error: mismatched closing delimiter: `]`
  --> $DIR/issue-63116.rs:3:14
   |
LL | impl W <s(f;Y(;]
   |              ^ ^ mismatched closing delimiter
   |              |
   |              unclosed delimiter

error: this file contains an unclosed delimiter
  --> $DIR/issue-63116.rs:3:18
   |
LL | impl W <s(f;Y(;]
   |          -     -^
   |          |     |
   |          |     missing open `[` for this delimiter
   |          unclosed delimiter

error: aborting due to 2 previous errors