https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99214
Bug ID: 99214
Summary: Incorrect template arguments shown in constraint
satisfaction failure diagnostic
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ppalka at gcc dot gnu.org
Target Milestone: ---
$ cat testcase.C
template <class T>
struct A {
template <class U> static void f() requires ([] { return U::fail; }());
template <class U> static void f();
};
int main() {
A<int>::f<char>();
}
$ cat testcase.C | g++-11 -std=c++20 -x c++ -
<stdin>: In substitution of ‘template<class U> static void A<int>::f<U>()
requires (<lambda>)() [with U = int]’:
<stdin>:8:19: required from here
<stdin>:3:63: error: ‘fail’ is not a member of ‘char’
In the above diagnostic, the "in substitution of" context line incorrectly
shows "U = int" instead of "U = char".
GCC 10 shows the correct template arguments:
$ cat testcase.C | g++-10 -std=c++20 -x c++ -
<stdin>: In instantiation of ‘static void A<T>::f() requires (<lambda>)() [with
U = char; T = int]’:
<stdin>:8:19: required from here
<stdin>:3:63: error: ‘fail’ is not a member of ‘char’
