https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101013
Bug ID: 101013
Summary: Rejects-valid for alias template in a different
namespace with a lambda in unevaluated context
Product: gcc
Version: 11.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: tartanllama at gmail dot com
Target Milestone: ---
Code:
namespace ns {
template <class T>
using void_t = decltype([]{}());
}
template<class T>
struct oh_no {
using type = ns::void_t<T>;
};
Compiler output:
<source>:8:22: error: '<expression error>' in namespace 'ns' does not name a
type
8 | using type = ns::void_t<T>;
| ^~~~~~~~~
Expected behaviour:
Compile cleanly
Additional information:
The code compiles if oh_no and void_t are in the same namespace
GCC version and configuration options:
GCC 11.1.0
../gcc-11.1.0/configure --prefix=/opt/compiler-explorer/gcc-build/staging
--build=x86_64-linux-gnu --host=x86_64-linux-gnu --target=x86_64-linux-gnu
--disable-bootstrap --enable-multiarch --with-abi=m64
--with-multilib-list=m32,m64,mx32 --enable-multilib --enable-clocale=gnu
--enable-languages=c,c++,fortran,ada,go,d --enable-ld=yes --enable-gold=yes
--enable-libstdcxx-debug --enable-libstdcxx-time=yes --enable-linker-build-id
--enable-lto --enable-plugins --enable-threads=posix
--with-pkgversion=Compiler-Explorer-Build
Command line:
-std=c++20
Compiler explorer link:
https://godbolt.org/z/EYsbbjodj
