Use uninit checking from rustc #10520
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r? @Alexendoo (rustbot has picked a reviewer for you, use r? to override) |
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Alexendoo
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Noratrieb
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| // edge case: For now we lint on empty arrays | ||
| let _: [u8; 0] = unsafe { MaybeUninit::uninit().assume_init() }; | ||
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| // edge case: For now we accept unit tuples |
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I also changed this comment because this isn't really a "for now", ZSTs are simply valid here.
rustc has proper heuristics for actually checking whether a type allows being left uninitialized (by asking CTFE). We can now use this for our helper instead of rolling our own bad version with false positives.
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Mar 21, 2023
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Great, thanks! @bors r+ |
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☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test |
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I believe we've found a false-positive for this here. |
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Uh, that's because this is a polymorphic type and we are conservative around polymorphic types and always say that they are wrong. |
This was referenced Mar 26, 2023
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In uninit checking, add fallback for polymorphic types After #10520, we always assumed that polymorphic types do not allow to be left uninitialized. But we can do better, by peeking into polymorphic types and adding a few special cases for going through tuples, arrays (because the length may be polymorphic) and blanket allowing all unions (like MaybeUninit). fixes #10551 changelog: [uninit_vec]: fix false positive for polymorphic types changelog: [uninit_assumed_init]: fix false positive for polymorphic types
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rustc has proper heuristics for actually checking whether a type allows being left uninitialized (by asking CTFE). We can now use this for our helper instead of rolling our own bad version with false positives.
I added this in rustc in rust-lang/rust#108669
Fix #10407
changelog: [
uninit_vec]: fix false positiveschangelog: [
uninit_assumed_init]: fix false positives