mirror of https://github.com/rust-lang/rust
34 lines
877 B
Rust
34 lines
877 B
Rust
#![deny(single_use_lifetimes)]
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#![allow(dead_code)]
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#![allow(unused_variables)]
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// Test that we DO warn when lifetime name is used only
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// once in a fn argument.
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fn a<'a>(x: &'a u32) { //~ ERROR `'a` only used once
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//~^ HELP elide the single-use lifetime
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}
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struct Single<'a> { x: &'a u32 }
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struct Double<'a, 'b> { f: &'a &'b u32 }
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fn center<'m>(_: Single<'m>) {} //~ ERROR `'m` only used once
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//~^ HELP elide the single-use lifetime
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fn left<'x, 'y>(foo: Double<'x, 'y>) -> &'x u32 { foo.f } //~ ERROR `'y` only used once
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//~^ HELP elide the single-use lifetime
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fn right<'x, 'y>(foo: Double<'x, 'y>) -> &'y u32 { foo.f } //~ ERROR `'x` only used once
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//~^ HELP elide the single-use lifetime
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pub trait Tfv<'a> {}
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// Do NOT lint in an HRTB.
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pub fn g<T: for<'a> Tfv<'a>>() {}
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// Do NOT lint for trait bounds.
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pub fn h<'a, S>(_: S)
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where
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S: Tfv<'a>,
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{}
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fn main() {}
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