error: imports can only refer to extern crate names passed with `--extern` in macros originating from 2015 edition
  --> <::edition_imports_2015::gen_gated macros>:1:50
   |
LL | (  ) => { fn check_gated (  ) { enum E { A } use E :: * ; } }
   |                                                  ^
   | 
  ::: $DIR/edition-imports-virtual-2015-gated.rs:9:5
   |
LL |     gen_gated!();
   |     ------------- not an extern crate passed with `--extern`
   |
note: this import refers to the enum defined here
  --> $DIR/edition-imports-virtual-2015-gated.rs:9:5
   |
LL |     gen_gated!();
   |     ^^^^^^^^^^^^^
   = note: this error originates in a macro outside of the current crate (in Nightly builds, run with -Z external-macro-backtrace for more info)

error: aborting due to previous error