https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115941
Bug ID: 115941
Summary: g++ compiler version 15 doesn't fails to build when
g++ 12 does (may be related to
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109247)
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: vincent.lebourlot at starqube dot com
Target Milestone: ---
Here is a minimal code that doesn't compile with gcc 15 trunk version
```
gcc-15/bin/g++ --version
g++ (GCC) 15.0.0 20240715 (experimental)
Copyright (C) 2024 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
```
```cpp
#include <vector>
#include <string_view>
#include <string>
#include <span>
class piece{
public:
std::string_view view;
piece(const void*)=delete;
template<size_t n>explicit piece(const
char(&s)[n])noexcept:view(s,n-1){}
};
class NLargeStringPiece{};
class string{
private:
std::array<unsigned char,16>value;
public:
string(const void*)=delete;
template<size_t n>string(const char(&s)[n])noexcept:value(){}
template<typename...Args>explicit string(const
Args&...args)requires(std::conjunction_v<std::disjunction<std::is_constructible<piece,Args>,std::is_constructible<NLargeStringPiece,Args>>...>):value(){}
};
int main() noexcept{
std::vector<std::pair<string,string>>foo{{{"foo","foo"}}};
std::vector<std::pair<string,string>>bar{{{"bar","bar"},{"bar","bar"}}};
return 0;
}
```
and the error being printed:
```
❯/usr/local/gcc/gcc-12.3/bin/g++
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp -o
/home/lebourlot/gcc15/StarQube/Sources/Scratch/Scratch.exe -std=c++2b -g -Wall
-fPIC -pie -static-libstdc++ -gdwarf-4 -pthread -maes -msse4.1 -isystem
/usr/local/include
❯/usr/local/gcc/gcc-15/bin/g++
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp -o
/home/lebourlot/gcc15/StarQube/Sources/Scratch/Scratch.exe -std=c++2b -g -Wall
-fPIC -pie -static-libstdc++ -gdwarf-4 -pthread -maes -msse4.1 -isystem
/usr/local/include
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp: In function
‘int main()’:
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp:27:87: error:
converting to ‘string’ from initializer list would use explicit constructor
‘string::string(const Args& ...) requires
conjunction_v<std::disjunction<std::is_constructible<piece, Args>,
std::is_constructible<NLargeStringPiece, Args> >...> [with Args = {char [4],
char [4]}]’
27 |
std::vector<std::pair<string,string>>bar{{{"bar","bar"},{"bar","bar"}}};
|
^
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp:21:51: note:
‘string::string(const Args& ...) requires
conjunction_v<std::disjunction<std::is_constructible<piece, Args>,
std::is_constructible<NLargeStringPiece, Args> >...> [with Args = {char [4],
char [4]}]’ declared here
21 | template<typename...Args>explicit string(const
Args&...args)requires(std::conjunction_v<std::disjunction<std::is_constructible<piece,Args>,std::is_constructible<NLargeStringPiece,Args>>...>):value(){}
| ^~~~~~
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp:27:87: error:
converting to ‘string’ from initializer list would use explicit constructor
‘string::string(const Args& ...) requires
conjunction_v<std::disjunction<std::is_constructible<piece, Args>,
std::is_constructible<NLargeStringPiece, Args> >...> [with Args = {char [4],
char [4]}]’
27 |
std::vector<std::pair<string,string>>bar{{{"bar","bar"},{"bar","bar"}}};
|
^
/home/lebourlot/gcc15/StarQube/Sources/Scratch/ToolScratch.cpp:21:51: note:
‘string::string(const Args& ...) requires
conjunction_v<std::disjunction<std::is_constructible<piece, Args>,
std::is_constructible<NLargeStringPiece, Args> >...> [with Args = {char [4],
char [4]}]’ declared here
21 | template<typename...Args>explicit string(const
Args&...args)requires(std::conjunction_v<std::disjunction<std::is_constructible<piece,Args>,std::is_constructible<NLargeStringPiece,Args>>...>):value(){}
| ^~~~~~
[1] 876699 exit 1 /usr/local/gcc/gcc-15/bin/g++ -o -std=c++2b -g -Wall
-fPIC -pie -gdwarf-4
```
