Static IMPLICIT_SYSROOT_CRATE_IMPORT 

pub static IMPLICIT_SYSROOT_CRATE_IMPORT: &Lint

The implicit_sysroot_crate_import detects use of extern crate to import non-sysroot crates (e.g. crates.io deps) from the sysroot, which is dangerous because these crates are not guaranteed to exist exactly once, and so may be missing entirely or appear multiple times resulting in ambiguity.