Re: [Sml-implementers] type-checking bug in several implementations

[Andreas R. <And...@we...>]

Nick Benton <ni...@mi...> wrote:
>
> SML.NET rejects it, though the error message leaves room for
> improvement!

Alice also rejects it, with a halfway decent error message:

1.10-12.4: module expression does not match signature:
   val f : '1 option -> '1 option
does not match
   val f : 'a option -> 'a option
because
   '1
is incompatible with
   '_a

Actually, I fixed this only a couple of months ago, using some variable
level hack. Somehow I forgot to double-check Hamlet on this occasion. I
doubt that I can use the same hack there.

    - Andreas