Trait objects need to have all associated types specified. Erroneous code example:
trait Trait { type Bar; } type Foo = Trait; // error: the value of the associated type `Bar` (from // the trait `Trait`) must be specified
Please verify you specified all associated types of the trait and that you used the right trait. Example:
trait Trait { type Bar; } type Foo = Trait<Bar=i32>; // ok!