Compiler error after running cargo clippy --fix

[typesanitizer]

Configurations checked:

• clippy 0.1.66 (42325c52 2022-11-11), cargo 1.67.0-nightly (9286a1beb 2022-11-04) (via cargo +nightly clippy --fix)
• clippy 0.1.65 (897e3755 2022-11-02), cargo 1.65.0 (4bc8f24d3 2022-10-20)

If you clone the repo with the initial commit:

https://github.com/typesanitizer/pichpich/tree/b971066734479f1bae779a0fa481fdc0d2b4e458

Then running cargo clippy --fix gives an error: (there are other warnings from clippy too but not showing those here)

after fixes were automatically applied the compiler reported errors within these files:

  * src/lib.rs

This likely indicates a bug in either rustc or cargo itself,
and we would appreciate a bug report! You're likely to see
a number of compiler warnings after this message which cargo
attempted to fix but failed. If you could open an issue at
https://github.com/rust-lang/rust/issues
quoting the full output of this command we'd be very appreciative!
Note that you may be able to make some more progress in the near-term
fixing code with the `--broken-code` flag

The following errors were reported:
error[E0277]: a value of type `std::vec::Vec<AppErrorNewtype>` cannot be built from an iterator over elements of type `std::boxed::Box<AppErrorNewtype>`
    --> src/lib.rs:30:24
     |
30   |               unrelated: errors
     |  ________________________^
31   | |                 .into_iter()
32   | |                 .map(|e| Box::new(AppErrorNewtype(e)))
     | |______________________________________________________^ value of type `std::vec::Vec<AppErrorNewtype>` cannot be built from `std::iter::Iterator<Item=std::boxed::Box<AppErrorNewtype>>`
33   |                   .collect(),
     |                    ------- required by a bound introduced by this call
     |
     = help: the trait `std::iter::FromIterator<std::boxed::Box<AppErrorNewtype>>` is not implemented for `std::vec::Vec<AppErrorNewtype>`
     = help: the trait `std::iter::FromIterator<T>` is implemented for `std::vec::Vec<T>`
note: required by a bound in `std::iter::Iterator::collect`
    --> /Users/varun/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/iter/traits/iterator.rs:1832:19
     |
1832 |     fn collect<B: FromIterator<Self::Item>>(self) -> B
     |                   ^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `std::iter::Iterator::collect`

error[E0599]: the method `as_ref` exists for reference `&AppErrorNewtype`, but its trait bounds were not satisfied
   --> src/lib.rs:57:45
    |
57  |             self.unrelated.iter().map(|b| b.as_ref() as &dyn Diagnostic),
    |                                             ^^^^^^ method cannot be called on `&AppErrorNewtype` due to unsatisfied trait bounds
...
79  | pub struct AppErrorNewtype(pub AppError);
    | -------------------------- doesn't satisfy `AppErrorNewtype: std::convert::AsRef<_>`
    |
    = note: the following trait bounds were not satisfied:
            `AppErrorNewtype: std::convert::AsRef<_>`
            which is required by `&AppErrorNewtype: std::convert::AsRef<_>`
note: the following trait must be implemented
   --> /Users/varun/.rustup/toolchains/nightly-aarch64-apple-darwin/lib/rustlib/src/rust/library/core/src/convert/mod.rs:218:1
    |
218 | pub trait AsRef<T: ?Sized> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: items from traits can only be used if the trait is implemented and in scope
    = note: the following trait defines an item `as_ref`, perhaps you need to implement it:
            candidate rust-lang/rust#1: `std::convert::AsRef`

error: aborting due to 2 previous errors

Some errors have detailed explanations: E0277, E0599.
For more information about an error, try `rustc --explain E0277`.
Original diagnostics will follow.

[ada4a]

I wasn't able to compile this on 1.65.0, since the code uses BTreeSet::pop_first, which was only stabilized in 1.66.0.

So I ran cargo +1.66.0 clippy --fix, then added --workspace, then added -- --Wclippy::pedantic, and got a different bug -- the following fix:

commit 4aa1843e6003139dc2563b737dd957f7aaf26aa7
Author: Ada Alakbarova <ada.alakbarova@proton.me>
Date:   Tue Aug 26 13:02:08 2025 +0200

    fix

diff --git a/crates/pichpich/src/miette_utils.rs b/crates/pichpich/src/miette_utils.rs
index 3532f02..628c807 100644
--- a/crates/pichpich/src/miette_utils.rs
+++ b/crates/pichpich/src/miette_utils.rs
@@ -44,6 +44,6 @@ impl<T: ?Sized + miette::Diagnostic> ErrorCount for T {
     fn error_count(&self) -> usize {
         1 + self
             .related()
-            .map_or(0, |b| b.map(|e| e.error_count()).sum())
+            .map_or(0, |b| b.map(miette_utils::ErrorCount::error_count).sum())
     }
 }

was incorrect: the path shouldn't have included miette_utils, since that's where the code was in the first place. I guess that's some --workspace funkiness. Anyway, I removed miette_utils::, ran the whole command again, got a bunch of fixes, but none of them resulted in an error.

Then I did the same thing with +nightly-2022-11-04, and got the exact same results.

Interestingly enough, the repo itself has a rust-toolchain file with nightly-2022-11-15 -- I repeated the whole procedure with that, but still wasn't able to reproduce the error shown.

It would've actually helped if the part after Original diagnostics will follow. wasn't omitted, but oh well.

I'm afraid there isn't really that much more that we could do with this, so:
@rustbot label S-triage