1 error: expected parameter name, found `?`
2 --> $DIR/issue-84148-1.rs:1:14
5 | ^ expected parameter name
7 error: expected one of `(`, `)`, `+`, `,`, `::`, or `<`, found `?`
8 --> $DIR/issue-84148-1.rs:1:14
13 | expected one of `(`, `)`, `+`, `,`, `::`, or `<`
16 error: expected one of `->`, `where`, or `{`, found `<eof>`
17 --> $DIR/issue-84148-1.rs:1:15
20 | ^ expected one of `->`, `where`, or `{`
22 error: aborting due to 3 previous errors