https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112448
Bug ID: 112448
Summary: Constraint expression b<x.v> rejected
Product: gcc
Version: 13.2.1
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 s { static constexpr bool v = true; };
template<auto> inline constexpr bool b = true;
constexpr bool f(auto x) requires b<x.v> { return true; }
static_assert(f(s{})); // clang ok, gcc nope, msvc ok
is valid per the explanation here https://stackoverflow.com/a/77439003/7325599
but GCC rejects it with the error:
missing template arguments before '<' token
3 | constexpr bool f(auto x) requires b<x.v> { return true; }
| ^
<source>:3:36: error: expected initializer before '<' token
<source>:4:15: error: 'f' was not declared in this scope
4 | static_assert(f(s{}));
Online demo: https://godbolt.org/z/1Gejvr4cn
