One of the E0599 note disappears when using specialization

[glandium]

Take the following code:

struct A {
    b: bool,
}

struct Foo;

struct B<T, U=Foo>(T, U);

impl<T: Clone> Clone for B<T> {
    fn clone(&self) -> B<T> {
        B(self.0.clone(), Foo)
    }
}

fn main() {
    let i = B(A { b: true }, Foo);
    let _j = i.clone();
}

(derived from src/test/ui/unique-pinned-nocopy.rs)

This fails to compile with:

error[E0599]: no method named `clone` found for type `B<A>` in the current scope
  --> src/main.rs:17:16
   |
7  | struct B<T, U=Foo>(T, U);
   | ------------------------- method `clone` not found for this
...
17 |     let _j = i.clone();
   |                ^^^^^
   |
   = note: the method `clone` exists but the following trait bounds were not satisfied:
           `B<A> : std::clone::Clone`
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `clone`, perhaps you need to implement it:
           candidate #1: `std::clone::Clone`

https://play.rust-lang.org/?version=nightly&mode=debug&edition=2015&gist=bf41d2dae1e36b2cb0ef6d8cae3529e4

Now, add the following:

#![feature(specialization)]

impl<T: Clone, U: Clone> Clone for B<T, U> {
    default fn clone(&self) -> B<T, U> {
        B(self.0.clone(), self.1.clone())
    }
}

and it now fails with:

error[E0599]: no method named `clone` found for type `B<A>` in the current scope
  --> src/main.rs:25:16
   |
9  | struct B<T, U=Foo>(T, U);
   | ------------------------- method `clone` not found for this
...
25 |     let _j = i.clone();
   |                ^^^^^
   |
   = help: items from traits can only be used if the trait is implemented and in scope
   = note: the following trait defines an item `clone`, perhaps you need to implement it:
           candidate #1: `std::clone::Clone`

https://play.rust-lang.org/?version=nightly&mode=debug&edition=2015&gist=76f69c7ad78d25413784e9cbfd306583

The following note disappeared, but seems like it should still be emitted:

   = note: the method `clone` exists but the following trait bounds were not satisfied:
           `B<A> : std::clone::Clone`