Improve ASSERT

diff --git a/compiler/iface/TcIface.lhs b/compiler/iface/TcIface.lhs
index 83a2458..fde3146 100644 (file)
--- a/compiler/iface/TcIface.lhs
+++ b/compiler/iface/TcIface.lhs
@@ -919,7 +919,7 @@ tcIfaceAlt scrut (tycon, inst_tys) (IfaceDataAlt data_occ, arg_strs, rhs)
        ; tcIfaceDataAlt con inst_tys arg_strs rhs }
                  
 tcIfaceAlt _ (tycon, inst_tys) (IfaceTupleAlt _boxity, arg_occs, rhs)
-  = ASSERT( isTupleTyCon tycon )
+  = ASSERT2( isTupleTyCon tycon, ppr tycon )
     do { let [data_con] = tyConDataCons tycon
        ; tcIfaceDataAlt data_con inst_tys arg_occs rhs }