1 error: expected one of `!`, `(`, `+`, `,`, `::`, `<`, or `>`, found `=`
2 --> $DIR/trait-path-expected-token.rs:7:33
4 LL | fn f1<'a>(arg : Box<dyn X<Y = B = &'a ()>>) {}
5 | - ^ expected one of 7 possible tokens
7 | maybe try to close unmatched angle bracket
9 error: aborting due to previous error