error[E0223]: ambiguous associated type
  --> $DIR/E0223.rs:8:14
   |
LL |     let foo: MyTrait::X;
   |              ^^^^^^^^^^
   |
help: use fully-qualified syntax
   |
LL -     let foo: MyTrait::X;
LL +     let foo: <MyStruct as MyTrait>::X;
   |

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0223`.