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32 lines
709 B
Rust
32 lines
709 B
Rust
//@ check-fail
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//
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// issue: <https://github.com/rust-lang/rust/issues/120217>
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#![feature(arbitrary_self_types)]
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trait Static<'a> {
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fn proof(self: *const Self, s: &'a str) -> &'static str;
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}
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fn bad_cast<'a>(x: *const dyn Static<'static>) -> *const dyn Static<'a> {
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x as _ //~ error: lifetime may not live long enough
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}
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impl Static<'static> for () {
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fn proof(self: *const Self, s: &'static str) -> &'static str {
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s
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}
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}
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fn extend_lifetime(s: &str) -> &'static str {
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bad_cast(&()).proof(s)
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}
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fn main() {
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let s = String::from("Hello World");
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let slice = extend_lifetime(&s);
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println!("Now it exists: {slice}");
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drop(s);
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println!("Now it’s gone: {slice}");
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}
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