Crystal: BUG: trying to upcast (Proc(Nil) | Nil) <- (Proc(String) | Nil) (Exception)

[docelic]

Here's code that causes a compiler exception:

def create_proc(b : String)

  if true
    begin
       ->(){""}
    rescue
      return ->(){}
    end
  end
end

create_proc "X"

(Also on https://play.crystal-lang.org/#/r/7y27 )

I was able to trigger this issue only in this somewhat narrow set of conditions -- an if, with a begin block, with the begin part not having return, while rescue do having it, and with the proc signature being different.

[rmarronnier]

Appears to be fixed : https://carc.in/#/r/990k

[jhass]

Let's add the example as a spec.