error: expected identifier, found keyword `extern`
  --> $DIR/keyword-extern-as-identifier-pat.rs:2:9
   |
LL |     let extern = 0;
   |         ^^^^^^ expected identifier, found keyword
   |
help: escape `extern` to use it as an identifier
   |
LL |     let r#extern = 0;
   |         ++

error: aborting due to previous error