https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116714
Bug ID: 116714
Summary: [14 Regression] Inconsistent lambda type inference in
function template instance
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: ted at lyncon dot se
Target Milestone: ---
The lambda type `type` is here used to instantiate two objects, i1 and i2. They
are clearly of the same type since `std::is_same_v<decltype(i1), decltype(i2)>`
is `true` and they also use the same `static` variable, `x`.
However, `std::is_same_v<type, type>` is `false`:
```
#include <iostream>
#include <type_traits>
template<class = void> // remove this and all passes
void foo() {
using type = decltype([](){ static int x = 0; return ++x; });
type i1;
type i2;
// passes:
static_assert(std::is_same_v<decltype(i1), decltype(i2)>);
// does not pass:
static_assert(std::is_same_v<type, type>);
// prints 12 if static_assert above is removed:
std::cout << i1() << i2() << '\n';
};
int main() {
foo();
}
```
This seems to be a regression since gcc 13
