improve error report use SourceLoc

[illusory0x0]

fn print_loc(loc~ : SourceLoc = _) -> Unit{
  let loc = loc.to_string().escape()
  println(loc)
}

test "forall" {
  println("\n\n")
  println("loc: ")
  print_loc()
  println("\n\n")

}

This function prints the location where this function was called.

We can refer to the implementation of inspect!

[illusory0x0]

Continue in #1599