error[E0311]: the parameter type `T` may not live long enough
  --> $DIR/E0311.rs:6:5
   |
LL | fn no_restriction<T>(x: &()) -> &() {
   |                         --- the parameter type `T` must be valid for the anonymous lifetime defined here...
LL |     with_restriction::<T>(x)
   |     ^^^^^^^^^^^^^^^^^^^^^ ...so that the type `T` will meet its required lifetime bounds
   |
help: consider adding an explicit lifetime bound
   |
LL | fn no_restriction<'a, T: 'a>(x: &'a ()) -> &'a () {
   |                   +++  ++++      ++         ++

error: aborting due to previous error

For more information about this error, try `rustc --explain E0311`.