The final batch of changes for the new coercion representation

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

diff --git a/compiler/typecheck/TcEnv.lhs b/compiler/typecheck/TcEnv.lhs
index 4b5730b..a087059 100644 (file)
--- a/compiler/typecheck/TcEnv.lhs
+++ b/compiler/typecheck/TcEnv.lhs
@@ -203,6 +203,7 @@ tcLookupFamInst tycon tys
   = do { env <- getGblEnv
        ; eps <- getEps
        ; let instEnv = (eps_fam_inst_env eps, tcg_fam_inst_env env)
+       ; traceTc "lookupFamInst" ((ppr tycon <+> ppr tys) $$ ppr instEnv)
        ; case lookupFamInstEnv instEnv tycon tys of
           []                      -> return Nothing
           ((fam_inst, rep_tys):_) 
@@ -625,7 +626,7 @@ data InstBindings a
                        -- witness dictionary is identical to the argument 
                        -- dictionary.  Hence no bindings, no pragmas.
 
-       CoercionI       -- The coercion maps from newtype to the representation type
+       Coercion        -- The coercion maps from newtype to the representation type
                        -- (mentioning type variables bound by the forall'd iSpec variables)
                        -- E.g.   newtype instance N [a] = N1 (Tree a)
                        --        co : N [a] ~ Tree a
@@ -637,7 +638,13 @@ data InstBindings a
                         -- in TcDeriv
 
 pprInstInfo :: InstInfo a -> SDoc
-pprInstInfo info = vcat [ptext (sLit "InstInfo:") <+> ppr (idType (iDFunId info))]
+pprInstInfo info = hang (ptext (sLit "instance"))
+                      2 (sep [ ifPprDebug (pprForAll tvs)
+                             , pprThetaArrowTy theta, ppr tau
+                             , ptext (sLit "where")])
+  where
+    (tvs, theta, tau) = tcSplitSigmaTy (idType (iDFunId info))
+
 
 pprInstInfoDetails :: OutputableBndr a => InstInfo a -> SDoc
 pprInstInfoDetails info = pprInstInfo info $$ nest 2 (details (iBinds info))