https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121707
Bug ID: 121707
Summary: Compiler spills std::string internals when used in
consteval context
Product: gcc
Version: 15.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: dascandy at gmail dot com
Target Milestone: ---
When compiling the below source code
#include <string>
template <typename = void>
struct T {
static constexpr std::string value{};
};
void f() {
T<>::value;
}
the compiler fails on the line in f() with the following error referring to the
members of the std::string being private:
<source>:5:34: error: 'std::__cxx11::basic_string<char>::<unnamed union>
std::__cxx11::basic_string<char>::<anonymous>' is private within this context
5 | static constexpr std::string value{};
| ^~~~~
In file included from
/cefs/b6/b615954805438726f22a60c9_converted_gcc-15.2.0/include/c++/15.2.0/string:56,
from <source>:1:
/cefs/b6/b615954805438726f22a60c9_converted_gcc-15.2.0/include/c++/15.2.0/bits/basic_string.h:220:7:
note: declared private here
220 | union
| ^~~~~
<source>:5:34: error: 'char std::__cxx11::basic_string<char>::<unnamed
union>::_M_local_buf [16]' is private within this context
5 | static constexpr std::string value{};
| ^~~~~
/cefs/b6/b615954805438726f22a60c9_converted_gcc-15.2.0/include/c++/15.2.0/bits/basic_string.h:222:26:
note: declared private here
222 | _CharT _M_local_buf[_S_local_capacity + 1];
| ^~~~~~~~~~~~
The same code works fine in Clang. Checked with `-std=c++26`.
https://godbolt.org/z/844x68798
