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# 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() {}