41 lines
923 B
Rust
41 lines
923 B
Rust
// Test that we can derive lifetime bounds on type parameters
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// from trait inheritance.
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trait Static : 'static { }
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trait Is<'a> : 'a { }
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struct Inv<'a> {
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x: Option<&'a mut &'a isize>
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}
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fn check_bound<'a,A:'a>(x: Inv<'a>, a: A) { }
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// In all of these cases, we can derive a bound for A that is longer
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// than 'a based on the trait bound of A:
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fn foo1<'a,A:Static>(x: Inv<'a>, a: A) {
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check_bound(x, a)
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}
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fn foo2<'a,A:Static>(x: Inv<'static>, a: A) {
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check_bound(x, a)
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}
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fn foo3<'a,A:Is<'a>>(x: Inv<'a>, a: A) {
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check_bound(x, a)
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}
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// In these cases, there is no trait bound, so we cannot derive any
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// bound for A and we get an error:
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fn bar1<'a,A>(x: Inv<'a>, a: A) {
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check_bound(x, a) //~ ERROR parameter type `A` may not live long enough
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}
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fn bar2<'a,'b,A:Is<'b>>(x: Inv<'a>, y: Inv<'b>, a: A) {
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check_bound(x, a) //~ ERROR parameter type `A` may not live long enough
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}
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fn main() { }
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