[Bug libstdc++/116889] New: source_location line number off-by-one when implicitly converting to a type with a defaulted source_location argument

[oliver.rosten at googlemail dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116889

            Bug ID: 116889
           Summary: source_location line number off-by-one when implicitly
                    converting to a type with a defaulted source_location
                    argument
           Product: gcc
           Version: 14.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: oliver.rosten at googlemail dot com
  Target Milestone: ---

#include <iostream>
#include <source_location>

struct report{
    report(const char*, std::source_location
loc=std::source_location::current()) {
       std::cout << loc.line() << '\n';
    }
};

void check(int, report r) {};

int main() {
    check(42, 
          ""); // Incorrectly reports line 20 (one above)

    check(42, 
          report{""}); // Correctly reports line 24
}

https://godbolt.org/z/vz4Y4xanP