1 error: `?` may only modify trait bounds, not lifetime bounds
2 --> $DIR/issue-68890-2.rs:3:15
4 LL | type X<'a> = (?'a) +;
7 error[E0224]: at least one trait is required for an object type
8 --> $DIR/issue-68890-2.rs:3:14
10 LL | type X<'a> = (?'a) +;
13 error: aborting due to 2 previous errors
15 For more information about this error, try `rustc --explain E0224`.