1 error[E0283]: type annotations needed
2 --> $DIR/issue-21974.rs:11:19
4 LL | where &'a T : Foo,
5 | ^^^ cannot infer type for reference `&'a T`
7 = note: cannot satisfy `&'a T: Foo`
9 error: aborting due to previous error
11 For more information about this error, try `rustc --explain E0283`.