error: expected identifier, found keyword `extern`
  --> $DIR/keyword-extern-as-identifier-use.rs:1:5
   |
LL | use extern::foo;
   |     ^^^^^^ expected identifier, found keyword
   |
help: you can escape reserved keywords to use them as identifiers
   |
LL | use r#extern::foo;
   |     ^^^^^^^^

error: aborting due to previous error