Can't leave off type parameters in tag patterns

[marijnh]

I.e.

alt (expr) {
  case (some(?thing)) {}
  case (none) {}
}

won't typecheck without explicit type params. The type of expr should contain enough information to deduce the type params.

[graydon]

I think this might have been fixed. Still seeing it?

[marijnh]

Yes, it still happens. Self-contained testcase:

tag maybe[T] {
    nothing;
    just(T);
}
fn foo(maybe[int] x) {
    alt (x) {
        case (nothing) {log_err "A";}
        case (just(?a)) {log_err "B";}
    }
}