39 lines
857 B
Rust
39 lines
857 B
Rust
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//@ known-bug: rust-lang/rust#126944
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// Step 1: Create two names for a single type: `Thing` and `AlsoThing`
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struct Thing;
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struct Dummy;
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pub trait DummyTrait {
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type DummyType;
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}
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impl DummyTrait for Dummy {
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type DummyType = Thing;
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}
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type AlsoThing = <Dummy as DummyTrait>::DummyType;
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// Step 2: Create names for a single trait object type: `TraitObject` and `AlsoTraitObject`
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pub trait SomeTrait {
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type Item;
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}
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type TraitObject = dyn SomeTrait<Item = AlsoThing>;
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type AlsoTraitObject = dyn SomeTrait<Item = Thing>;
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// Step 3: Force the compiler to check whether the two names are the same type
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pub trait Supertrait {
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type Foo;
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}
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pub trait Subtrait: Supertrait<Foo = TraitObject> {}
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pub trait HasOutput<A: ?Sized> {
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type Output;
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}
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fn foo<F>() -> F::Output
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where
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F: HasOutput<dyn Subtrait<Foo = AlsoTraitObject>>,
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{
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todo!()
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}
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