Error code E0259
The name chosen for an external crate conflicts with another external crate that has been imported into the current module.
Erroneous code example:
extern crate core;
extern crate std as core;
fn main() {}
ⓘ
The solution is to choose a different name that doesn't conflict with any external crate imported into the current module.
Correct example:
extern crate core;
extern crate std as other_name;
fn main() {}