Strange 'expected' and 'found'

[hirrolot]

Consider these two examples:

1. https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=1e43b7cb813eeac58982933266b7bdf3
   Error:

error[E0271]: type mismatch resolving `<std::slice::Iter<'_, {integer}> as std::iter::Iterator>::Item == i32`
 --> src/main.rs:4:5
  |
1 | fn consume<I: Iterator<Item = i32>>(_: I) {}
  |    -------             ---------- required by this bound in `consume`
...
4 |     consume([1, 2, 3].into_iter());
  |     ^^^^^^^ expected reference, found i32
  |
  = note: expected type `&{integer}`
             found type `i32`

2. https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=528121c8b1f50ed2c761e9932f7d792a
   Error:

error[E0308]: mismatched types
 --> src/main.rs:4:13
  |
4 |     consume(&123);
  |             ^^^^
  |             |
  |             expected i32, found &{integer}
  |             help: consider removing the borrow: `123`
  |
  = note: expected type `i32`
             found type `&{integer}`

expected in the first example's error message is related to the call's context, but in the second one, it is related to the function's signature. Is it a bug?

rustc

1.39.0 stable

[memoryruins]

Thanks for reporting. This was fixed in #65977

Nightly's current output for 1

error[E0271]: type mismatch resolving `<std::slice::Iter<'_, {integer}> as std::iter::Iterator>::Item == i32`
 --> src/main.rs:4:5
  |
1 | fn consume<I: Iterator<Item = i32>>(_: I) {}
  |    -------             ---------- required by this bound in `consume`
...
4 |     consume([1, 2, 3].into_iter());
  |     ^^^^^^^ expected `i32`, found reference
  |
  = note:   expected type `i32`
          found reference `&{integer}`

1.41.0-nightly 2019-12-16 99b89533d4cdf7682ea4

[jonas-schievink]

Closing as fixed.

[hirrolot]

Nice!