error: expected identifier, found keyword `return`
  --> $DIR/issue-15980.rs:8:13
   |
LL |         Err(ref e) if e.kind == io::EndOfFile {
   |                                 ------------- while parsing this struct
LL |
LL |             return
   |             ^^^^^^ expected identifier, found keyword
   |
help: escape `return` to use it as an identifier
   |
LL |             r#return
   |             ++
help: you might have meant to start a match arm after the match guard
   |
LL |         Err(ref e) if e.kind == io::EndOfFile => {
   |                                               ++

error: aborting due to 1 previous error