error: struct field shorthands are unstable (see issue #37340)
  --> /in/foo.rs:32:17
   |
32 |                 a0,
   |                 ^^

error: struct field shorthands are unstable (see issue #37340)
  --> /in/foo.rs:33:17
   |
33 |                 others
   |                 ^^^^^^

error: struct field shorthands are unstable (see issue #37340)
  --> /in/foo.rs:40:17
   |
40 |                 numerator,
   |                 ^^^^^^^^^

error: struct field shorthands are unstable (see issue #37340)
  --> /in/foo.rs:41:17
   |
41 |                 denominator
   |                 ^^^^^^^^^^^

error: aborting due to 4 previous errors