Unresolved TApp during inference

[benl]

Added by Jared

example list = do
    dummy = map id list
    list.head

Gives

ddc: PANIC in Type.Squid.CrushProj
        crushProjClassT: no match for (* -> *)20 *24

The example succeeds when the projection is removed in favor of its corresponding function. The example also fails for variants using let and where and when dummy is removed. If dummy is replaced by an underscore, the failure message is the same for a do block, but let and where clauses trigger a different compiler error.

Type.Crush.Proj.crushProjClass3 is expecting a fully formed TData - but the result type of map is a TApp which it gets from the sig in the Functor class definition.

Test is T75-UnresolvedTApp

[benl]

Fixed by the inferencer refactoring.