src/test/ui/issues/issue-81584.stderr

   1 error[E0515]: cannot return value referencing function parameter `y`
   2   --> $DIR/issue-81584.rs:5:22
   3    |
   4 LL |             .map(|y| y.iter().map(|x| x + 1))
   5    |                      --------^^^^^^^^^^^^^^^
   6    |                      |
   7    |                      returns a value referencing data owned by the current function
   8    |                      `y` is borrowed here
   9    |
  10    = help: use `.collect()` to allocate the iterator
  11
  12 error: aborting due to previous error
  13
  14 For more information about this error, try `rustc --explain E0515`.