# Error code E0191

An associated type wasn’t specified for a trait object.

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

Run

Trait objects need to have all associated types specified. Please verify that all associated types of the trait were specified and the correct trait was used. Example:

    trait Trait {
        type Bar;
    }

    type Foo = Trait<Bar=i32>; // ok!

Run

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