error[E0005]: refutable pattern in `for` loop binding
  --> $DIR/E0297.rs:4:9
   |
LL |     for Some(x) in xs {}
   |         ^^^^^^^ pattern `None` not covered
   |
   = note: the matched value is of type `Option<i32>`

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0005`.