error[E0191]: the value of the associated type `Bar` (from the trait `Trait`) must be specified
  --> $DIR/E0191.rs:15:12
   |
LL | type Foo = Trait; //~ ERROR E0191
   |            ^^^^^ missing associated type `Bar` value

error: aborting due to previous error

If you want more information on this error, try using "rustc --explain E0191"