Try different Deref/PartialEq orderings before erroring

[djc]

I just got this error:

djc@djc-mbp cargo $ cargo check
   Compiling cargo v0.27.0 (file:///Users/djc/src/cargo)
error[E0308]: mismatched types
   --> src/cargo/core/summary.rs:150:58
    |
150 |                 dependencies.iter().find(|d| d.name() == dep_name)
    |                                                          ^^^^^^^^ expected struct `core::interning::InternedString`, found &str
    |
    = note: expected type `core::interning::InternedString`
               found type `&str`

InternedString implements Deref<Target = str>, so I'd expected that this could somehow be made to work. *d.name() == *dep_name seems to work, but dereferencing explicitly always feels bad. Is there a better way out here? If not, could this solution be suggested?

cc @estebank @ehuss

[frewsxcv]

somewhat related to dereferencing and PartialEq: #39942

[steveklabnik]

I tried to make a minimal reproduction here https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=be29ae6b6632484edf22da25539d95eb

I am not sure if it is or not. @djc any thoughts on this?

[djc]

#39942 has been closed as a duplicate of #40660, so I suppose that's the canonical issue now at least in terms of diagnostics.

@steveklabnik thanks for the minimal reproduction. I've amended it slightly to https://play.rust-lang.org/?version=stable&mode=debug&edition=2018&gist=d721a2cdccb159604f5fed06c5726e0f, which has a more concise error now:

error[E0308]: mismatched types
  --> src/main.rs:22:45
   |
22 |     dependencies.into_iter().find(|&d| d == dep_name);
   |                                             ^^^^^^^^ expected struct `InternedString`, found `&str`

[estebank]

Current output:

error[[E0308]](https://doc.rust-lang.org/stable/error_codes/E0308.html): mismatched types
  --> src/main.rs:22:45
   |
22 |     dependencies.into_iter().find(|&d| d == dep_name);
   |                                        -    ^^^^^^^^ expected `InternedString`, found `&str`
   |                                        |
   |                                        expected because this is `InternedString`
   |
help: try wrapping the expression in `InternedString`
   |
22 |     dependencies.into_iter().find(|&d| d == InternedString(dep_name));
   |                                             +++++++++++++++        +