Compilation fails with "overflow evaluating the requirement" when an unrelated impl for a reference is present

[koute]

Consider the following code:

struct Wrapper<T>(T);
impl<'a, T> IntoIterator for &'a Wrapper<T> where &'a T: IntoIterator {
    type Item = <&'a T as IntoIterator>::Item;
    type IntoIter = <&'a T as IntoIterator>::IntoIter;
    fn into_iter(self) -> Self::IntoIter {
        self.0.into_iter()
    }
}

pub fn foobar<'a, T>(it: &'a T) where &'a T: IntoIterator, T: 'a {}

fn main() {
    foobar(&vec![0_u8]);
}

Playground

Trying to compile it results in the following error:

error[E0275]: overflow evaluating the requirement `&_: IntoIterator`
  --> src/main.rs:13:5
   |
10 | pub fn foobar<'a, T>(it: &'a T) where &'a T: IntoIterator, T: 'a {}
   |                                              ------------ required by this bound in `foobar`
...
13 |     foobar(&vec![0_u8]);
   |     ^^^^^^
   |
   = help: consider adding a `#![recursion_limit="256"]` attribute to your crate (`playground`)
   = note: required because of the requirements on the impl of `IntoIterator` for `&Wrapper<_>`
   = note: 127 redundant requirements hidden
   = note: required because of the requirements on the impl of `IntoIterator` for `&Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<Wrapper<_>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>`

If you comment out the IntoIterator impl or the call to foobar then it compiles successfully.

Might be related to #80542, #78982 and possibly others.

Meta

Affected versions:

• 1.52.0-nightly (2021-03-14 d6eaea1)
• 1.50.0-stable
• 1.0.0-stable

[estebank]

You can change the code to either not include the borrow in the trait bound or change foobar to not take a borrow.

The bug is valid as a bad diagnostic.