1error[E0259]: the name `core` is defined multiple times 2 --> $DIR/weak-lang-item.rs:9:1 3 | 4LL | extern crate core; 5 | ^^^^^^^^^^^^^^^^^^ `core` reimported here 6 | 7 = note: `core` must be defined only once in the type namespace of this module 8help: you can use `as` to change the binding name of the import 9 | 10LL | extern crate core as other_core; 11 | 12 13error: language item required, but not found: `eh_personality` 14 15error: `#[panic_handler]` function required, but not found 16 17error: aborting due to 3 previous errors 18 19For more information about this error, try `rustc --explain E0259`. 20