https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99546
Jonathan Wakely <redi at gcc dot gnu.org> changed:
What |Removed |Added
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Last reconfirmed|2021-08-16 00:00:00 |2022-9-20
--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
(In reply to 康桓瑋 from comment #1)
> You can see more weird cases in this:
> https://stackoverflow.com/questions/66578966/weird-return-value-of-c20-
> requires-expression.
Copying that here instead of linking to impermanent SO comments:
template <bool b>
void foo() {
static_assert(b);
}
int main() {
constexpr bool b = requires { []{}; };
foo<!b>();
foo<b>();
}
The bool appears to not be a constant expression:
x.C: In function 'int main()':
x.C:8:10: error: no matching function for call to 'foo<(!(bool)b)>()'
8 | foo<!b>();
| ~~~~~~~^~
x.C:2:6: note: candidate: 'template<bool b> void foo()'
2 | void foo() {
| ^~~
x.C:2:6: note: template argument deduction/substitution failed:
x.C:9:9: error: no matching function for call to 'foo<b>()'
9 | foo<b>();
| ~~~~~~^~
x.C:2:6: note: candidate: 'template<bool b> void foo()'
2 | void foo() {
| ^~~
x.C:2:6: note: template argument deduction/substitution failed:
