f6c5d8d599
Add note to fix `MATCH_TYPE_ON_DIAG_ITEM` Add false negative test for `uninit_assumed_init`
42 lines
1.2 KiB
Rust
42 lines
1.2 KiB
Rust
#![allow(deprecated, invalid_value, clippy::uninit_assumed_init)]
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#![warn(clippy::mem_replace_with_uninit)]
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use std::mem;
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fn might_panic<X>(x: X) -> X {
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// in practice this would be a possibly-panicky operation
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x
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}
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fn main() {
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let mut v = vec![0i32; 4];
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// the following is UB if `might_panic` panics
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unsafe {
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let taken_v = mem::replace(&mut v, mem::uninitialized());
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let new_v = might_panic(taken_v);
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std::mem::forget(mem::replace(&mut v, new_v));
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}
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unsafe {
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let taken_v = mem::replace(&mut v, mem::MaybeUninit::uninit().assume_init());
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let new_v = might_panic(taken_v);
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std::mem::forget(mem::replace(&mut v, new_v));
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}
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unsafe {
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let taken_v = mem::replace(&mut v, mem::zeroed());
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let new_v = might_panic(taken_v);
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std::mem::forget(mem::replace(&mut v, new_v));
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}
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// this is silly but OK, because usize is a primitive type
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let mut u: usize = 42;
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let uref = &mut u;
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let taken_u = unsafe { mem::replace(uref, mem::zeroed()) };
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*uref = taken_u + 1;
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// this is still not OK, because uninit
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let taken_u = unsafe { mem::replace(uref, mem::uninitialized()) };
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*uref = taken_u + 1;
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}
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