error[E0515]: cannot return reference to temporary value
  --> $DIR/borrowck-error.rs:7:5
   |
LL |     &HashMap::new()
   |     ^--------------
   |     ||
   |     |temporary value created here
   |     returns a reference to data owned by the current function

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0515`.