E0658E0658 — Unstable Feature Used
A feature that is not yet stabilized in Rust is being used without the feature gate.
E0562The impl Trait syntax is used in a position where it is not allowed.
impl Trait can only be used in function argument types and return types (since Rust 1.26). It cannot be used in let bindings, struct fields, or other positions.
Use a concrete type instead of impl Trait. Use Box<dyn Trait> for trait objects in positions where impl Trait is not allowed. Use generics with trait bounds for struct fields.
E0658A feature that is not yet stabilized in Rust is being used without the feature gate.
E0277A type does not implement a required trait.
E0503A value cannot be used while it is mutably borrowed by another variable.
E0600A unary operator is applied to a type that does not support it.
E0046Not all required methods of a trait are implemented.
E0252Two imports bring the same name into scope.