error: expected one of `,` or `|`, found `&`
  --> $DIR/issue-66706.rs:2:16
   |
LL |     [0; [|_: _ &_| ()].len()]
   |               -^ expected one of `,` or `|`
   |               |
   |               help: missing `,`

error: expected identifier, found reserved identifier `_`
  --> $DIR/issue-66706.rs:8:20
   |
LL |     [0; [|f @ &ref _| {} ; 0 ].len() ];
   |                    ^ expected identifier, found reserved identifier

error: expected one of `,` or `|`, found `&`
  --> $DIR/issue-66706.rs:13:17
   |
LL |     [0; [|&_: _ &_| {}; 0 ].len()]
   |                -^ expected one of `,` or `|`
   |                |
   |                help: missing `,`

error: expected identifier, found reserved identifier `_`
  --> $DIR/issue-66706.rs:19:26
   |
LL |     [0; match [|f @ &ref _| () ] {} ]
   |         -----            ^ expected identifier, found reserved identifier
   |         |
   |         while parsing this `match` expression

error[E0282]: type annotations needed
  --> $DIR/issue-66706.rs:2:11
   |
LL |     [0; [|_: _ &_| ()].len()]
   |           ^ cannot infer type

error[E0282]: type annotations needed
  --> $DIR/issue-66706.rs:13:11
   |
LL |     [0; [|&_: _ &_| {}; 0 ].len()]
   |           ^^^^^ cannot infer type

error: aborting due to 6 previous errors

For more information about this error, try `rustc --explain E0282`.