[jhc] explanation of FrontEnd.KindInfer.constrain

[Samuel Bronson]

On 3/18/08, John Meacham <john at repetae.net> wrote:

> 'constrain' refines a type subject to constraints, kindCombine actually
> returns what the unification of the kinds are. constrain works on
> constraints, combine works on kinds. constraints don't necessarily map
> to kinds, though currently most have an analog.

Eh? Doesn't KindInfer run before typechecking begins?