error[E0405]: cannot find trait `Foo` in this scope
  --> $DIR/avoid-getting-associated-items-of-undefined-trait.rs:8:22
   |
LL |     let _: dyn Tr + ?Foo<Assoc = ()>;
   |                      ^^^ not found in this scope

error: relaxed bounds are not permitted in trait object types
  --> $DIR/avoid-getting-associated-items-of-undefined-trait.rs:8:21
   |
LL |     let _: dyn Tr + ?Foo<Assoc = ()>;
   |                     ^^^^^^^^^^^^^^^^

error: aborting due to 2 previous errors

For more information about this error, try `rustc --explain E0405`.