[project @ 2006-01-18 12:15:37 by simonpj]

Expunge all mention of CCallable/CReturnable

ghc/compiler/deSugar/DsCCall.lhs

@@ -196,7 +196,6 @@ unboxArg arg
     maybeToBool maybe_arg3_tycon &&
     (arg3_tycon ==  byteArrayPrimTyCon ||
      arg3_tycon ==  mutableByteArrayPrimTyCon)
-    -- and, of course, it is an instance of CCallable
   = newSysLocalDs arg_ty		`thenDs` \ case_bndr ->
     newSysLocalsDs data_con_arg_tys	`thenDs` \ vars@[l_var, r_var, arr_cts_var] ->
     returnDs (Var arr_cts_var,

ghc/compiler/prelude/PrelInfo.lhs

@@ -15,7 +15,7 @@ module PrelInfo (
 	maybeCharLikeCon, maybeIntLikeCon,
 
 	-- Class categories
-	isNoDictClass, isNumericClass, isStandardClass
+	isNumericClass, isStandardClass
 
     ) where
 
@@ -23,8 +23,7 @@ module PrelInfo (
 
 import PrelNames	( basicKnownKeyNames, 
 			  hasKey, charDataConKey, intDataConKey,
-			  numericClassKeys, standardClassKeys,
-			  noDictClassKeys )
+			  numericClassKeys, standardClassKeys )
 
 import PrimOp		( PrimOp, allThePrimOps, primOpOcc, primOpTag, maxPrimOpTag )
 import DataCon		( DataCon )
@@ -132,10 +131,9 @@ maybeIntLikeCon  con = con `hasKey` intDataConKey
 %************************************************************************
 
 \begin{code}
-isNoDictClass, isNumericClass, isStandardClass :: Class -> Bool
+isNumericClass, isStandardClass :: Class -> Bool
 
 isNumericClass     clas = classKey clas `is_elem` numericClassKeys
 isStandardClass    clas = classKey clas `is_elem` standardClassKeys
-isNoDictClass      clas = classKey clas `is_elem` noDictClassKeys
 is_elem = isIn "is_X_Class"
 \end{code}

ghc/compiler/prelude/PrelNames.lhs

@@ -1040,8 +1040,6 @@ standardClassKeys = derivableClassKeys ++ numericClassKeys
 		  ++ [randomClassKey, randomGenClassKey,
 		      functorClassKey, 
 		      monadClassKey, monadPlusClassKey]
-
-noDictClassKeys = [] -- ToDo: remove?
 \end{code}
 
 @derivableClassKeys@ is also used in checking \tr{deriving} constructs

ghc/compiler/typecheck/Inst.lhs

@@ -28,7 +28,6 @@ module Inst (
 	isDict, isClassDict, isMethod, 
 	isLinearInst, linearInstType, isIPDict, isInheritableInst,
 	isTyVarDict, isMethodFor, 
-	instBindingRequired,
 
 	zonkInst, zonkInsts,
 	instToId, instName,
@@ -77,7 +76,6 @@ import HscTypes	( ExternalPackageState(..) )
 import CoreFVs	( idFreeTyVars )
 import DataCon	( DataCon, dataConTyVars, dataConStupidTheta, dataConName, dataConWrapId )
 import Id	( Id, idName, idType, mkUserLocal, mkLocalId )
-import PrelInfo	( isNoDictClass )
 import Name	( Name, mkMethodOcc, getOccName, getSrcLoc, nameModule,
 		  isInternalName, setNameUnique, mkSystemVarName )
 import NameSet	( addOneToNameSet )
@@ -195,16 +193,6 @@ linearInstType :: Inst -> TcType	-- %x::t  -->  t
 linearInstType (Dict _ (IParam _ ty) _) = ty
 \end{code}
 
-Two predicates which deal with the case where class constraints don't
-necessarily result in bindings.  The first tells whether an @Inst@
-must be witnessed by an actual binding; the second tells whether an
-@Inst@ can be generalised over.
-
-\begin{code}
-instBindingRequired :: Inst -> Bool
-instBindingRequired (Dict _ (ClassP clas _) _) = not (isNoDictClass clas)
-instBindingRequired other		       = True
-\end{code}
 
 
 %************************************************************************

ghc/compiler/typecheck/TcInstDcls.lhs

@@ -179,10 +179,6 @@ tcLocalInstDecl1 :: LInstDecl Name
 	-- Type-check all the stuff before the "where"
 	--
 	-- We check for respectable instance type, and context
-	-- but only do this for non-imported instance decls.
-	-- Imported ones should have been checked already, and may indeed
-	-- contain something illegal in normal Haskell, notably
-	--	instance CCallable [Char] 
 tcLocalInstDecl1 decl@(L loc (InstDecl poly_ty binds uprags))
   =	-- Prime error recovery, set source location
     recoverM (returnM Nothing)		$
@@ -395,18 +391,6 @@ tcInstDecl2 (InstInfo { iSpec = ispec, iBinds = binds })
 		--	See Note [Inline dfuns] below
 
 	dict_rhs
-	  | null scs_and_meths
-	  = 	-- Blatant special case for CCallable, CReturnable
-		-- If the dictionary is empty then we should never
-		-- select anything from it, so we make its RHS just
-		-- emit an error message.  This in turn means that we don't
-		-- mention the constructor, which doesn't exist for CCallable, CReturnable
-		-- Hardly beautiful, but only three extra lines.
-	    nlHsApp (noLoc $ TyApp (nlHsVar rUNTIME_ERROR_ID) 
-				   [idType this_dict_id])
-		  (nlHsLit (HsStringPrim (mkFastString msg)))
-
-	  | otherwise	-- The common case
 	  = mkHsConApp dict_constr inst_tys' (map HsVar scs_and_meths)
 		-- We don't produce a binding for the dict_constr; instead we
 		-- rely on the simplifier to unfold this saturated application

ghc/compiler/typecheck/TcSimplify.lhs

@@ -31,7 +31,7 @@ import Inst		( lookupInst, LookupInstResult(..),
 			  isMethodFor, isMethod,
 			  instToId, tyVarsOfInsts,  cloneDict,
 			  ipNamesOfInsts, ipNamesOfInst, dictPred,
-			  instBindingRequired, fdPredsOfInst,
+			  fdPredsOfInst,
 			  newDictsAtLoc, tcInstClassOp,
 			  getDictClassTys, isTyVarDict, instLoc,
 			  zonkInst, tidyInsts, tidyMoreInsts,
@@ -1350,10 +1350,6 @@ data Avail
 			-- e.g. those "given" in a signature
 	  Bool		-- True <=> actually consumed (splittable IPs only)
 
-  | NoRhs 		-- Used for Insts like (CCallable f)
-			-- where no witness is required.
-			-- ToDo: remove?
-
   | Rhs 		-- Used when there is a RHS
 	(LHsExpr TcId) 	-- The RHS
 	[Inst]		-- Insts free in the RHS; we need these too
@@ -1375,7 +1371,6 @@ pprAvails avails = vcat [sep [ppr inst, nest 2 (equals <+> pprAvail avail)]
 instance Outputable Avail where
     ppr = pprAvail
 
-pprAvail NoRhs	       	= text "<no rhs>"
 pprAvail IsFree	       	= text "Free"
 pprAvail Irred	       	= text "Irred"
 pprAvail (Given x b)   	= text "Given" <+> ppr x <+> 
@@ -1409,7 +1404,6 @@ extractResults avails wanteds
 	  Nothing    -> pprTrace "Urk: extractResults" (ppr w) $
 			go avails binds irreds frees ws
 
-	  Just NoRhs  -> go avails		 binds irreds     frees     ws
 	  Just IsFree -> go (add_free avails w)  binds irreds     (w:frees) ws
 	  Just Irred  -> go (add_given avails w) binds (w:irreds) frees     ws
 
@@ -1443,11 +1437,7 @@ extractResults avails wanteds
     get_root irreds frees IsFree       w = cloneDict w	`thenM` \ w' ->
 					   returnM (irreds, w':frees, instToId w')
 
-    add_given avails w 
-	| instBindingRequired w = addToFM avails w (Given (instToId w) True)
-	| otherwise		= addToFM avails w NoRhs
-	-- NB: make sure that CCallable/CReturnable use NoRhs rather
-	--	than Given, else we end up with bogus bindings.
+    add_given avails w = addToFM avails w (Given (instToId w) True)
 
     add_free avails w | isMethod w = avails
 		      | otherwise  = add_given avails w
@@ -1828,8 +1818,7 @@ addWanted :: WantSCs -> Avails -> Inst -> LHsExpr TcId -> [Inst] -> TcM Avails
 addWanted want_scs avails wanted rhs_expr wanteds
   = addAvailAndSCs want_scs avails wanted avail
   where
-    avail | instBindingRequired wanted = Rhs rhs_expr wanteds
-	  | otherwise		       = ASSERT( null wanteds ) NoRhs
+    avail = Rhs rhs_expr wanteds
 
 addGiven :: Avails -> Inst -> TcM Avails
 addGiven avails given = addAvailAndSCs AddSCs avails given (Given (instToId given) False)
@@ -2197,9 +2186,7 @@ get_default_tys
 
 When typechecking _ccall_s, TcExpr ensures that the external
 function is only passed arguments (and in the other direction,
-results) of a restricted set of 'native' types. This is
-implemented via the help of the pseudo-type classes,
-@CReturnable@ (CR) and @CCallable@ (CC.)
+results) of a restricted set of 'native' types.
 
 The interaction between the defaulting mechanism for numeric
 values and CC & CR can be a bit puzzling to the user at times.
@@ -2218,10 +2205,6 @@ is not an instance of CR. If the default list is equal to
 Haskell 1.4's default-default of (Int, Double), 'x' has type
 Int.
 
-To try to minimise the potential for surprises here, the
-defaulting mechanism is turned off in the presence of
-CCallable and CReturnable.
-
 End of aside]