X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2FdeSugar%2FDsBinds.lhs;h=39e7e298abaf37d70c8e25fdaac2198e3fc95493;hp=65cb8157daaef65e72e26a0e92b9ac83f1628106;hb=777b8c4bd6f8a76f2fd365aa43451b7af098e9ef;hpb=5c4a4c4bfe2a007f41f42ebab689bcd7219bed0d

diff --git a/compiler/deSugar/DsBinds.lhs b/compiler/deSugar/DsBinds.lhs
index 65cb815..39e7e29 100644
--- a/compiler/deSugar/DsBinds.lhs
+++ b/compiler/deSugar/DsBinds.lhs
@@ -493,6 +493,15 @@ dsSpec :: Maybe CoreExpr  	-- Just rhs => RULE is for a local binding
        -> Located TcSpecPrag
        -> DsM (Maybe (OrdList (Id,CoreExpr), CoreRule))
 dsSpec mb_poly_rhs (L loc (SpecPrag poly_id spec_co spec_inl))
+  | isJust (isClassOpId_maybe poly_id)
+  = putSrcSpanDs loc $ 
+    do { warnDs (ptext (sLit "Ignoring useless SPECIALISE pragma for class method selector") 
+                 <+> quotes (ppr poly_id))
+       ; return Nothing  }  -- There is no point in trying to specialise a class op
+       	 		    -- Moreover, classops don't (currently) have an inl_sat arity set
+			    -- (it would be Just 0) and that in turn makes makeCorePair bleat
+
+  | otherwise
   = putSrcSpanDs loc $ 
     do { let poly_name = idName poly_id
        ; spec_name <- newLocalName poly_name