[racket] TR error message

On Sep 22, 2010, at 8:08 AM, Sam Tobin-Hochstadt wrote:

> Here I want to reiterate something that Vincent said, which is that
> all of these clauses are just part of the type system, not the
> optimizer.  They enable the type system to know more things about the
> arguments, and when the type system knows more, the optimizer can do
> better.  But this is just the type system, and as Vincent's example
> showed up-thread, you can write a program that depends for
> type-correctness on any one of these clauses.


While this is true on the surface, it is also true that 
one could get away with a significantly simpler type for < 
if one wouldn't to exploit this information somewhere. 
Since the only place where we really exploit it for now
is the optimizer, I think it is fair that to implicitly 
equate the two. 

Of course, that does not mean the error message should 
mention this application. One day we may have another one.