From: Jonathan Wakely <jwakely@redhat.com>
Date: Tue, 4 Apr 2023 19:28:59 +0000 (+0100)
Subject: libstdc++: Define std::sub_match::swap member function (LWG 3204)
X-Git-Tag: releases/gcc-12.3.0~61
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=400f16556727b2ec8fe96dc13f44486683e4ecdf;p=thirdparty%2Fgcc.git

libstdc++: Define std::sub_match::swap member function (LWG 3204)

This was approved at the C++ meeting in February.

libstdc++-v3/ChangeLog:

	* include/bits/regex.h (sub_match::swap): New function.
	* testsuite/28_regex/sub_match/lwg3204.cc: New test.

(cherry picked from commit 44e17b8d8999a658af9f86681504d74a119a5f6f)
---

diff --git a/libstdc++-v3/include/bits/regex.h b/libstdc++-v3/include/bits/regex.h
index a94ef1900123..097ebf5a2663 100644
--- a/libstdc++-v3/include/bits/regex.h
+++ b/libstdc++-v3/include/bits/regex.h
@@ -980,6 +980,16 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
       { return this->_M_str().compare({__s, __n}); }
       /// @endcond
 
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 3204. sub_match::swap only swaps the base class
+      /// Swap the values of two sub_match objects.
+      void
+      swap(sub_match& __s) noexcept(__is_nothrow_swappable<_BiIter>::value)
+      {
+	this->pair<_BiIter, _BiIter>::swap(__s);
+	std::swap(matched, __s.matched);
+      }
+
     private:
       // Simplified basic_string_view for C++11
       struct __string_view
diff --git a/libstdc++-v3/testsuite/28_regex/sub_match/lwg3204.cc b/libstdc++-v3/testsuite/28_regex/sub_match/lwg3204.cc
new file mode 100644
index 000000000000..58ef0df58a14
--- /dev/null
+++ b/libstdc++-v3/testsuite/28_regex/sub_match/lwg3204.cc
@@ -0,0 +1,38 @@
+// { dg-do run { target c++11 } }
+#include <regex>
+#include <testsuite_hooks.h>
+
+// LWG 3204. sub_match::swap only swaps the base class
+
+int main()
+{
+  std::sub_match<const char*> a, b;
+  a.matched = true;
+  a.swap(b);
+  VERIFY( ! a.matched );
+  VERIFY( b.matched );
+}
+
+struct iter
+{
+  using value_type = char;
+  using difference_type = long;
+  using pointer = const char*;
+  using reference = const char&;
+  using iterator_category = std::bidirectional_iterator_tag;
+
+  iter();
+  iter(const iter&) noexcept(false);
+
+  iter& operator++();
+  iter operator++(int);
+  iter& operator--();
+  iter operator--(int);
+  reference operator*() const;
+  pointer operator->() const;
+};
+
+using CS = std::csub_match;
+static_assert( noexcept(std::declval<CS&>().swap(std::declval<CS&>())) );
+using IS = std::sub_match<iter>;
+static_assert( ! noexcept(std::declval<IS&>().swap(std::declval<IS&>())) );