;
+
    return true;
 }