Function type in return type position not parsed correctly?

[osa1]

fun weird-syntax1(cb: () -> string): string
  cb()

The function is parsed and checked as expected.

If I move the argument type to the return type position:

fun weird-syntax2(): () -> string
  fn() ""

It generates this error:

test.kk(202,28): type error: identifier string cannot be resolved.
  context      :                            string
  inferred type: _
  candidates   : sslice/string         : (slice : sslice/sslice) -> string
                 string/listchar/string: (cs : list<char>) -> string
                 string/maybe/string   : (ms : maybe<string>) -> string
                 string/vector/string  : (vector<char>) -> string
                 string/char/string    : (c : char) -> string
  hint         : give a type annotation or qualify the name?

Since string is clearly defined, I wonder if this is a parse error and string is not parsed as a type identifier?

[TimWhiting]

I typically add parentheses to function types in return position to make it clear, or create an alias for it.

[chtenb]

I had run into this behavior before. Could we consider making the grammar slightly more flexible to not require these extra parentheses? I think that is a more natural way to write the type, and I expect many new people will run into this.