https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110497
Bug ID: 110497
Summary: Wrong error on non-static data member referenced in
concept definition
Product: gcc
Version: 13.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: fchelnokov at gmail dot com
Target Milestone: ---
This program
struct B {
const bool b = true;
};
template <typename T>
concept C = T::b;
static_assert( !C<B> );
is accepted in Clang. And I think correctly accepted because of substitution
failure per https://eel.is/c++draft/temp.constr.constr#temp.constr.op-5
> [...] Furthermore, if substitution to determine whether an atomic constraint
> is satisfied ([temp.constr.atomic]) encounters a substitution failure, the
> constraint is not satisfied, regardless of the presence of a negation
> operator.
But GCC emits a weird error (at least the error text must be adjusted):
error: '*(B*)(void)0' is not a constant expression
Online demo: https://gcc.godbolt.org/z/xKf13cb6v
