Slight simplification that these vars are declared once and failure is a thunk.

Author: Simon MacMullen

src/rabbit_misc.erl

@@ -250,21 +250,23 @@ assert_args_equivalence(Orig, New, Name, Keys) ->
     ok.
 
 assert_args_equivalence1(Orig, New, Name, Key) ->
-    FailureFun = fun (Orig1, New1) ->
+    {Orig1, New1} = {table_lookup(Orig, Key), table_lookup(New, Key)},
+    FailureFun = fun () ->
                      protocol_error(precondition_failed, "inequivalent arg '~s'"
                                     "for ~s: received ~s but current is ~s",
                                     [Key, rs(Name), val(New1), val(Orig1)])
                  end,
-    case {table_lookup(Orig, Key), table_lookup(New, Key)} of
+    case {Orig1, New1} of
         {Same, Same} ->
             ok;
-        {{OrigType, OrigVal} = Orig1, {NewType, NewVal} = New1} ->
+        {{OrigType, OrigVal}, {NewType, NewVal}} ->
             case type_class(OrigType) == type_class(NewType) andalso
                  OrigVal == NewVal of
                  true  -> ok;
-                 false -> FailureFun(Orig1, New1)
+                 false -> FailureFun()
             end;
-        {Orig1, New1} -> FailureFun(Orig1, New1)
+        {_, _} ->
+            FailureFun()
     end.
 
 val(undefined) ->