mirror of https://github.com/rust-lang/rust.git
25 lines
822 B
Rust
25 lines
822 B
Rust
//! This test checks that we allow subtyping predicates that contain opaque types.
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//! No hidden types are being constrained in the subtyping predicate, but type and
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//! lifetime variables get subtyped in the generic parameter list of the opaque.
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//@ check-pass
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fn foo() -> impl Default + Copy {
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if false {
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let x = Default::default();
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// add `Subtype(?x, ?y)` obligation
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let y = x;
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// Make a tuple `(?x, ?y)` and equate it with `(impl Default, u32)`.
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// For us to try and prove a `Subtype(impl Default, u32)` obligation,
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// we have to instantiate both `?x` and `?y` without any
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// `select_where_possible` calls inbetween.
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let mut tup = &mut (x, y);
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let assign_tup = &mut (foo(), 1u32);
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tup = assign_tup;
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}
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1u32
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}
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fn main() {}
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