45 lines
1.0 KiB
Rust
45 lines
1.0 KiB
Rust
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// edition:2018
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// Test that we get the expected borrow check errors when an async
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// function (which takes multiple lifetimes) only returns data from
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// one of them.
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async fn multiple_named_lifetimes<'a, 'b>(a: &'a u8, _: &'b u8) -> &'a u8 {
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a
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}
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// Both are borrowed whilst the future is live.
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async fn future_live() {
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let mut a = 22;
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let mut b = 44;
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let future = multiple_named_lifetimes(&a, &b);
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a += 1; //~ ERROR cannot assign
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b += 1; //~ ERROR cannot assign
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let p = future.await;
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drop(p);
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}
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// Just the return value is live after future is awaited.
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async fn just_return_live() {
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let mut a = 22;
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let mut b = 44;
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let future = multiple_named_lifetimes(&a, &b);
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let p = future.await;
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a += 1; //~ ERROR cannot assign
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b += 1;
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drop(p);
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}
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// Once `p` is dead, both `a` and `b` are unborrowed.
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async fn after_both_dead() {
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let mut a = 22;
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let mut b = 44;
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let future = multiple_named_lifetimes(&a, &b);
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let p = future.await;
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drop(p);
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a += 1;
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b += 1;
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}
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fn main() { }
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