From: Jonathan Wakely <jwakely@redhat.com>
Date: Thu, 30 Jul 2020 19:58:09 +0000 (+0100)
Subject: libstdc++: Make COW string use allocator_traits for nested types
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=505297f57e1919a2a328a136f20181cc5b81a807;p=thirdparty%2Fgcc.git

libstdc++: Make COW string use allocator_traits for nested types

When compiled as C++20 the COW std::string fails due to assuming that
the allocator always defines size_type and difference_type. That has
been incorrect since C++11, but we got away with it for specializations
using std::allocator until those members were removed in C++20.

libstdc++-v3/ChangeLog:

	* include/bits/basic_string.h (size_type, difference_type):
	Use allocator_traits to obtain the allocator's size_type and
	difference_type.
---

diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index bc0c256b65e4..52cecdd7ca1e 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -3147,8 +3147,8 @@ _GLIBCXX_END_NAMESPACE_CXX11
       typedef _Traits					    traits_type;
       typedef typename _Traits::char_type		    value_type;
       typedef _Alloc					    allocator_type;
-      typedef typename _CharT_alloc_type::size_type	    size_type;
-      typedef typename _CharT_alloc_type::difference_type   difference_type;
+      typedef typename _CharT_alloc_traits::size_type	    size_type;
+      typedef typename _CharT_alloc_traits::difference_type difference_type;
 #if __cplusplus < 201103L
       typedef typename _CharT_alloc_type::reference	    reference;
       typedef typename _CharT_alloc_type::const_reference   const_reference;