error[E0259]: the name `test_macros` is defined multiple times
  --> $DIR/shadow.rs:6:1
   |
LL | extern crate test_macros;
   | ------------------------- previous import of the extern crate `test_macros` here
LL | #[macro_use]
LL | extern crate test_macros;
   | ^^^^^^^^^^^^^^^^^^^^^^^^^ `test_macros` reimported here
   |
   = note: `test_macros` must be defined only once in the type namespace of this module

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0259`.