mirror of https://github.com/rust-lang/rust
27 lines
810 B
Rust
27 lines
810 B
Rust
// Test that a type which is covariant with respect to its region
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// parameter yields an error when used in a contravariant way.
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//
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// Note: see variance-regions-*.rs for the tests that check that the
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// variance inference works in the first place.
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use std::marker;
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struct Covariant<'a> {
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marker: marker::PhantomData<fn(&'a ())>
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}
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fn use_<'short,'long>(c: Covariant<'long>,
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s: &'short isize,
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l: &'long isize,
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_where:Option<&'short &'long ()>) {
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// Test whether Covariant<'long> <: Covariant<'short>. Since
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// 'short <= 'long, this would be true if the Covariant type were
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// contravariant with respect to its parameter 'a.
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let _: Covariant<'short> = c;
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//~^ ERROR lifetime may not live long enough
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}
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fn main() {}
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