X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Ftypecheck%2FInst.lhs;h=1032f91c60acd8f85bd7623b3f3abc9243fdcffe;hp=8d21d1bcb190b8973b99d40035e75f5c8e8a7b94;hb=6a05ec5ef5373f61b7f9f5bdc344483417fa801b;hpb=7fc749a43b4b6b85d234fa95d4928648259584f4

diff --git a/compiler/typecheck/Inst.lhs b/compiler/typecheck/Inst.lhs
index 8d21d1b..1032f91 100644
--- a/compiler/typecheck/Inst.lhs
+++ b/compiler/typecheck/Inst.lhs
@@ -42,13 +42,14 @@ module Inst (
 	isTyVarDict, isMethodFor, 
 
 	zonkInst, zonkInsts,
-	instToId, instToVar, instType, instName,
+	instToId, instToVar, instType, instName, instToDictBind,
+	addInstToDictBind,
 
 	InstOrigin(..), InstLoc, pprInstLoc,
 
 	mkWantedCo, mkGivenCo,
 	fromWantedCo, fromGivenCo,
-	eitherEqInst, mkEqInst, mkEqInsts,
+	eitherEqInst, mkEqInst, mkEqInsts, mkWantedEqInst,
 	finalizeEqInst, writeWantedCoercion,
 	eqInstType, updateEqInstCoercion,
 	eqInstCoercion,
@@ -91,6 +92,7 @@ import PrelNames
 import BasicTypes
 import SrcLoc
 import DynFlags
+import Bag
 import Maybes
 import Util
 import Outputable
@@ -205,6 +207,15 @@ tyVarsOfInst (EqInst {tci_left = ty1, tci_right = ty2}) = tyVarsOfType ty1 `unio
 
 tyVarsOfInsts insts = foldr (unionVarSet . tyVarsOfInst) emptyVarSet insts
 tyVarsOfLIE   lie   = tyVarsOfInsts (lieToList lie)
+
+
+--------------------------
+instToDictBind :: Inst -> LHsExpr TcId -> TcDictBinds
+instToDictBind inst rhs 
+  = unitBag (L (instSpan inst) (VarBind (instToId inst) rhs))
+
+addInstToDictBind :: TcDictBinds -> Inst -> LHsExpr TcId -> TcDictBinds
+addInstToDictBind binds inst rhs = binds `unionBags` instToDictBind inst rhs
 \end{code}
 
 Predicates
@@ -765,7 +776,7 @@ lookupSimpleInst (Method {tci_oid = id, tci_tys = tys, tci_theta = theta, tci_lo
 -- [Same shortcut as in newOverloadedLit, but we
 --  may have done some unification by now] 		
 
-lookupSimpleInst (LitInst {tci_lit = HsIntegral i from_integer_name, tci_ty = ty, tci_loc = loc})
+lookupSimpleInst (LitInst {tci_lit = HsIntegral i from_integer_name _, tci_ty = ty, tci_loc = loc})
   | Just expr <- shortCutIntLit i ty
   = returnM (GenInst [] (noLoc expr))
   | otherwise
@@ -777,7 +788,7 @@ lookupSimpleInst (LitInst {tci_lit = HsIntegral i from_integer_name, tci_ty = ty
 		     (mkHsApp (L (instLocSpan loc)
 			   	 (HsVar (instToId method_inst))) integer_lit))
 
-lookupSimpleInst (LitInst {tci_lit = HsFractional f from_rat_name, tci_ty = ty, tci_loc = loc})
+lookupSimpleInst (LitInst {tci_lit = HsFractional f from_rat_name _, tci_ty = ty, tci_loc = loc})
   | Just expr <- shortCutFracLit f ty
   = returnM (GenInst [] (noLoc expr))
 
@@ -789,7 +800,7 @@ lookupSimpleInst (LitInst {tci_lit = HsFractional f from_rat_name, tci_ty = ty,
     returnM (GenInst [method_inst] (mkHsApp (L (instLocSpan loc) 
 					       (HsVar (instToId method_inst))) rat_lit))
 
-lookupSimpleInst (LitInst {tci_lit = HsIsString s from_string_name, tci_ty = ty, tci_loc = loc})
+lookupSimpleInst (LitInst {tci_lit = HsIsString s from_string_name _, tci_ty = ty, tci_loc = loc})
   | Just expr <- shortCutStringLit s ty
   = returnM (GenInst [] (noLoc expr))
   | otherwise
@@ -979,11 +990,10 @@ fromWantedCo :: String -> Either TcTyVar Coercion -> TcTyVar
 fromWantedCo _ (Left covar) = covar
 fromWantedCo msg _	    = panic ("fromWantedCo: not a wanted coercion: " ++ msg)
 
-eitherEqInst 
-	:: Inst 		-- given or wanted EqInst
-	-> (TcTyVar  -> a) 	-- 	result if wanted
-	-> (Coercion -> a) 	--	result if given
-	-> a		
+eitherEqInst :: Inst 	            -- given or wanted EqInst
+	     -> (TcTyVar  -> a)     -- 	result if wanted
+	     -> (Coercion -> a)     --	result if given
+	     -> a		
 eitherEqInst (EqInst {tci_co = either_co}) withWanted withGiven
 	= case either_co of
 		Left  covar -> withWanted covar
@@ -1004,6 +1014,12 @@ mkEqInst (EqPred ty1 ty2) co
 	     }
 	where mkName uniq src_span = mkInternalName uniq (mkVarOcc "co") src_span
 
+mkWantedEqInst :: PredType -> TcM Inst
+mkWantedEqInst pred@(EqPred ty1 ty2)
+  = do { cotv <- newMetaCoVar ty1 ty2
+       ; mkEqInst pred (Left cotv)
+       }
+
 -- type inference:
 --	We want to promote the wanted EqInst to a given EqInst
 --	in the signature context.