Incorrect error for overflow in bound evaluation

[wthrowe]

#![allow(unconditional_recursion)]

struct X<T>(T);

trait A {
    fn foo(self);
}

impl<T> A for T {
    fn foo(self) {
        X(self).foo() // <-- error points here
    }
}

fn main() {
    1.foo();
}

reports error: overflow evaluating the requirement i32 : core::marker::Sized [E0275]. While this code certainly shouldn't work, I would not expect proving i32: Sized to be the problematic part.

(This is similar to #23714, but I think that's about the example failing to compile rather than the nonsense error.)

[arielb1]

The note in the error message correctly tells you that the problem involves the type X<X<X<X<X<X<X<X<i32>>>>>>>>.

[arielb1]

The error here is a recursive monomorphization (<T as A>::foo requiring <X<T> as A>::foo) that bails out in trait selection. The error message sucks.

[Mark-Simulacrum]

Today's error message is quite a bit more clear, I think, since it indicates that the problem is with this piece of code and with what expansion. As such, I'm going to go ahead and close this.

error: reached the recursion limit while instantiating `<T as A><X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<X<i32>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>::foo`
  --> test.rs:10:5
   |
10 | /     fn foo(self) {
11 | |         X(self).foo() // <-- error points here
12 | |     }
   | |_____^