Make mem::uninitialized and mem::zeroed panic for (some) types where 0 is a niche

language design Unsafe Code Guidelines
2

I think this is a solid idea for two reasons:

  • It prevents LLVM from getting excited over getting to dereference a null &T speculatively.
  • It teaches people that, unlike e.g. in Go you can't just memset a pile of bits to zero and be all like "ah yes this is fine because I'm going to initialize this in five seconds". Crashes are much more instructive than your program mysteriously becoming faster because LLVM deleted your code and your lunch.
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