Remove redundant dump

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

diff --git a/compiler/typecheck/TcExpr.lhs b/compiler/typecheck/TcExpr.lhs
index e6ab82b..e2f1d0c 100644 (file)
--- a/compiler/typecheck/TcExpr.lhs
+++ b/compiler/typecheck/TcExpr.lhs
@@ -21,7 +21,7 @@ import qualified DsMeta
 #endif
 
 import HsSyn           ( HsExpr(..), LHsExpr, ArithSeqInfo(..), recBindFields,
-                         HsMatchContext(..), HsRecordBinds, mkHsWrap,
+                         HsMatchContext(..), HsRecordBinds, mkHsWrap, hsExplicitTvs,
                          mkHsApp, mkLHsWrap )
 import TcHsSyn         ( hsLitType )
 import TcRnMonad
@@ -32,7 +32,7 @@ import BasicTypes     ( Arity, isMarkedStrict )
 import Inst            ( newMethodFromName, newIPDict, instCall,
                          newMethodWithGivenTy, instStupidTheta )
 import TcBinds         ( tcLocalBinds )
-import TcEnv           ( tcLookup, tcLookupDataCon, tcLookupField )
+import TcEnv           ( tcLookup, tcLookupDataCon, tcLookupField, tcExtendTyVarEnv2 )
 import TcArrows                ( tcProc )
 import TcMatches       ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcBody,
                          TcMatchCtxt(..) )
@@ -45,7 +45,7 @@ import TcType         ( TcType, TcSigmaType, TcRhoType, TvSubst,
                          mkTyVarTys, mkFunTys, 
                          tcMultiSplitSigmaTy, tcSplitFunTysN,
                          tcSplitTyConApp_maybe, 
-                         isSigmaTy, mkFunTy, mkTyConApp, isLinearPred,
+                         isSigmaTy, mkFunTy, mkTyConApp, 
                          exactTyVarsOfType, exactTyVarsOfTypes, 
                          zipTopTvSubst, zipOpenTvSubst, substTys, substTyVar
                        )
@@ -111,7 +111,7 @@ tcPolyExpr expr res_ty
 
 tcPolyExprNC expr res_ty 
   | isSigmaTy res_ty
-  = do { (gen_fn, expr') <- tcGen res_ty emptyVarSet (tcPolyExprNC expr)
+  = do { (gen_fn, expr') <- tcGen res_ty emptyVarSet (\_ -> tcPolyExprNC expr)
                -- Note the recursive call to tcPolyExpr, because the
                -- type may have multiple layers of for-alls
        ; return (mkLHsWrap gen_fn expr') }
@@ -208,9 +208,14 @@ tcExpr (HsLam match) res_ty
 
 tcExpr in_expr@(ExprWithTySig expr sig_ty) res_ty
  = do  { sig_tc_ty <- tcHsSigType ExprSigCtxt sig_ty
-       ; expr' <- tcPolyExpr expr sig_tc_ty
+
+       -- Remember to extend the lexical type-variable environment
+       ; (gen_fn, expr') <- tcGen sig_tc_ty emptyVarSet (\ skol_tvs res_ty ->
+                            tcExtendTyVarEnv2 (hsExplicitTvs sig_ty `zip` mkTyVarTys skol_tvs) $
+                            tcPolyExprNC expr res_ty)
+
        ; co_fn <- tcSubExp sig_tc_ty res_ty
-       ; return (mkHsWrap co_fn (ExprWithTySigOut expr' sig_ty)) }
+       ; return (mkHsWrap co_fn (ExprWithTySigOut (mkLHsWrap gen_fn expr') sig_ty)) }
 
 tcExpr (HsType ty) res_ty
   = failWithTc (text "Can't handle type argument:" <+> ppr ty)
@@ -796,19 +801,9 @@ instFun orig fun subst tv_theta_prs
        = do { co_fn <- instCall orig tys theta
             ; go False (HsWrap co_fn fun) prs }
 
-       --      Hack Alert (want_method_inst)!
        -- See Note [No method sharing]
-       -- If   f :: (%x :: T) => Int -> Int
-       -- Then if we have two separate calls, (f 3, f 4), we cannot
-       -- make a method constraint that then gets shared, thus:
-       --      let m = f %x in (m 3, m 4)
-       -- because that loses the linearity of the constraint.
-       -- The simplest thing to do is never to construct a method constraint
-       -- in the first place that has a linear implicit parameter in it.
-    want_method_inst theta =  not (null theta)                 -- Overloaded
-                          && not (any isLinearPred theta)      -- Not linear
+    want_method_inst theta =  not (null theta) -- Overloaded
                           && not opt_NoMethodSharing
-               -- See Note [No method sharing] below
 \end{code}
 
 Note [Multiple instantiation]