error[E0599]: the method `f` exists for struct `S`, but its trait bounds were not satisfied
  --> $DIR/method-unsatisfied-assoc-type-predicate.rs:26:7
   |
LL | struct S;
   | -------- method `f` not found for this struct because it doesn't satisfy `<S as X>::Y<i32> = i32` or `S: M`
...
LL |     a.f();
   |       ^ method cannot be called on `S` due to unsatisfied trait bounds
   |
note: trait bound `<S as X>::Y<i32> = i32` was not satisfied
  --> $DIR/method-unsatisfied-assoc-type-predicate.rs:12:11
   |
LL | impl<T: X<Y<i32> = i32>> M for T {}
   |           ^^^^^^^^^^^^   -     -
   |           |
   |           unsatisfied trait bound introduced here
   = help: items from traits can only be used if the trait is implemented and in scope
note: `M` defines an item `f`, perhaps you need to implement it
  --> $DIR/method-unsatisfied-assoc-type-predicate.rs:8:1
   |
LL | trait M {
   | ^^^^^^^

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0599`.