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+An associated type wasn't specified for a trait object.
+
+Erroneous code example:
+
+```compile_fail,E0191
+trait Trait {
+    type Bar;
+}
+
+type Foo = Trait; // error: the value of the associated type `Bar` (from
+                  //        the trait `Trait`) must be specified
+```
+
+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!
+```