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Comment by dzaima | Hacker News Reader

> it's still a counterexample for "you can't define it because it means sanitizers can't warn for it"

Sure, technically you can write a sanitizer for anything. It just becomes less a "sanitizer" you can always recommend everyone everywhere use, and more of just a heuristic thing that only really works if you design your code for its arbitrary desires.

> and in the cases where it actually is intentional you can suppress the check.

imo it'd be nice to have separate types for wrapping and non-wrapping integers for that, so that you have actual language-level semantics and an easy way to mix things (e.g. wrapping arith for hashing, mixed with non-wrapping arith for loop index or whatever) instead of suppressions.

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> It just becomes less a "sanitizer" you can always recommend everyone everywhere use, and more of just a heuristic thing that only really works if you design your code for its arbitrary desires.

Sure, and that's basically what I was wondering about with respect to "can't define it" being shorthand for something else

> imo it'd be nice to have separate types for wrapping and non-wrapping integers for that

I think I'd agree, though I'd imagine it's a bit late for such things to be deeply integrated into the language. At least making your own isn't horrendously difficult.

> Sure, and that's basically what I was wondering about with respect to "can't define it" being shorthand for something else

Eh, I'd say it's still the same thing; can't define a sanitizer for it if what you define isn't a sanitizer. Depends on a specific definition of "sanitizer" though.

> At least making your own isn't horrendously difficult.

In C++ perhaps, but impossible in C. (and there are still some funky edge-cases where multiplying two `uint16_t`s can overflow due to implicit promotion to signed int; C's _BitInt solves at least that)

Clang does actually have experimental support for these - https://clang.llvm.org/docs/OverflowBehaviorTypes.html

> Depends on a specific definition of "sanitizer" though.

Hrm, I suppose a general definition would be something that you use to check for certain (unintended?) runtime behaviors? Though I also feel that could include hardened implementations and stuff like valgrind....

> In C++ perhaps, but impossible in C.

Oh, true I forgot about that.

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