X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=ghc%2Fcompiler%2FdeSugar%2FDsGRHSs.lhs;h=0aef3a6e4ded048a09524efaecb5f13c373d82e3;hb=538cf5105b079fa779b612c6154db2bb4febb586;hp=e413c58e81a18aac41eb8ad3f1840b6823733a7c;hpb=495ef8bd9ef30bffe50ea399b91e3ba09646b59a;p=ghc-hetmet.git

diff --git a/ghc/compiler/deSugar/DsGRHSs.lhs b/ghc/compiler/deSugar/DsGRHSs.lhs
index e413c58..0aef3a6 100644
--- a/ghc/compiler/deSugar/DsGRHSs.lhs
+++ b/ghc/compiler/deSugar/DsGRHSs.lhs
@@ -11,16 +11,17 @@ module DsGRHSs ( dsGuarded, dsGRHSs ) where
 import {-# SOURCE #-} DsExpr  ( dsExpr, dsLet )
 import {-# SOURCE #-} Match   ( matchSinglePat )
 
-import HsSyn		( Stmt(..), HsExpr(..), GRHSs(..), GRHS(..) )
-import TcHsSyn		( TypecheckedGRHSs, TypecheckedPat, TypecheckedStmt )
-import CoreSyn		( CoreExpr, Bind(..) )
+import HsSyn		( Stmt(..), HsExpr(..), GRHSs(..), GRHS(..), HsMatchContext(..) )
+import TcHsSyn		( TypecheckedGRHSs, TypecheckedPat, TypecheckedStmt, TypecheckedMatchContext )
+import CoreSyn		( CoreExpr )
 import Type		( Type )
 
 import DsMonad
 import DsUtils
+import Unique		( Uniquable(..) )
 import PrelInfo		( nON_EXHAUSTIVE_GUARDS_ERROR_ID )
-import Unique		( otherwiseIdKey, trueDataConKey, hasKey, Uniquable(..) )
-import Outputable
+import TysWiredIn	( trueDataConId )
+import PrelNames	( otherwiseIdKey, hasKey )
 \end{code}
 
 @dsGuarded@ is used for both @case@ expressions and pattern bindings.
@@ -38,7 +39,7 @@ necessary.  The type argument gives the type of the @ei@.
 dsGuarded :: TypecheckedGRHSs -> DsM CoreExpr
 
 dsGuarded grhss
-  = dsGRHSs PatBindMatch [] grhss 				`thenDs` \ (err_ty, match_result) ->
+  = dsGRHSs PatBindRhs [] grhss 				`thenDs` \ (err_ty, match_result) ->
     mkErrorAppDs nON_EXHAUSTIVE_GUARDS_ERROR_ID err_ty ""	`thenDs` \ error_expr ->
     extractMatchResult match_result error_expr
 \end{code}
@@ -46,11 +47,11 @@ dsGuarded grhss
 In contrast, @dsGRHSs@ produces a @MatchResult@.
 
 \begin{code}
-dsGRHSs :: DsMatchKind -> [TypecheckedPat]	-- These are to build a MatchContext from
-	-> TypecheckedGRHSs			-- Guarded RHSs
+dsGRHSs :: TypecheckedMatchContext -> [TypecheckedPat]	-- These are to build a MatchContext from
+	-> TypecheckedGRHSs				-- Guarded RHSs
 	-> DsM (Type, MatchResult)
 
-dsGRHSs kind pats (GRHSs grhss binds (Just ty))
+dsGRHSs kind pats (GRHSs grhss binds ty)
   = mapDs (dsGRHS kind pats) grhss		`thenDs` \ match_results ->
     let 
 	match_result1 = foldr1 combineMatchResults match_results
@@ -75,17 +76,23 @@ matchGuard :: [TypecheckedStmt] 	-- Guard
            -> DsMatchContext            -- Context
 	   -> DsM MatchResult
 
-matchGuard (ExprStmt expr locn : should_be_null) ctx 
+-- See comments with HsExpr.Stmt re what an ExprStmt means
+-- Here we must be in a guard context (not do-expression, nor list-comp)	
+
+matchGuard [ResultStmt expr locn] ctx 
   = putSrcLocDs locn (dsExpr expr) 	`thenDs` \ core_expr ->
     returnDs (cantFailMatchResult core_expr)
 
+	-- ExprStmts must be guards
 	-- Turn an "otherwise" guard is a no-op
-matchGuard (GuardStmt (HsVar v) _ : stmts) ctx
+matchGuard (ExprStmt (HsVar v) _ _ : stmts) ctx
   |  v `hasKey` otherwiseIdKey
-  || v `hasKey` trueDataConKey
+  || v `hasKey` getUnique trueDataConId	
+	-- trueDataConId doesn't have the same 
+	-- unique as trueDataCon
   = matchGuard stmts ctx
 
-matchGuard (GuardStmt expr locn : stmts) ctx
+matchGuard (ExprStmt expr _ locn : stmts) ctx
   = matchGuard stmts ctx 		`thenDs` \ match_result ->
     putSrcLocDs locn (dsExpr expr)	`thenDs` \ pred_expr ->
     returnDs (mkGuardedMatchResult pred_expr match_result)