https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99961
Bug ID: 99961
Summary: requires clause rejects mentioning of function
parameters too early
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: nickgray0 at brown dot edu
Target Milestone: ---
the following code fails to compile:
struct A {
static constexpr auto x = 42;
};
auto f(auto a) requires (a.x > 10) {}
auto main()->int {
f(A{});
}
error message: <source>:5:27: error: use of parameter outside function body
before '.' token
5 | auto f(auto a) requires (a.x > 10) {}
| ^
<source>: In function 'int main()':
<source>:8:6: error: no matching function for call to 'f(A)'
8 | f(A{});
| ~^~~~~
<source>:5:6: note: candidate: 'template<class auto:1> auto f(auto:1) requires
<erroneous-expression>'
5 | auto f(auto a) requires (a.x > 10) {}
| ^
<source>:5:6: note: template argument deduction/substitution failed:
<source>:5:6: note: constraints not satisfied
as shown in the example above, a.x doesn't *actually* make use of a
