error: calling `to_string` on `&&str`
  --> $DIR/inefficient_to_string.rs:12:21
   |
LL |     let _: String = rrstr.to_string();
   |                     ^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(*rrstr).to_string()`
   |
note: lint level defined here
  --> $DIR/inefficient_to_string.rs:2:9
   |
LL | #![deny(clippy::inefficient_to_string)]
   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
   = help: `&str` implements `ToString` through a slower blanket impl, but `str` has a fast specialization of `ToString`

error: calling `to_string` on `&&&str`
  --> $DIR/inefficient_to_string.rs:13:21
   |
LL |     let _: String = rrrstr.to_string();
   |                     ^^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(**rrrstr).to_string()`
   |
   = help: `&&str` implements `ToString` through a slower blanket impl, but `str` has a fast specialization of `ToString`

error: calling `to_string` on `&&std::string::String`
  --> $DIR/inefficient_to_string.rs:21:21
   |
LL |     let _: String = rrstring.to_string();
   |                     ^^^^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(*rrstring).to_string()`
   |
   = help: `&std::string::String` implements `ToString` through a slower blanket impl, but `std::string::String` has a fast specialization of `ToString`

error: calling `to_string` on `&&&std::string::String`
  --> $DIR/inefficient_to_string.rs:22:21
   |
LL |     let _: String = rrrstring.to_string();
   |                     ^^^^^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(**rrrstring).to_string()`
   |
   = help: `&&std::string::String` implements `ToString` through a slower blanket impl, but `std::string::String` has a fast specialization of `ToString`

error: calling `to_string` on `&&std::borrow::Cow<'_, str>`
  --> $DIR/inefficient_to_string.rs:30:21
   |
LL |     let _: String = rrcow.to_string();
   |                     ^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(*rrcow).to_string()`
   |
   = help: `&std::borrow::Cow<'_, str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<'_, str>` has a fast specialization of `ToString`

error: calling `to_string` on `&&&std::borrow::Cow<'_, str>`
  --> $DIR/inefficient_to_string.rs:31:21
   |
LL |     let _: String = rrrcow.to_string();
   |                     ^^^^^^^^^^^^^^^^^^ help: try dereferencing the receiver: `(**rrrcow).to_string()`
   |
   = help: `&&std::borrow::Cow<'_, str>` implements `ToString` through a slower blanket impl, but `std::borrow::Cow<'_, str>` has a fast specialization of `ToString`

error: aborting due to 6 previous errors