FP from_over_into: type_alias_impl_trait

[matthiaskrgr]

Summary

.

Lint Name

from_over_into

Reproducer

I tried this code:

#![feature(type_alias_impl_trait)]

type T = impl Sized;

struct Foo;

impl Into<T> for Foo {
    fn into(self) -> T {}
}

fn main(){
    let _: T = Foo.into();
}

I saw this happen:
cargo clippy --fix -- -Aclippy::all -Wclippy::from_over_into

    Checking f v0.1.0 (/tmp/f)
warning: failed to automatically apply fixes suggested by rustc to crate `f`

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

  * src/main.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[E0119]: conflicting implementations of trait `std::convert::From<T>` for type `T`
 --> src/main.rs:7:1
  |
7 | impl From<Foo> for T {
  | ^^^^^^^^^^^^^^^^^^^^
  |
  = note: conflicting implementation in crate `core`:
          - impl<T> std::convert::From<T> for T;

error: aborting due to previous error

For more information about this error, try `rustc --explain E0119`.
Original diagnostics will follow.

warning: an implementation of `From` is preferred since it gives you `Into<_>` for free where the reverse isn't true
 --> src/main.rs:7:1
  |
7 | impl Into<T> for Foo {
  | ^^^^^^^^^^^^^^^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#from_over_into
  = note: requested on the command line with `-W clippy::from-over-into`
help: replace the `Into` implentation with `From<Foo>`
  |
7 ~ impl From<Foo> for T {
8 ~     fn from(val: Foo) -> Self {}
  |

warning: `f` (bin "f") generated 1 warning (run `cargo fix --bin "f"` to apply 1 suggestion)
warning: `f` (bin "f" test) generated 1 warning (1 duplicate)
    Finished dev [unoptimized + debuginfo] target(s) in 0.16s

I expected to see this happen:

Version

No response

Additional Labels

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