Clean up some comments

[ghc-hetmet.git] / compiler / typecheck / TcTyFuns.lhs

diff --git a/compiler/typecheck/TcTyFuns.lhs b/compiler/typecheck/TcTyFuns.lhs
index 3f3a7c9..2237e3f 100644 (file)
--- a/compiler/typecheck/TcTyFuns.lhs
+++ b/compiler/typecheck/TcTyFuns.lhs
@@ -231,9 +231,6 @@ tcReduceEqs locals wanteds
 We maintain normalised equalities together with the skolems introduced as
 intermediates during flattening of equalities as well as 
 
 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.
 --
 \begin{code}
 -- |Configuration of normalised equalities used during solving.
 --

@@ -286,7 +283,7 @@ no further propoagation is possible.
 --
 normaliseEqs :: [Inst] -> TcM EqConfig
 normaliseEqs eqs 
 --
 normaliseEqs :: [Inst] -> TcM EqConfig
 normaliseEqs eqs 

-  = do { ASSERTM2( allM isValidWantedEqInst eqs, ppr eqs )
+  = do { ASSERTM2( allM wantedEqInstIsUnsolved eqs, ppr eqs )

        ; traceTc $ ptext (sLit "Entering normaliseEqs")
 
        ; (eqss, skolemss) <- mapAndUnzipM normEqInst eqs
        ; traceTc $ ptext (sLit "Entering normaliseEqs")
 
        ; (eqss, skolemss) <- mapAndUnzipM normEqInst eqs

@@ -352,7 +349,7 @@ finaliseEqsAndDicts (EqConfig { eqs     = eqs
 
          -- Assert that all cotvs of wanted equalities are still unfilled, and
          -- zonk all final insts, to make any improvement visible
 
          -- Assert that all cotvs of wanted equalities are still unfilled, and
          -- zonk all final insts, to make any improvement visible

-       ; ASSERTM2( allM isValidWantedEqInst eqs'', ppr eqs'' )
+       ; ASSERTM2( allM wantedEqInstIsUnsolved eqs'', ppr eqs'' )

        ; zonked_locals  <- zonkInsts locals'
        ; zonked_wanteds <- zonkInsts (eqs'' ++ wanteds')
        ; return (zonked_locals, zonked_wanteds, final_binds, improved)
        ; zonked_locals  <- zonkInsts locals'
        ; zonked_wanteds <- zonkInsts (eqs'' ++ wanteds')
        ; return (zonked_locals, zonked_wanteds, final_binds, improved)

@@ -384,9 +381,6 @@ 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
 
 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
 \begin{code}
 data RewriteInst
   = RewriteVar  -- Form (2) above

@@ -960,9 +954,6 @@ applySubstFam eq1@(RewriteFam {rwi_fam = fam1, rwi_args = args1})
     -- rule matches => rewrite
   | fam1 == fam2 && tcEqTypes args1 args2 &&
     (isWantedRewriteInst eq2 || not (isWantedRewriteInst eq1))
     -- 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'
   = do { co2' <- mkRightTransEqInstCo co2 co1 (lhs, rhs)
        ; eq2' <- deriveEqInst eq2 lhs rhs co2'
        ; liftM Just $ normEqInst eq2'

@@ -1240,7 +1231,7 @@ instantiateAndExtract eqs localsEmpty skolems
       | Just tv2 <- tcGetTyVar_maybe ty2
       , isMetaTyVar tv2
       , mayInst tv2 && (checkingMode || tv2 `elemVarSet` 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
                         -- skolems we shouldn't instantiate if tvs occurs 
                         -- in other equalities that may propagate it into the
                         -- environment