compiler tried to guess type for generic and type recurs on itself

[esavier]

Possibly related to #85063

It seems that the compiler tried to guess the type, which is recursive to itself, even if not required to.
Code below does have pieces that can hint the compiler to compile properly

#![recursion_limit = "8"] // doesn't matter, lower numbers makes error more readable

#[derive(Default)] pub struct Base;
pub struct Null;
pub struct Wrap<M>(M);

pub trait Pop<T> {
    type Output;
    fn pop(self, rhs: T) -> <Self as Pop<T>>::Output;
}

impl Pop<Null> for Base {
    type Output = Null;

    fn pop(self, rhs: Null) -> Self::Output { rhs }
}

impl<T> Pop<Wrap<T>> for Base where
    Base: Pop<T>,
    // === this line uncommented with the one mentioned in tests makes compiler act weird
    <Base as Pop<T>>::Output: Copy,
{
    type Output = <Base as Pop<T>>::Output;

    fn pop(self, rhs: Wrap<T>) -> Self::Output {
        let x = <Base as Pop<T>>::pop(self, rhs.0);
        x
    }
}

#[test]
fn test() {
    // === this line uncommented makes bug dissapear, regardless for the next one.
    // === probably it hints the compiler what T is,
    // Base.pop(Null);

    // === additionally this usage is also okay for the compiler.
    // === uncommenting this one hints the compiler
    // let b: Base = Base::default();
    // let _b = b.pop(Null);

    let _a = Pop::pop(Base, Null);
    
    // === this below works 
    // let _a = <Base as Pop<Null>>::pop(Base, Null);

    // === same usage as above, however this usage will not help
    // let b: Base = Base::default();
    // let _b = b.pop(Null);
}

fn main() {
    todo!();
}

[manfredvw]

The compiler should eliminate the second impl from consideration immediately because the second parameter to Pop::pop with type Null mismatches the Wrap<T>. Instead, it appears to try to solve for the type parameters through the trait bounds before first considering the match between arguments and parameters in the function call, which leads to the endless recursion. Reordering of actions in this process should solve this case (and hopefully many like it).