Associated Type Equality Bounds are not properly resolved

Hello!

Given the following definitions (minimized from my actual use case):

trait DeviceIdContext {
    type DeviceId;
}

trait BindingsContext<E> {}

trait EventContext<E> {
    type OtherEventRepr;
}

trait CoreContext<BC>: DeviceIdContext + EventContext<Self::DeviceId> {}

struct Foo<D> {
    d: D,
}

I'd like to be able to write the following implementation:

impl<D> Foo<D> {
    fn foo<BC, CC>(self, _core_ctx: CC, _bindings_ctx: BC)
    where 
        BC: BindingsContext<CC::OtherEventRepr>,
        CC: CoreContext<BC, DeviceId = D> {}
}

Compilation fails with error:

CC: EventContext<D> is not satisfied

However, that's incorrect. CC must implement EventContext. I've bounded its associated type DeviceId to equal D. Along with the compilation error, comes the suggestion to add an explicit EventContext<D> bound. That would look like the following:

impl<D> Foo<D> {
    fn foo<BC, CC>(self, _core_ctx: CC, _bindings_ctx: BC)
    where 
        BC: BindingsContext<CC::OtherEventRepr>,
        CC: CoreContext<BC, DeviceId = D> + EventContext<D> {}
}

That still fails to compile, this time for a different reason:

ambiguous associated type OtherEventRepr in bounds of CC
| ambiguous OtherEventRepr from EventContext<D>
| ambiguous OtherEventRepr from EventContext<<CC as DeviceIdContext>::DeviceId>

Interestingly, If I rework this implementation to be a free function, everything compiles:

fn foo<
    BC: BindingsContext<CC::OtherEventRepr>,
    CC: CoreContext<BC>
>(core_ctx: CC, bindings_ctx: BC, foo: Foo<CC::DeviceId>) {}

It seems to me that the DeviceId = D bound I've written isn't able to be reasoned about properly in examples 1 & 2. Checkout this Rust Playground with all the examples from above: https://play.rust-lang.org/?version=stable&mode=debug&edition=2024&gist=91049b46781fb054e583994d7dde5966

I observe this issue on Stable, Beta & Nightly.

Start by running the minimized examples in the linked Rust Playground, comparing the method implementation with the free-function version. Investigate why the DeviceId = D equality bound is not used to resolve EventContext<D> and why adding that bound makes OtherEventRepr ambiguous. Done means the reported method form compiles without redundant bounds or ambiguity.