Ryan Scott <ryan.gl.scott@gmail.com> writes:

> I did a smoke test of Stackage Nightly's libraries [1] this afternoon using
> GHC 8.2.2. Only two libraries failed to build: extensible-0.4.5 and
> protolude-0.2, due to a change where type signatures like `foo :: forall k.
> forall (a :: k). ...` no longer compile without enabling TypeInType.
>
> I only mention this because the migration guide for 8.4 [2] currently gives
> the impression that this TypeInType change won't land until GHC 8.4. This
> doesn't appear to be case, though!
>
It sounds like you are describing #13391. If this is the case then I'm
rather confused since I didn't merge the associated patch. Something
else must be going on here. Perhaps some other patch made the checks a
bit more strict inadvertently?

Cheers,

- Ben