https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104620
--- Comment #7 from Patrick Palka <ppalka at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #4)
> This one is valid, but before your r12-7264 was incorrectly rejected because
> 8 * baz (0) etc. is wrapped in NON_DEPENDENT_EXPR,
> potential_constant_expression_1 recursed on the NON_DEPENDENT_EXPR operand,
> found it is ok but cxx_eval_constant_expression
> rejected the NON_DEPENDENT_EXPR.
Makes sense, similar to the #2 case in comment #5.
> Bet for the build_over_call
> processing_template_decl immediate_invocation_p code we need to punt
> silently if there is something we can't handle but fail loudly if we can
> handle everything but it is clearly always not a constant expression.
> potential_constant_expression_1 isn't 100% accurate, there are cases where
> it gets stuff through.
IIUC as long as NON_DEPENDENT_EXPR doesn't appear inside a non-dependent
consteval call then we'll currently correctly accept/reject it ahead of time,
e.g.:
consteval int foo(int x) { return x; }
template<class>
void bar(int x)
{
constexpr int y = 0;
foo(x); // error: 'x' is not a constant expression
foo(y); // OK
foo(x * 1); // no (ahead of time) error due to NON_DEPENDENT_EXPR
}
