Clearer error message.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/rabbit_misc.erl b/src/rabbit_misc.erl
index 3a4fb024..aacc965b 100644
--- a/src/rabbit_misc.erl
+++ b/src/rabbit_misc.erl
@@ -241,10 +241,16 @@ assert_args_equivalence1(Orig, New, Name, Key) ->
         {Orig1, New1} -> protocol_error(
                            precondition_failed,
                            "inequivalent arg '~s' for ~s:  "
-                           "required ~w, received ~w",
-                           [Key, rabbit_misc:rs(Name), New1, Orig1])
+                           "received: ~s, current: ~s",
+                           [Key, rs(Name), val(New1), val(Orig1)])
     end.
 
+val(undefined) ->
+    "none";
+
+val({Type, Value}) ->
+    lists:flatten(io_lib:format("value '~s' of type '~s'", [Value, Type])).
+
 dirty_read(ReadSpec) ->
     case mnesia:dirty_read(ReadSpec) of
         [Result] -> {ok, Result};