op_ref invalid recommendation

[ghost]

Here is my situation:

#[allow(dead_code)]
fn eg() {
    let a = "a".to_string();
    let b = "a";

    if b < &a {
        println!("OK");
    }
}

warning: taken reference of right operand
 --> src/lib.rs:6:8
  |
6 |     if b < &a {
  |        ^^^^^^
  |
  = note: #[warn(op_ref)] on by default
help: dereference the left operand instead
  |     if *b < a {
  = help: for further information visit https://github.com/Manishearth/rust-clippy/wiki#op_ref

After applying the recommendation...

#[allow(dead_code)]
fn eg() {
    let a = "a".to_string();
    let b = "a";

    if *b < a {
        println!("OK");
    }
}

error[E0308]: mismatched types
 --> src/lib.rs:6:13
  |
6 |     if *b < a {
  |             ^ expected str, found struct `std::string::String`
  |
  = note: expected type `str`
             found type `std::string::String`