[null safety] Unhelpful error message on argument mismatch for inline call

[tobil4sk]

@:nullSafety
class Test {
  inline static function func(a:String, b:String) {
    return a + b;
  }
  
  static function main() {
    func(null, "");   
  }
}

[ERROR] Test.hx:8: characters 5-19

 8 |     func(null, "");   
   |     ^^^^^^^^^^^^^^
   | Null safety: Cannot assign nullable value here.

Compare with no inline:

[ERROR] Test.hx:8: characters 10-14

 8 |     func(null, "");   
   |          ^^^^
   | Null safety: Cannot pass nullable value to not-nullable argument "a" of function "func".

If it is a regular unification error, the message is the same for inline and non-inline, so hopefully the same could be achieved for null safety unification errors?

[RblSb]

At this point, all what null safety filter sees is var a = null; a + "";, so it can only be smarter if we mark inlined expressions with something like @:original_expr(...), run filter earlier someway, or reduce early inlinings.
So this issue is still about #7897 i guess

[tobil4sk]

I see, thanks for pointing to that issue!

I was wondering if for now it might be more useful if var a = null; could have the pos information of the original null rather than the whole expression, then at least the correct expression would be highlighted, even if the error is not right?