A (final) re-engineering of the new typechecker

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

diff --git a/compiler/typecheck/Inst.lhs b/compiler/typecheck/Inst.lhs
index eefc424..e1f3fb7 100644 (file)
--- a/compiler/typecheck/Inst.lhs
+++ b/compiler/typecheck/Inst.lhs
@@ -37,7 +37,6 @@ import HsSyn
 import TcHsSyn
 import TcRnMonad
 import TcEnv
-import TcRnTypes
 import InstEnv
 import FunDeps
 import TcMType
@@ -89,7 +88,7 @@ newMethodFromName :: CtOrigin -> Name -> TcRhoType -> TcM (HsExpr TcId)
 newMethodFromName origin name inst_ty
   = do { id <- tcLookupId name
              -- Use tcLookupId not tcLookupGlobalId; the method is almost
-             -- always a class op, but with -XNoImplicitPrelude GHC is
+             -- always a class op, but with -XRebindableSyntax GHC is
              -- meant to find whatever thing is in scope, and that may
              -- be an ordinary function. 
 
@@ -295,7 +294,7 @@ mkOverLit (HsIsString s) = return (HsString s)
 %*                                                                     *
 %************************************************************************
 
-Suppose we are doing the -XNoImplicitPrelude thing, and we encounter
+Suppose we are doing the -XRebindableSyntax thing, and we encounter
 a do-expression.  We have to find (>>) in the current environment, which is
 done by the rename. Then we have to check that it has the same type as
 Control.Monad.(>>).  Or, more precisely, a compatible type. One 'customer' had
@@ -474,11 +473,9 @@ hasEqualities :: [EvVar] -> Bool
 -- Has a bunch of canonical constraints (all givens) got any equalities in it?
 hasEqualities givens = any (has_eq . evVarPred) givens
   where
-    has_eq (EqPred {})             = True
-    has_eq (IParam {})             = False
-    has_eq (ClassP cls tys) = any has_eq (substTheta subst (classSCTheta cls))
-      where
-        subst = zipOpenTvSubst (classTyVars cls) tys
+    has_eq (EqPred {})              = True
+    has_eq (IParam {})              = False
+    has_eq (ClassP cls _tys) = any has_eq (classSCTheta cls)
 
 ----------------
 tyVarsOfWanteds :: WantedConstraints -> TyVarSet