error[E0490]: a value of type `&'b ()` is borrowed for too long
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^
   |
note: the type is valid for the lifetime `'a` as defined here
  --> $DIR/E0490.rs:1:6
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |      ^^
note: but the borrow lasts for the lifetime `'b` as defined here
  --> $DIR/E0490.rs:1:10
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |          ^^

error[E0495]: cannot infer an appropriate lifetime for borrow expression due to conflicting requirements
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^
   |
note: first, the lifetime cannot outlive the lifetime `'b` as defined here...
  --> $DIR/E0490.rs:1:10
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |          ^^
note: ...so that the type `&'b ()` is not borrowed for too long
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^
note: but, the lifetime must be valid for the lifetime `'a` as defined here...
  --> $DIR/E0490.rs:1:6
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |      ^^
note: ...so that reference does not outlive borrowed content
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^

error[E0495]: cannot infer an appropriate lifetime due to conflicting requirements
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^
   |
note: first, the lifetime cannot outlive the lifetime `'b` as defined here...
  --> $DIR/E0490.rs:1:10
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |          ^^
note: ...so that the expression is assignable
  --> $DIR/E0490.rs:2:20
   |
LL |     let x: &'a _ = &y;
   |                    ^^
   = note: expected `&'a &()`
              found `&'a &'b ()`
note: but, the lifetime must be valid for the lifetime `'a` as defined here...
  --> $DIR/E0490.rs:1:6
   |
LL | fn f<'a, 'b>(y: &'b ()) {
   |      ^^
note: ...so that the reference type `&'a &()` does not outlive the data it points at
  --> $DIR/E0490.rs:2:12
   |
LL |     let x: &'a _ = &y;
   |            ^^^^^

error: aborting due to 3 previous errors

For more information about this error, try `rustc --explain E0495`.