1 error[E0106]: missing lifetime specifier
2 --> $DIR/issue-63388-2.rs:12:10
4 LL | foo: &dyn Foo, bar: &'a dyn Foo
7 | ^ expected named lifetime parameter
9 = help: this function's return type contains a borrowed value, but the signature does not say whether it is borrowed from `foo` or `bar`
10 help: consider using the `'a` lifetime
15 error: aborting due to previous error
17 For more information about this error, try `rustc --explain E0106`.