Re: Range Check Query

[dewar@cs.nyu.edu (Robert Dewar)]

"If the compiler is smart enough [to recognize that a comparison of a value
of limited range with a constant is always False], it should probably warn .."

First, that's not an easy check to do, it certainly doesn't fall out free,
because it requires the generalized notion of the subtype of a result, where
in the language we are only ever interested in the base type for operands
of an operator. Certainly it could be done with a special check.

Second, are you really *sure* that you want this warning. Yes I know you
can suppress warnings, but the trick is to keep warnings useful so that
people don't need to suppress them in normal cases.

I an very dubious that this is a desirable approach

Robert Eachus' analysis of the original question is certainly quite
correct, there is no basis to expect range constraint to be raised
in either situation.