• Richard Eisenberg's avatar
    Fix #12442. · 9766b0c8
    Richard Eisenberg authored
    The problem is described in the ticket.
    
    This patch adds new variants of the access points to the pure
    unifier that allow unification of types only when the caller
    wants this behavior. (The unifier used to also unify kinds.)
    This behavior is appropriate when the kinds are either already
    known to be the same, or the list of types provided are a
    list of well-typed arguments to some type constructor. In the
    latter case, unifying earlier types in the list will unify the
    kinds of any later (dependent) types.
    
    At use sites, I went through and chose the unification function
    according to the criteria above.
    
    This patch includes some modest performance improvements as we
    are now doing less work.
    9766b0c8
TcSimplify.hs 90.2 KB