error: extern location for foo is of an unknown type: $DIR/issue-104621-extern-bad-file.rs --> $DIR/issue-104621-extern-bad-file.rs:4:1 | LL | extern crate foo; | ^^^^^^^^^^^^^^^^^ error: file name should be lib*.rlib or lib*.so --> $DIR/issue-104621-extern-bad-file.rs:4:1 | LL | extern crate foo; | ^^^^^^^^^^^^^^^^^ error[E0463]: can't find crate for `foo` --> $DIR/issue-104621-extern-bad-file.rs:4:1 | LL | extern crate foo; | ^^^^^^^^^^^^^^^^^ can't find crate error: aborting due to 3 previous errors For more information about this error, try `rustc --explain E0463`.