1 error[E0128]: type parameters with a default cannot use forward declared identifiers
2 --> $DIR/issue-26812.rs:13:10
4 LL | fn avg<T=T::Item>(_: T) {}
5 | ^^^^^^^ defaulted type parameters cannot be forward declared
7 error: aborting due to previous error
9 For more information about this error, try `rustc --explain E0128`.