Bug in ^^

[Vladimir Panteleev]

On Tuesday, 17 September 2019 at 19:22:44 UTC, Timon Gehr wrote:
> It's not the same. C compilers warn about overflows that are 
> UB. They don't complain about overflows that have defined 
> behavior:

I'm not so sure that's the actual distinction.

The error messages do not mention undefined behavior.

The GCC source code for this does not mention undefined behavior:

https://github.com/gcc-mirror/gcc/blob/5fe20025f581fb0c215611434d76696161d4cbd3/gcc/c-family/c-warn.c#L70

The clang source code does not mention anything about undefined 
behavior:

https://github.com/CyberShadow/llvm-project/blob/6e4932ebe9448b9bab922b225a8012669972ff0c/clang/lib/AST/ExprConstant.cpp#L2310

It seems to me that the more likely explanation is that making 
the operands unsigned is a method of squelching the warning.

> In D, all overflows in operations on basic integer types have 
> defined behavior, not just those operating on unsigned integers.

Regardless of what other languages do, or the pedantic details 
involved, it seems to me that warning on detectable overflows 
would simply be more useful for D users (provided there is a way 
to squelch the warning). Therefore, D should do it.