Error code E0260
The name for an item declaration conflicts with an external crate's name.
Erroneous code example:
extern crate core; struct core; fn main() {}
There are two possible solutions:
Solution #1: Rename the item.
#![allow(unused)] fn main() { extern crate core; struct xyz; }
Solution #2: Import the crate with a different name.
#![allow(unused)] fn main() { extern crate core as xyz; struct abc; }
See the Declaration Statements section of the reference for more information about what constitutes an item declaration and what does not.