Associated consts in traits interact weirdly with type inference

[GoldsteinE]

I tried this code (playground):

use std::marker::PhantomData;

struct IsSend<T>(PhantomData<T>);
struct TaggedBool<T>(bool, PhantomData<T>);

trait Helper<T> {
    const VALUE: TaggedBool<T>;
}

impl<T, U> Helper<T> for U {
    const VALUE: TaggedBool<T> = TaggedBool(false, PhantomData);
}

impl<T: Send> IsSend<T> {
    const VALUE: TaggedBool<T> = TaggedBool(true, PhantomData);
}

impl<T> IsSend<T> {
    const fn new(_: &T) -> Self {
        Self(PhantomData)
    }
}

const IS_SEND_PTR: bool = {
    // Some value we want to check
    let to_check: *const () = &();
    let mut _checker = IsSend::new(&to_check);
    let tb = IsSend::VALUE;
    // this works:
    // let tb = IsSend::<*const ()>::VALUE;
    _checker.0 = tb.1;
    tb.0
};

fn main() {
    assert!(!IS_SEND_PTR);
}

I expected this to compile and pass the assertion.
Instead, this happened: compiler successfuly inferred type for tb, but for some reason didn’t use the associated constant from trait:

error[[E0277]](https://doc.rust-lang.org/stable/error-index.html#E0277): `*const ()` cannot be sent between threads safely
  --> src/main.rs:28:14
   |
28 |     let tb = IsSend::VALUE;
   |              ^^^^^^^^^^^^^ `*const ()` cannot be sent between threads safely
   |
   = help: the trait `Send` is not implemented for `*const ()`
note: required by a bound in `IsSend::<T>::VALUE`
  --> src/main.rs:14:9
   |
14 | impl<T: Send> IsSend<T> {
   |         ^^^^ required by this bound in `IsSend::<T>::VALUE`
15 |     const VALUE: TaggedBool<T> = TaggedBool(true, PhantomData);
   |           ----- required by a bound in this

Meta

Replicates on stable, beta and nightly on playground (v1.62.1, v1.63.0-beta9 and 1.65.0-nightly (2022-08-07 d394408) respectively).

[GoldsteinE]

Actually, I think it’s any associated items. It looks for me like the bug is somewhere in resolve_ty_and_res_fully_qualified_call, but I’m hugely underqualified for further debug.

I also failed to find any workaround. Even if I supply the correct answer, inference uses inherent impl and insists on incorrect answer:

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=c5fae9258adb2687d94f0c817cd70a5e

[GoldsteinE]

In the unlikely case someone faces the same problem, I found a workaround:

https://play.rust-lang.org/?version=stable&mode=debug&edition=2021&gist=2a5e77fa0621dc77a77da278fc23d9d7

[AstralSorcerer]

triage: still an issue on stable and nightly. I also wonder if it may be related to #102939.