https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85808
Bug ID: 85808
Summary: [concepts] unqualified name lookup breaks after
qualified lookup in nested requirement
Product: gcc
Version: 8.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: Casey at Carter dot net
Target Milestone: ---
Compiling this program fragment with "g++ -std=c++17 -fconcepts"
(https://godbolt.org/g/EXDoD3):
namespace X {
template<class> constexpr bool x = true;
}
template<int> using helper = void;
template<typename T>
concept bool C = requires {
requires X::x<T>;
#ifndef WORKAROUND
typename helper<T{}>;
#else
typename ::helper<T{}>; // Workaround
#endif
};
static_assert(C<int>);
produces diagnostics:
<source>:11:14: error: 'X::helper' has not been declared
typename helper<T{}>;
^~~~~~
<source>:11:24: error: expected ';' before '>' token
typename helper<T{}>;
^
;
<source>:11:24: error: expected '}' before '>' token
<source>:8:27: note: to match this '{'
concept bool C = requires {
^
<source>:11:25: error: expected primary-expression before ';' token
typename helper<T{}>;
^
<source>:15:1: error: expected declaration before '}' token
};
^
rather than the expected successful and silent compile.
