X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcTyFuns.lhs;h=5777955ed73cd5536c52baec3d4aa004a38b31b2;hb=e5a8d57c85d42007c8cc561e6d6b805c23603fc0;hp=77d72058c5cfb78142516231ff77a019f468bd13;hpb=cfda0421ca2c7c5f762814fd25988cf89871f1d8;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcTyFuns.lhs b/compiler/typecheck/TcTyFuns.lhs
index 77d7205..5777955 100644
--- a/compiler/typecheck/TcTyFuns.lhs
+++ b/compiler/typecheck/TcTyFuns.lhs
@@ -37,6 +37,7 @@ import Name
 import Bag
 import Outputable
 import SrcLoc	( Located(..) )
+import Util	( debugIsOn )
 import Maybes
 import FastString
 
@@ -69,21 +70,16 @@ tcUnfoldSynFamInst (TyConApp tycon tys)
   | not (isOpenSynTyCon tycon)     -- unfold *only* _synonym_ family instances
   = return Nothing
   | otherwise
-  = do { -- we only use the indexing arguments for matching, 
-         -- not the additional ones
-       ; maybeFamInst <- tcLookupFamInst tycon idxTys
+  = do { -- The TyCon might be over-saturated, but that's ok for tcLookupFamInst
+       ; maybeFamInst <- tcLookupFamInst tycon tys
        ; case maybeFamInst of
            Nothing                -> return Nothing
-           Just (rep_tc, rep_tys) -> return $ Just (mkTyConApp rep_tc tys',
-		                                    mkTyConApp coe_tc tys')
+           Just (rep_tc, rep_tys) -> return $ Just (mkTyConApp rep_tc rep_tys,
+		                                    mkTyConApp coe_tc rep_tys)
              where
-               tys'   = rep_tys ++ restTys
                coe_tc = expectJust "TcTyFuns.tcUnfoldSynFamInst" 
                                    (tyConFamilyCoercion_maybe rep_tc)
        }
-    where
-        n                = tyConArity tycon
-        (idxTys, restTys) = splitAt n tys
 tcUnfoldSynFamInst _other = return Nothing
 \end{code}
 
@@ -231,9 +227,6 @@ tcReduceEqs locals wanteds
 We maintain normalised equalities together with the skolems introduced as
 intermediates during flattening of equalities as well as 
 
-!!!TODO: We probably now can do without the skolem set.  It's not used during
-finalisation in the current code.
-
 \begin{code}
 -- |Configuration of normalised equalities used during solving.
 --
@@ -286,7 +279,15 @@ no further propoagation is possible.
 --
 normaliseEqs :: [Inst] -> TcM EqConfig
 normaliseEqs eqs 
-  = do { ASSERTM2( allM wantedEqInstIsUnsolved eqs, ppr eqs )
+  = do { if debugIsOn then do { all_unsolved <- allM wantedEqInstIsUnsolved eqs
+       	    	      	      ; let msg = ptext (sLit "(This warning is harmless; for Simon & Manuel)")
+       	    	      	      ; WARN( not all_unsolved, msg $$ ppr eqs ) return () }
+		      else return ()
+	    -- This is just a warning (not an error) because a current
+	    -- harmless bug means that we sometimes solve the same
+	    -- equality more than once It'll go away with the new
+	    -- solver. See Trac #2999 for example
+
        ; traceTc $ ptext (sLit "Entering normaliseEqs")
 
        ; (eqss, skolemss) <- mapAndUnzipM normEqInst eqs
@@ -384,9 +385,6 @@ families.  Moreover, in Forms (2) & (3), the left-hand side may not occur in
 the right-hand side, and the relation x > y is an arbitrary, but total order
 on type variables
 
-!!!TODO: We may need to keep track of swapping for error messages (and to
-re-orient on finilisation).
-
 \begin{code}
 data RewriteInst
   = RewriteVar  -- Form (2) above
@@ -960,9 +958,6 @@ applySubstFam eq1@(RewriteFam {rwi_fam = fam1, rwi_args = args1})
     -- rule matches => rewrite
   | fam1 == fam2 && tcEqTypes args1 args2 &&
     (isWantedRewriteInst eq2 || not (isWantedRewriteInst eq1))
--- !!!TODO: tcEqTypes is insufficient as it does not look through type synonyms
--- !!!Check whether anything breaks by making tcEqTypes look through synonyms.
--- !!!Should be ok and we don't want three type equalities.
   = do { co2' <- mkRightTransEqInstCo co2 co1 (lhs, rhs)
        ; eq2' <- deriveEqInst eq2 lhs rhs co2'
        ; liftM Just $ normEqInst eq2'
@@ -1240,7 +1235,7 @@ instantiateAndExtract eqs localsEmpty skolems
       | Just tv2 <- tcGetTyVar_maybe ty2
       , isMetaTyVar tv2
       , mayInst tv2 && (checkingMode || tv2 `elemVarSet` skolems)
-                        -- !!!TODO: this is too liberal, even if tv2 is in 
+                        -- !!!FIXME: this is too liberal, even if tv2 is in 
                         -- skolems we shouldn't instantiate if tvs occurs 
                         -- in other equalities that may propagate it into the
                         -- environment