A call to `basic_string::clear()` in the std::string move assignment
operator leads to a constexpr error from an access of inactive union
member `_M_local_buf` in the added test (`test_move()`). Changing
`__str._M_local_buf` to `__str._M_use_local_data()` in
`operator=(basic_string&& __str)` fixes this.
PR libstdc++/113294
libstdc++-v3/ChangeLog:
* include/bits/basic_string.h (basic_string::operator=): Use
_M_use_local_data() instead of _M_local_buf on the moved-from
string.
* testsuite/21_strings/basic_string/modifiers/constexpr.cc
(test_move): New test.
Signed-off-by: Paul Keir <paul.keir@uws.ac.uk>
Reviewed-by: Patrick Palka <ppalka@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
__str._M_capacity(__capacity);
}
else
- __str._M_data(__str._M_local_buf);
+ __str._M_data(__str._M_use_local_data());
}
else // Need to do a deep copy
assign(__str);
}
static_assert( test_erasure() );
+
+constexpr bool
+test_move()
+{
+ // PR libstdc++/113294
+ std::string s1;
+ std::string s2 = "1234567890123456"; // 16 chars: more than _S_local_capacity
+ s1 = std::move(s2);
+ VERIFY( s1 == "1234567890123456" );
+
+ return true;
+}
+
+static_assert( test_move() );