https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126233
--- Comment #6 from Ivan Lazaric <ivan.lazaric.gcc at gmail dot com> ---
I applied your patch locally, consider the following example:
```cpp
#include <source_location>
#include <format>
consteval bool check(std::source_location loc) {
__builtin_constexpr_diag(0, "", std::format("line: {}", loc.line()));
__builtin_constexpr_diag(0, "", std::format("func: {}",
loc.function_name()));
return true;
}
template<auto B = check(std::source_location::current())>
void fn1() {}
int main() {
fn1();
auto lambda = []<auto B = check(std::source_location::current())> {};
lambda();
}
```
Compiler output (modulo constexpr backtraces):
```
constexpr message: line: 10
constexpr message: func:
constexpr message: line: 16
constexpr message: func:
```
It seems to do the right thing for `fn1()`
(though I personally would find `{14, "int main()"}` behaviour more useful).
The last line, function name from the source location in lambda template
default argument,
should probably be `int main()`
