A "null" designator won't have a valid location. Try to approximate this
location as best we can in that situation.
Remove extraneous space.
Thank you for taking care of this, LGTM
nitpick, I think the comment should be above the if statement
Why are we rejecting this?
That's existing behavior: https://godbolt.org/z/48ThKbTor but we don't get the behavior when it's not a template (https://godbolt.org/z/f3zWaqdWr) or in C (https://godbolt.org/z/P1TqG43nG), so I agree that this should be accepted.
Also, if the "auto" above is changed to "int" this compiles just fine.