https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92040
Bug ID: 92040
Summary: Type requirements don't appear to work when a type
doesn't exist.
Product: gcc
Version: 10.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: cjdb.ns at gmail dot com
Target Milestone: ---
Created attachment 47011
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47011&action=edit
Requested file
# GCC version
g++ (GCC) 10.0.0 20191009 (experimental)
# System type
Ubuntu on WSL
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 19.04
Release: 19.04
Codename: disco
# GCC built with
export CC=/usr/bin/clang-9
export CXX=/usr/bin/clang++-9
export CFLAGS='-w -O3 -DNDEBUG -g0 -fdiagnostics-color=always -fuse-ld=lld'
export CXXFLAGS='-w -O3 -DNDEBUG -g0 -fdiagnostics-color=always -fuse-ld=lld'
export LDFLAGS='-fuse-ld=lld'
../gcc/configure --enable-languages=c,c++ \
--disable-bootstrap \
--disable-libada \
--disable-libgomp \
--disable-libquadmath \
--disable-libquadmath-support \
--disable-multilib \
--disable-nls \
--disable-werror
make -j6
sudo make install-strip -j6
# Minimal repro
```cpp
template<typename T>
constexpr void example()
{
constexpr auto result = requires { typename T::value_type; };
static_assert(not result);
}
int main()
{
struct s{};
example<s>();
}
```
Built using: /usr/local/bin/g++ -std=c++2a test.cpp
# Diagnostic
```
test.cpp: In instantiation of 'constexpr void example() [with T = main()::s]':
test.cpp:11:15: required from here
test.cpp:4:49: error: no type named 'value_type' in 'struct main()::s'
4 | constexpr auto result = requires { typename T::value_type; };
|
```
