E0502E0502 — Cannot Borrow as Mutable Because Also Borrowed as Immutable
A value cannot be mutably borrowed while an immutable borrow is still active.
E0308Different match arms return incompatible types.
All arms of a match expression must return the same type. Two or more arms are returning values of different types, which Rust does not allow.
Ensure all match arms return the same type. Use an enum to wrap different types if needed. Convert values to a common type in each arm. Use Box<dyn Trait> for trait objects.
E0502A value cannot be mutably borrowed while an immutable borrow is still active.
E0658A feature that is not yet stabilized in Rust is being used without the feature gate.
E0277A type does not implement a required trait.
panic-index-out-of-boundsThe program panicked because an index was out of the valid range for a collection.
E0308The expected type does not match the actual type provided.
E0283Multiple trait implementations could apply, and Rust cannot determine which one to use.