| error[E0391]: cycle detected when computing type of `Foo::T` |
| --> $DIR/issue-34373.rs:7:30 |
| | |
| LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>; |
| | ^^^^^^^^^^ |
| | |
| note: ...which requires expanding type alias `DefaultFoo`... |
| --> $DIR/issue-34373.rs:10:19 |
| | |
| LL | type DefaultFoo = Foo; |
| | ^^^ |
| = note: ...which again requires computing type of `Foo::T`, completing the cycle |
| note: cycle used when collecting item types in top-level module |
| --> $DIR/issue-34373.rs:1:1 |
| | |
| LL | / #![allow(warnings)] |
| LL | | |
| LL | | trait Trait<T> { |
| LL | | fn foo(_: T) {} |
| ... | |
| LL | | fn main() { |
| LL | | } |
| | |_^ |
| = 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 |
| |
| error[E0038]: the trait `Trait` cannot be made into an object |
| --> $DIR/issue-34373.rs:7:24 |
| | |
| LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>; |
| | ^^^^^^^^^^^^^^^^^ `Trait` cannot be made into an object |
| | |
| 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> |
| --> $DIR/issue-34373.rs:4:8 |
| | |
| LL | trait Trait<T> { |
| | ----- this trait cannot be made into an object... |
| LL | fn foo(_: T) {} |
| | ^^^ ...because associated function `foo` has no `self` parameter |
| help: consider turning `foo` into a method by giving it a `&self` argument |
| | |
| LL | fn foo(&self, _: T) {} |
| | ++++++ |
| help: alternatively, consider constraining `foo` so it does not apply to trait objects |
| | |
| LL | fn foo(_: T) where Self: Sized {} |
| | +++++++++++++++++ |
| |
| error[E0392]: parameter `T` is never used |
| --> $DIR/issue-34373.rs:7:16 |
| | |
| LL | pub struct Foo<T = Box<Trait<DefaultFoo>>>; |
| | ^^^^^^^^^^^^^^^^^^^^^^^^^^ unused parameter |
| | |
| = help: consider removing `T`, referring to it in a field, or using a marker such as `PhantomData` |
| = help: if you intended `T` to be a const parameter, use `const T: usize` instead |
| |
| error: aborting due to 3 previous errors |
| |
| Some errors have detailed explanations: E0038, E0391, E0392. |
| For more information about an error, try `rustc --explain E0038`. |
