Implement LWG#2579: Inconsistency wrt Allocators in basic_string assignment vs. basic_string::assign

llvm-svn: 263042

2 files changed, 35 insertions, 11 deletions

diff --git a/libcxx/include/string b/libcxx/include/string
index 6f5089c17fa..b937d295b84 100644
--- a/libcxx/include/string
+++ b/libcxx/include/string
@@ -1551,7 +1551,7 @@ public:
     _LIBCPP_INLINE_VISIBILITY const_reference back() const;
 
     _LIBCPP_INLINE_VISIBILITY
-    basic_string& assign(const basic_string& __str);
+    basic_string& assign(const basic_string& __str) { return *this = __str; }
 #ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
     _LIBCPP_INLINE_VISIBILITY
     basic_string& assign(basic_string&& str)
@@ -2489,7 +2489,7 @@ basic_string<_CharT, _Traits, _Allocator>::operator=(const basic_string& __str)
     if (this != &__str)
     {
         __copy_assign_alloc(__str);
-        assign(__str);
+        assign(__str.data(), __str.size());
     }
     return *this;
 }
@@ -2581,14 +2581,6 @@ basic_string<_CharT, _Traits, _Allocator>::assign(_ForwardIterator __first, _For
 }
 
 template <class _CharT, class _Traits, class _Allocator>
-inline _LIBCPP_INLINE_VISIBILITY
-basic_string<_CharT, _Traits, _Allocator>&
-basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str)
-{
-    return assign(__str.data(), __str.size());
-}
-
-template <class _CharT, class _Traits, class _Allocator>
 basic_string<_CharT, _Traits, _Allocator>&
 basic_string<_CharT, _Traits, _Allocator>::assign(const basic_string& __str, size_type __pos, size_type __n)
 {
diff --git a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
index 2bc5dd223e6..04954334bc0 100644
--- a/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
+++ b/libcxx/test/std/strings/basic.string/string.modifiers/string_assign/string.pass.cpp
@@ -15,7 +15,9 @@
 #include <string>
 #include <cassert>
 
+#include "test_macros.h"
 #include "min_allocator.h"
+#include "test_allocator.h"
 
 template <class S>
 void
@@ -26,6 +28,16 @@ test(S s, S str, S expected)
     assert(s == expected);
 }
 
+template <class S>
+void
+testAlloc(S s, S str, const typename S::allocator_type& a)
+{
+    s.assign(str);
+    assert(s.__invariants());
+    assert(s == str);
+    assert(s.get_allocator() == a);
+}
+
 int main()
 {
     {
@@ -50,7 +62,22 @@ int main()
     test(S("12345678901234567890"), S("1234567890"), S("1234567890"));
     test(S("12345678901234567890"), S("12345678901234567890"),
          S("12345678901234567890"));
+
+    testAlloc(S(), S(), std::allocator<char>());
+    testAlloc(S(), S("12345"), std::allocator<char>());
+    testAlloc(S(), S("1234567890"), std::allocator<char>());
+    testAlloc(S(), S("12345678901234567890"), std::allocator<char>());
+    }
+
+    { //  LWG#5579 make sure assign takes the allocators where appropriate
+    typedef other_allocator<char> A;  // has POCCA --> true
+    typedef std::basic_string<char, std::char_traits<char>, A> S;
+    testAlloc(S(A(5)), S(A(3)), A(3));
+    testAlloc(S(A(5)), S("1"), A());
+    testAlloc(S(A(5)), S("1", A(7)), A(7));
+    testAlloc(S(A(5)), S("1234567890123456789012345678901234567890123456789012345678901234567890", A(7)), A(7));
     }
+
 #if TEST_STD_VER >= 11
     {
     typedef std::basic_string<char, std::char_traits<char>, min_allocator<char>> S;
@@ -74,9 +101,14 @@ int main()
     test(S("12345678901234567890"), S("1234567890"), S("1234567890"));
     test(S("12345678901234567890"), S("12345678901234567890"),
          S("12345678901234567890"));
+
+    testAlloc(S(), S(), min_allocator<char>());
+    testAlloc(S(), S("12345"), min_allocator<char>());
+    testAlloc(S(), S("1234567890"), min_allocator<char>());
+    testAlloc(S(), S("12345678901234567890"), min_allocator<char>());
     }
 #endif
-#if __cplusplus > 201402L
+#if TEST_STD_VER > 14
     {
     typedef std::string S;
     static_assert(noexcept(S().assign(S())), "");  // LWG#2063