| v `elemVarSet` tmpls
= -- v is a template variable
case lookupSubstEnv senv v of
- Nothing | typeKind ty == tyVarKind v
+ Nothing | typeKind ty `isSubKind` tyVarKind v
-- We do a kind check, just as in the uVarX above
-- The kind check is needed to avoid bogus matches
-- of (a b) with (c d), where the kinds don't match
match (FunTy arg1 res1) (FunTy arg2 res2) tmpls k senv
= match arg1 arg2 tmpls (match res1 res2 tmpls k) senv
+ -- If the template is an application, try to make the
+ -- thing we are matching look like an application
match (AppTy fun1 arg1) ty2 tmpls k senv
= case tcSplitAppTy_maybe ty2 of
Just (fun2,arg2) -> match fun1 fun2 tmpls (match arg1 arg2 tmpls k) senv
Nothing -> Nothing -- Fail
--- Newtypes are opaque; predicate types should not happen
+ -- Newtypes are opaque; predicate types should not happen
match (NewTcApp tc1 tys1) (NewTcApp tc2 tys2) tmpls k senv
| tc1 == tc2 = match_list_exactly tys1 tys2 tmpls k senv
match (TyConApp tc1 tys1) (TyConApp tc2 tys2) tmpls k senv