https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122400
Bug ID: 122400
Summary: qualified friend declaration doesn't search names in
the declared scope
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ykakeyama3014 at gmail dot com
Target Milestone: ---
Following code is rejected by GCC trunk:
namespace outer {
namespace inner {
inline constexpr bool foo = true;
using bar = int;
} // namespace inner
auto func() noexcept(inner::foo) -> inner::bar;
namespace inner {
struct S {
friend auto outer::func() noexcept(foo) -> bar;
};
} // namespace inner
} // namespace outer
Errors are follows:
source.cpp:16:38: error: ‘foo’ was not declared in this scope; did you mean
‘outer::inner::foo’?
16 | friend auto outer::func() noexcept(foo) -> bar;
| ^~~
| outer::inner::foo
source.cpp:5:23: note: ‘outer::inner::foo’ declared here
5 | inline constexpr bool foo = true;
| ^~~
source.cpp:16:46: error: ‘bar’ does not name a type
16 | friend auto outer::func() noexcept(foo) -> bar;
| ^~~
In the qualified friend declaration, name lookup should search ::outer first
and then ::outer::inner according to [basic.lookup.unqual]#6. However, it seems
GCC currently searches only the first case, not searching ::outer::inner.
