The logic of Message internals

Question

I am trying to figure out the logic of Message behavior.

Consider evaluation of the following:

On[]
Sin[1,1]

After eva

Answer 1

It seems that I have found one way to achieve with built-in function Message what I want:

Unprotect[Message];
Message[_, HoldForm[Block[List[$MyMagicalTag$, ___], _]], _] := Null;
Message[args___] /; 
   Block[{$MyMagicalTag$, Message}, Not@TrueQ[inMsg]] := 
  Block[{$MyMagicalTag$, inMsg = True, lastargs = HoldComplete[args]},
    Message[args]];
Message[args___] /; 
   Block[{$MyMagicalTag$, 
     Message}, (inMsg && (HoldComplete[args] =!= lastargs))] := Null;
Protect[Message];

Now things work as expected:

In[6]:= On[]
In[7]:= Sin[1,1]//AbsoluteTiming
During evaluation of In[7]:= Message::trace: Message[Sin::argx,Sin,2] --> Block[{$MyMagicalTag$,inMsg=True,lastargs=HoldComplete[Sin::argx,Sin,2]},Message[Sin::argx,Sin,2]]. >>
During evaluation of In[7]:= Sin::argx: Sin called with 2 arguments; 1 argument is expected. >>
During evaluation of In[7]:= AbsoluteTiming::trace: AbsoluteTiming[Sin[1,1]] --> {0.1502160,Sin[1,1]}. >>
Out[7]= {0.1502160,Sin[1,1]}

The only problem with the above is that CPU load is still high as you can see from the timings.

Other tested cases also work correctly:

In[8]:= 1+1//AbsoluteTiming
During evaluation of In[8]:= Plus::trace: 1+1 --> 2. >>
During evaluation of In[8]:= AbsoluteTiming::trace: AbsoluteTiming[1+1] --> {0.0400576,2}. >>
Out[8]= {0.0400576,2}

Thanks to Mr.Wizard for his help.