https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88515
Bug ID: 88515
Summary: [concepts] id-expression that names non-static data
member rejected in requires-expression
Product: gcc
Version: 9.0
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 TU:
template<class T> concept bool C =
requires { T::value; };
struct S { int value; };
static_assert(C<S>);
with "g++ -std=c++2a -fconcepts -c" produces:
/home/casey/casey/Desktop/repro2.cpp:5:15: error: invalid use of non-static
data member ‘S::value’
5 | static_assert(C<S>);
| ^~~~
/home/casey/casey/Desktop/repro2.cpp:4:16: note: declared here
4 | struct S { int value; };
| ^~~~~
/home/casey/casey/Desktop/repro2.cpp:5:15: error: static assertion failed
5 | static_assert(C<S>);
|
when it should compile successfully since an id-expression that denotes a
non-static data member can appear in an unevaluated operand
([expr.prim.id]/2.3) and expressions appearing within a requirement-body are
unevaluated operands ([expr.prim.req]/2).
