Complete the evidence generation for GADTs

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

diff --git a/compiler/typecheck/TcExpr.lhs b/compiler/typecheck/TcExpr.lhs
index 43360c7..bda4e2f 100644 (file)
--- a/compiler/typecheck/TcExpr.lhs
+++ b/compiler/typecheck/TcExpr.lhs
@@ -29,15 +29,15 @@ import TcUnify              ( tcInfer, tcSubExp, tcFunResTy, tcGen, boxyUnify, subFunTys, za
                          boxySplitListTy, boxySplitTyConApp, wrapFunResCoercion, preSubType,
                          unBox )
 import BasicTypes      ( Arity, isMarkedStrict )
-import Inst            ( newMethodFromName, newIPDict, mkInstCoFn,
-                         newDicts, newMethodWithGivenTy, tcInstStupidTheta )
+import Inst            ( newMethodFromName, newIPDict, instCall,
+                         newMethodWithGivenTy, instStupidTheta )
 import TcBinds         ( tcLocalBinds )
 import TcEnv           ( tcLookup, tcLookupDataCon, tcLookupField )
 import TcArrows                ( tcProc )
 import TcMatches       ( tcMatchesCase, tcMatchLambda, tcDoStmts, tcBody,
                          TcMatchCtxt(..) )
 import TcHsType                ( tcHsSigType, UserTypeCtxt(..) )
-import TcPat           ( tcOverloadedLit, badFieldCon )
+import TcPat           ( tcOverloadedLit, addDataConStupidTheta, badFieldCon )
 import TcMType         ( tcInstTyVars, newFlexiTyVarTy, newBoxyTyVars,
                          readFilledBox, zonkTcTypes )
 import TcType          ( TcType, TcSigmaType, TcRhoType, TvSubst,
@@ -489,14 +489,11 @@ tcExpr expr@(RecordUpd record_expr rbinds _ _) res_ty
        -- dictionaries for the data type context, since we are going to
        -- do pattern matching over the data cons.
        --
-       -- What dictionaries do we need?  
-       -- We just take the context of the first data constructor
-       -- This isn't right, but I just can't bear to union up all the relevant ones
+       -- What dictionaries do we need?  The tyConStupidTheta tells us.
     let
        theta' = substTheta inst_env (tyConStupidTheta tycon)
     in
-    newDicts RecordUpdOrigin theta'    `thenM` \ dicts ->
-    extendLIEs dicts                   `thenM_`
+    instStupidTheta RecordUpdOrigin theta'     `thenM_`
 
        -- Phew!
     returnM (mkHsCoerce co_fn (RecordUpd record_expr' rbinds' record_ty result_record_ty))
@@ -791,7 +788,8 @@ instFun orig fun subst tv_theta_prs
        = (map (substTyVar subst) tvs, substTheta subst theta)
 
     inst_stupid (HsVar fun_id) ((tys,_):_)
-       | Just con <- isDataConId_maybe fun_id = tcInstStupidTheta con tys
+       | Just con <- isDataConId_maybe fun_id 
+       = addDataConStupidTheta orig con tys
     inst_stupid _ _ = return ()
 
     go _ fun [] = return fun
@@ -804,9 +802,7 @@ instFun orig fun subst tv_theta_prs
                -- of newMethod: see Note [Multiple instantiation]
 
     go _ fun ((tys, theta) : prs)
-       = do { dicts <- newDicts orig theta
-            ; extendLIEs dicts
-            ; let co_fn = mkInstCoFn tys dicts
+       = do { co_fn <- instCall orig tys theta
             ; go False (HsCoerce co_fn fun) prs }
 
        --      Hack Alert (want_method_inst)!