From: simonpj@microsoft.com <unknown>
Date: Sat, 27 Oct 2007 15:54:33 +0000 (+0000)
Subject: An implication constraint can abstract over EqInsts
X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=commitdiff_plain;h=0c11d889934ea6e5311f38f5d142aff9e22abb7f

An implication constraint can abstract over EqInsts
---

diff --git a/compiler/typecheck/Inst.lhs b/compiler/typecheck/Inst.lhs
index 66e72e4..fac10ab 100644
--- a/compiler/typecheck/Inst.lhs
+++ b/compiler/typecheck/Inst.lhs
@@ -141,7 +141,7 @@ instType imp@(ImplicInst {})      = mkImplicTy (tci_tyvars imp) (tci_given imp)
 instType (EqInst {tci_left = ty1, tci_right = ty2}) = mkPredTy (EqPred ty1 ty2)
 
 mkImplicTy tvs givens wanteds	-- The type of an implication constraint
-  = ASSERT( all isDict givens )
+  = ASSERT( all isAbstractableInst givens )
     -- pprTrace "mkImplicTy" (ppr givens) $
     -- See [Equational Constraints in Implication Constraints]
     let dict_wanteds = filter (not . isEqInst) wanteds
diff --git a/compiler/typecheck/TcRnTypes.lhs b/compiler/typecheck/TcRnTypes.lhs
index 50199a7..9ecb943 100644
--- a/compiler/typecheck/TcRnTypes.lhs
+++ b/compiler/typecheck/TcRnTypes.lhs
@@ -661,7 +661,7 @@ data Inst
 				    -- Includes coercion variables
 				    --   mentioned in tci_reft
 	tci_reft   :: Refinement,
-	tci_given  :: [Inst],	    -- Only Dicts
+	tci_given  :: [Inst],	    -- Only Dicts and EqInsts
 				    --   (no Methods, LitInsts, ImplicInsts)
 	tci_wanted :: [Inst],	    -- Only Dicts and ImplicInsts
 				    --   (no Methods or LitInsts)