Error when using named argument on trailing macro body expansion

[cbuttner]

macro @foo(; @body(int arg)) {
  @body(arg: 0);
}

fn void main() {
  @foo(; int arg) {};
}

⚠️ The compiler encountered an unexpected error: "Should be unreachable".

[lerno]

It shouldn't be allowed in the first place. This should be fixed now.

[cbuttner]

Looks good to me.