`equatable_if_let` suggests wrong code when it involves a reference

[sozysozbot]

Summary

equatable_if_let tries to replace a pattern into a ==, but the two differ slightly in their semantics when it comes to reference. Hence the current implementation creates a suggestion that causes a type mismatch error when adopted.

Reproducer

I tried this code:

#![warn(clippy::pedantic, clippy::nursery)]
fn bar() {todo!()}
fn baz() {todo!()}

pub fn foo(cs: &[char]) {
    let mut iter = cs.iter();
    if let Some('i') = iter.next() {
        bar();
    } else {
        baz();
    }
}

I expected to see this happen: Clippy suggests

try: `iter.next() == Some(&'i')`

Instead, this happened: Clippy suggested

try: `iter.next() == Some('i')`

which is a wrong suggestion because replacing the original code with this snippet causes a type error.

Version

rustc 1.60.0 (7737e0b5c 2022-04-04)
binary: rustc
commit-hash: 7737e0b5c4103216d6fd8cf941b7ab9bdbaace7c
commit-date: 2022-04-04
host: x86_64-pc-windows-msvc
release: 1.60.0
LLVM version: 14.0.0

Additional Labels

@rustbot label +l-suggestion-causes-error

[rustbot]

Error: Label l-suggestion-causes-error can only be set by Rust team members

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