mirror of https://github.com/rust-lang/rust
35 lines
855 B
Rust
35 lines
855 B
Rust
// Basic test for liveness constraints: the region (`R1`) that appears
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// in the type of `p` includes the points after `&v[0]` up to (but not
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// including) the call to `use_x`. The `else` branch is not included.
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//@ check-pass
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#![allow(warnings)]
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#![feature(dropck_eyepatch)]
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fn use_x(_: usize) -> bool { true }
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fn main() {
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let mut v = [1, 2, 3];
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let p: WrapMayDangle<& /* R4 */ usize> = WrapMayDangle { value: &v[0] };
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if true {
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// `p` will get dropped at end of this block. However, because of
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// the `#[may_dangle]` attribute, we do not need to consider R4
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// live after this point.
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use_x(*p.value);
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} else {
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v[0] += 1;
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use_x(22);
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}
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v[0] += 1;
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}
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struct WrapMayDangle<T> {
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value: T
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}
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unsafe impl<#[may_dangle] T> Drop for WrapMayDangle<T> {
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fn drop(&mut self) { }
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}
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