error[E0220]: associated type `Assoc` not found for `V`
  --> $DIR/not_well_formed.rs:20:32
   |
LL | existential type Foo<V>: Trait<V::Assoc>; //~ associated type `Assoc` not found for `V`
   |                                ^^^^^^^^ associated type `Assoc` not found

error: aborting due to previous error

For more information about this error, try `rustc --explain E0220`.