https://issues.dlang.org/show_bug.cgi?id=15585
--- Comment #3 from [email protected] --- (In reply to Andrei Alexandrescu from comment #2) > Thomas, do you have a code sample that illustrates the problem? Sorry; I linked you to this issue by accident. Issue 14835 is the blocker that I mentioned. That said... bool isValidDChar(dchar cp) { if (cp > dchar.max) return false; else return true; } The compiler automatically assumes that (cp <= dchar.max), always. So, *IF* VRP propagated to comparisons, this function would be "optimized" to always return true - which it should not, because it's quite easy to generate dchar values that are greater than dchar.max, even in valid code. However, VRP isn't currently used for compile-time evaluation of comparisons, so there is (to my knowledge) no way to trigger this issue without my VRP upgrade PR ( https://github.com/dlang/dmd/pull/5229 ). It's a non-issue; the latest version of that PR already includes the fix for this, so no-one but me should ever be bothered by it, I hope. --
