Complete the evidence generation for GADTs

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

diff --git a/compiler/typecheck/TcType.lhs b/compiler/typecheck/TcType.lhs
index 84d944a..55e20fc 100644 (file)
--- a/compiler/typecheck/TcType.lhs
+++ b/compiler/typecheck/TcType.lhs
@@ -187,7 +187,7 @@ import PrelNames    -- Lots (e.g. in isFFIArgumentTy)
 import TysWiredIn      ( unitTyCon, charTyCon, listTyCon )
 import BasicTypes      ( IPName(..), Arity, ipNameName )
 import SrcLoc          ( SrcLoc, SrcSpan )
-import Util            ( snocView, equalLength )
+import Util            ( equalLength )
 import Maybes          ( maybeToBool, expectJust, mapCatMaybes )
 import ListSetOps      ( hasNoDups )
 import List            ( nubBy )
@@ -988,8 +988,9 @@ tcTyVarsOfTypes :: [Type] -> TyVarSet
 tcTyVarsOfTypes tys = foldr (unionVarSet.tcTyVarsOfType) emptyVarSet tys
 
 tcTyVarsOfPred :: PredType -> TyVarSet
-tcTyVarsOfPred (IParam _ ty)  = tcTyVarsOfType ty
-tcTyVarsOfPred (ClassP _ tys) = tcTyVarsOfTypes tys
+tcTyVarsOfPred (IParam _ ty)   = tcTyVarsOfType ty
+tcTyVarsOfPred (ClassP _ tys)  = tcTyVarsOfTypes tys
+tcTyVarsOfPred (EqPred ty1 ty2) = tcTyVarsOfType ty1 `unionVarSet` tcTyVarsOfType ty2
 \end{code}
 
 Note [Silly type synonym]
@@ -1026,8 +1027,9 @@ exactTyVarsOfType ty
     go (AppTy fun arg)           = go fun `unionVarSet` go arg
     go (ForAllTy tyvar ty)       = delVarSet (go ty) tyvar
 
-    go_pred (IParam _ ty)  = go ty
-    go_pred (ClassP _ tys) = exactTyVarsOfTypes tys
+    go_pred (IParam _ ty)    = go ty
+    go_pred (ClassP _ tys)   = exactTyVarsOfTypes tys
+    go_pred (EqPred ty1 ty2) = go ty1 `unionVarSet` go ty2
 
 exactTyVarsOfTypes :: [TcType] -> TyVarSet
 exactTyVarsOfTypes tys = foldr (unionVarSet . exactTyVarsOfType) emptyVarSet tys
@@ -1043,6 +1045,7 @@ tyClsNamesOfType (TyConApp tycon tys)         = unitNameSet (getName tycon) `unionNa
 tyClsNamesOfType (NoteTy _ ty2)            = tyClsNamesOfType ty2
 tyClsNamesOfType (PredTy (IParam n ty))     = tyClsNamesOfType ty
 tyClsNamesOfType (PredTy (ClassP cl tys))   = unitNameSet (getName cl) `unionNameSets` tyClsNamesOfTypes tys
+tyClsNamesOfType (PredTy (EqPred ty1 ty2))  = tyClsNamesOfType ty1 `unionNameSets` tyClsNamesOfType ty2
 tyClsNamesOfType (FunTy arg res)           = tyClsNamesOfType arg `unionNameSets` tyClsNamesOfType res
 tyClsNamesOfType (AppTy fun arg)           = tyClsNamesOfType fun `unionNameSets` tyClsNamesOfType arg
 tyClsNamesOfType (ForAllTy tyvar ty)       = tyClsNamesOfType ty