Minor refactoring plus comments

compiler/typecheck/TcMType.lhs

@@ -542,21 +542,23 @@ zonkQuantifiedTyVars :: [TcTyVar] -> TcM [TcTyVar]
 -- A kind variable k may occur *after* a tyvar mentioning k in its kind
 zonkQuantifiedTyVars tyvars
   = do { let (kvs, tvs) = partition isKindVar tyvars
-       ; poly_kinds <- xoptM Opt_PolyKinds
-       ; if poly_kinds then
-             mapM zonkQuantifiedTyVar (kvs ++ tvs)
-           -- Because of the order, any kind variables
-           -- mentioned in the kinds of the type variables refer to
-           -- the now-quantified versions
-         else
+             (meta_kvs, skolem_kvs) = partition isMetaTyVar kvs
+
              -- In the non-PolyKinds case, default the kind variables
              -- to *, and zonk the tyvars as usual.  Notice that this
              -- may make zonkQuantifiedTyVars return a shorter list
              -- than it was passed, but that's ok
-             do { let (meta_kvs, skolem_kvs) = partition isMetaTyVar kvs
-                ; WARN ( not (null skolem_kvs), ppr skolem_kvs )
-                  mapM_ defaultKindVarToStar meta_kvs
-                ; mapM zonkQuantifiedTyVar (skolem_kvs ++ tvs) } }
+       ; poly_kinds <- xoptM Opt_PolyKinds
+       ; qkvs <- if poly_kinds 
+                 then return kvs
+                 else WARN ( not (null skolem_kvs), ppr skolem_kvs )
+                      do { mapM_ defaultKindVarToStar meta_kvs
+                         ; return skolem_kvs }  -- Should be empty
+
+       ; mapM zonkQuantifiedTyVar (qkvs ++ tvs) }
+           -- Because of the order, any kind variables
+           -- mentioned in the kinds of the type variables refer to
+           -- the now-quantified versions
 
 zonkQuantifiedTyVar :: TcTyVar -> TcM TcTyVar
 -- The quantified type variables often include meta type variables

compiler/typecheck/TcTyClsDecls.lhs

@@ -900,11 +900,11 @@ tcFamTyPats fam_tc (HsWB { hswb_cts = arg_pats, hswb_kvs = kvars, hswb_tvs = tva
                       ; tcHsArgTys (quotes (ppr fam_tc)) arg_pats arg_kinds }
        ; let all_args = fam_arg_kinds ++ typats
 
-            -- Find free variables (after zonking)
-       ; tkvs <- zonkTyVarsAndFV (tyVarsOfTypes all_args)
-
-            -- Turn them into skolems, so that we don't subsequently 
+            -- Find free variables (after zonking) and turn
+            -- them into skolems, so that we don't subsequently 
             -- replace a meta kind var with AnyK
+            -- Very like kindGeneralize
+       ; tkvs <- zonkTyVarsAndFV (tyVarsOfTypes all_args)
        ; qtkvs <- zonkQuantifiedTyVars (varSetElems tkvs)
 
             -- Zonk the patterns etc into the Type world
@@ -912,7 +912,7 @@ tcFamTyPats fam_tc (HsWB { hswb_cts = arg_pats, hswb_kvs = kvars, hswb_tvs = tva
        ; all_args'    <- zonkTcTypeToTypes ze all_args
        ; res_kind'    <- zonkTcTypeToType  ze res_kind
 
-       ; traceTc "tcFamPats" (pprTvBndrs qtkvs' $$ ppr all_args' $$ ppr res_kind')
+       ; traceTc "tcFamTyPats" (pprTvBndrs qtkvs' $$ ppr all_args' $$ ppr res_kind')
        ; tcExtendTyVarEnv qtkvs' $
          thing_inside qtkvs' all_args' res_kind' }
 \end{code}
@@ -1070,7 +1070,7 @@ tcConDecl new_or_data rep_tycon res_tmpl 	-- Data types
                 -- free kind variables of the type, for kindGeneralize to work on
 
              -- Generalise the kind variables (returning quantifed TcKindVars)
-             -- and quanify the type variables (substiting their kinds)
+             -- and quantify the type variables (substiting their kinds)
        ; kvs <- kindGeneralize (tyVarsOfType pretend_con_ty) (map getName tvs)
        ; tvs <- zonkQuantifiedTyVars tvs