[Bug c++/98770] New: [modules] including certain stdlib headers in the global module fragment of different modules causes conflicting global module declarations
pilarlatiesa at gmail dot com
gcc-bugzilla@gcc.gnu.org
Wed Jan 20 14:36:52 GMT 2021
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98770
Bug ID: 98770
Summary: [modules] including certain stdlib headers in the
global module fragment of different modules causes
conflicting global module declarations
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: pilarlatiesa at gmail dot com
Target Milestone: ---
$ /home/pililatiesa/GCC-11/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/home/pililatiesa/GCC-11/bin/g++
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-master/configure --prefix=($HOME)/GCC-11
--enable-languages=c++ --disable-bootstrap
Thread model: posix
Supported LTO compression algorithms: zlib
gcc version 11.0.0 20210115 (experimental) (GCC)
$ cat Tensor.ixx
module;
#include <cstddef>
#include <iostream>
export module VF.Tensor;
namespace VF
{
export
template<std::size_t d, std::size_t r1>
struct TTensor
{
private:
std::istream
inline &Read(std::istream &is)
{ return is; }
};
export
template<std::size_t d>
using TVector = TTensor<d, 1u>;
} // VF
$ cat Mesh.ixx
module;
#include <cstddef>
#include <type_traits>
export module VF.Mesh;
import VF.Tensor;
namespace VF
{
template <std::size_t d>
class TPoint final : public TVector<d> {};
}
$ /home/pililatiesa/GCC-11/bin/g++ -fmodules-ts -x c++ -std=c++20 -I../ -I./
Tensor.ixx Mesh.ixx -o foo
In file included from
/home/pililatiesa/GCC-11/include/c++/11.0.0/bits/move.h:57,
from
/home/pililatiesa/GCC-11/include/c++/11.0.0/bits/nested_exception.h:40,
from
/home/pililatiesa/GCC-11/include/c++/11.0.0/exception:148,
from /home/pililatiesa/GCC-11/include/c++/11.0.0/ios:39,
from /home/pililatiesa/GCC-11/include/c++/11.0.0/ostream:38,
from /home/pililatiesa/GCC-11/include/c++/11.0.0/iostream:39,
from Tensor.ixx:5,
of module VF.Tensor, imported at Mesh.ixx:9:
/home/pililatiesa/GCC-11/include/c++/11.0.0/type_traits:634:31: error:
conflicting global module declaration ‘template<class ...> using __void_t =
void’
634 | template<typename...> using __void_t = void;
| ^~~~~~~~
In file included from Mesh.ixx:5:
/home/pililatiesa/GCC-11/include/c++/11.0.0/type_traits:634:31: note: existing
declaration ‘template<class ...> using __void_t = void’
634 | template<typename...> using __void_t = void;
| ^~~~~~~~
Mesh.ixx:14:29: note: during load of binding ‘VF::TVector@VF.Tensor’
14 | class TPoint final : public TVector<d> {};
| ^~~~~~~
Mesh.ixx:7:8: warning: not writing module ‘VF.Mesh’ due to errors
7 | export module VF.Mesh;
|
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