X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2Ftypecheck%2FTcInteract.lhs;h=fb6929ae45d41b935355b4b4646e3e60a709f432;hb=1cf00bfef1c35b89c21d1eaa9f6be7354a40f016;hp=4a049aa3eee6ab0233f7c5a3a674897d85286c0a;hpb=5cfe9e92a92201043d5dbb1c4e10fef0ed0d9f49;p=ghc-hetmet.git

diff --git a/compiler/typecheck/TcInteract.lhs b/compiler/typecheck/TcInteract.lhs
index 4a049aa..fb6929a 100644
--- a/compiler/typecheck/TcInteract.lhs
+++ b/compiler/typecheck/TcInteract.lhs
@@ -1049,9 +1049,16 @@ doInteractWithInert (CIPCan { cc_id = id1, cc_flavor = ifl, cc_ip_nm = nm1, cc_i
   | nm1 == nm2
   =  	-- See Note [When improvement happens]
     do { co_var <- newCoVar ty2 ty1 -- See Note [Efficient Orientation]
-       ; let flav = Wanted (combineCtLoc ifl wfl) 
-       ; cans <- mkCanonical flav co_var 
-       ; mkIRContinue "IP/IP fundep" workItem KeepInert cans }
+       ; let flav = Wanted (combineCtLoc ifl wfl)
+       ; cans <- mkCanonical flav co_var
+       ; case wfl of
+           Given   {} -> pprPanic "Unexpected given IP" (ppr workItem)
+           Derived {} -> pprPanic "Unexpected derived IP" (ppr workItem)
+           Wanted  {} ->
+               do { setIPBind (cc_id workItem) $
+                    EvCast id1 (mkSymCoercion (mkCoVarCoercion co_var))
+                  ; mkIRStopK "IP/IP interaction (solved)" cans }
+       }
 
 -- Never rewrite a given with a wanted equality, and a type function
 -- equality can never rewrite an equality. We rewrite LHS *and* RHS