Walter Bright:
Well, it should for those cases.
OK, then I'll split that enhancement request into a bug report.
Yeah, it does, unless you care to put in the compiler a long list of special cases. For example, what about $+$, n+$, $+$-$+1, $<<n, etc.? These sort of turn into whack-a-mole games.
I agree that putting lot of similar special cased tests in the compiler is a bad idea (also because code like $+$-$+1 is very uncommon). But can't the already present expression range analysis be used to cover some simple but common enough bugs?
Since the bug is caught anyway, such is an extremely low priority because it's got such a low payoff.
If that's true then why aren't you programming in Python? :-) Spotting mistakes at compile time is usually better because the sooner you find bugs, the less problems they cause. And because compile-time tests work on all code paths, while run-time tests only work on the code actively run (so bugs in uncommonly run code paths sometimes do not get caught, and maybe are caught much later by a client running the code). This is one of the main advantages of static typing over unit-testing.
Bye, bearophile
