src/test/ui/regions/region-lifetime-bounds-on-fns-where-clause.nll.stderr

   1 error: lifetime may not live long enough
   2   --> $DIR/region-lifetime-bounds-on-fns-where-clause.rs:8:5
   3    |
   4 LL | fn b<'a, 'b>(x: &mut &'a isize, y: &mut &'b isize) {
   5    |      --  -- lifetime `'b` defined here
   6    |      |
   7    |      lifetime `'a` defined here
   8 LL |     // Illegal now because there is no `'b:'a` declaration.
   9 LL |     *x = *y;
  10    |     ^^^^^^^ assignment requires that `'b` must outlive `'a`
  11    |
  12    = help: consider adding the following bound: `'b: 'a`
  13
  14 error: lifetime may not live long enough
  15   --> $DIR/region-lifetime-bounds-on-fns-where-clause.rs:14:5
  16    |
  17 LL | fn c<'a,'b>(x: &mut &'a isize, y: &mut &'b isize) {
  18    |      -- -- lifetime `'b` defined here
  19    |      |
  20    |      lifetime `'a` defined here
  21 ...
  22 LL |     a(x, y);
  23    |     ^^^^^^^ argument requires that `'b` must outlive `'a`
  24    |
  25    = help: consider adding the following bound: `'b: 'a`
  26    = note: requirement occurs because of a mutable reference to &isize
  27    = note: mutable references are invariant over their type parameter
  28    = help: see <https://doc.rust-lang.org/nomicon/subtyping.html> for more information about variance
  29
  30 error: higher-ranked subtype error
  31   --> $DIR/region-lifetime-bounds-on-fns-where-clause.rs:20:12
  32    |
  33 LL |     let _: fn(&mut &isize, &mut &isize) = a;
  34    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  35
  36 error: higher-ranked subtype error
  37   --> $DIR/region-lifetime-bounds-on-fns-where-clause.rs:20:12
  38    |
  39 LL |     let _: fn(&mut &isize, &mut &isize) = a;
  40    |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  41
  42 error: aborting due to 4 previous errors
  43