Keyboard shortcuts

Press or to navigate between chapters

Press S or / to search in the book

Press ? to show this help

Press Esc to hide this help

Error code E0254

Attempt was made to import an item whereas an extern crate with this name has already been imported.

Erroneous code example:

extern crate core; mod foo { pub trait core { fn do_something(); } } use foo::core; // error: an extern crate named `core` has already // been imported in this module fn main() {}

To fix this issue, you have to rename at least one of the two imports. Example:

extern crate core as libcore; // ok! mod foo { pub trait core { fn do_something(); } } use foo::core; fn main() {}