error[E0128]: type parameters with a default cannot use forward declared identifiers
  --> $DIR/issue-18183.rs:11:20
   |
LL | pub struct Foo<Bar=Bar>(Bar); //~ ERROR E0128
   |                    ^^^ defaulted type parameters cannot be forward declared

error: aborting due to previous error

For more information about this error, try `rustc --explain E0128`.