Tightening up on inferred type signatures

[David Mazieres]

Simon Peyton Jones <simonpj at microsoft.com> writes:

> GHC generally obeys this rule
>
> * If GHC infers a type f::type, then it's OK for you to add a type
> signature saying exactly that.

Independent of language extensions, what about types and classes whose
names are not in scope.  Is there an implicit "... if you import all the
relevant symbols" and the end of the rule?

David