mirror of https://github.com/rust-lang/rust
55 lines
2.3 KiB
Plaintext
55 lines
2.3 KiB
Plaintext
error[E0391]: cycle detected when computing type of `Foo::T`
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--> $DIR/issue-34373.rs:7:30
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LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
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| ^^^^^^^^^^
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note: ...which requires expanding type alias `DefaultFoo`...
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--> $DIR/issue-34373.rs:10:19
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LL | type DefaultFoo = Foo;
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| ^^^
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= note: ...which again requires computing type of `Foo::T`, completing the cycle
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note: cycle used when checking that `Foo` is well-formed
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--> $DIR/issue-34373.rs:7:1
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LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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= note: see https://rustc-dev-guide.rust-lang.org/overview.html#queries and https://rustc-dev-guide.rust-lang.org/query.html for more information
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error[E0038]: the trait `Trait` cannot be made into an object
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--> $DIR/issue-34373.rs:7:24
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LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
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| ^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object
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note: for a trait to be "object safe" it needs to allow building a vtable to allow the call to be resolvable dynamically; for more information visit <https://doc.rust-lang.org/reference/items/traits.html#object-safety>
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--> $DIR/issue-34373.rs:4:8
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LL | trait Trait<T> {
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| ----- this trait cannot be made into an object...
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LL | fn foo(_: T) {}
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| ^^^ ...because associated function `foo` has no `self` parameter
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help: consider turning `foo` into a method by giving it a `&self` argument
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LL | fn foo(&self, _: T) {}
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| ++++++
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help: alternatively, consider constraining `foo` so it does not apply to trait objects
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LL | fn foo(_: T) where Self: Sized {}
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| +++++++++++++++++
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error[E0392]: type parameter `T` is never used
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--> $DIR/issue-34373.rs:7:16
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LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>;
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| ^^^^^^^^^^^^^^^^^^^^^^^^^^ unused type parameter
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= help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData`
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= help: if you intended `T` to be a const parameter, use `const T: /* Type */` instead
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error: aborting due to 3 previous errors
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Some errors have detailed explanations: E0038, E0391, E0392.
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For more information about an error, try `rustc --explain E0038`.
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