Warn on vec.clone().some_vec_method()

What it does

Warn when chaining sort(), dedup(), or other method that changes the vector after to_vec() or clone(). Example:

// Probably an error as sort() returns () not a vec
let mut new_vec = old_vec.clone().sort();

// This is probably what you wanted
let mut new_vec = old_vec.clone()
mut new_vec.sort();

Categories (optional)

• Kind: clippy::correctness

What is the advantage of the recommended code over the original code

I'm not sure.

Drawbacks

The Rust compiler will correctly tell if () uses a vector function later.

Example

let mut new_vec = old_vec.clone().sort();

// This will error, () does not have push() method
new_vec.push(0);

// No error here, () implements Debug (or is it Default? that allows printing below)
println!("New vec: {}", new_vec);

// No error here, () has a clone() method
let cloned_vec = new_vec.clone();

Start by reviewing the requested Rust examples and the existing Clippy lint conventions; no implementation files or tests are named in the issue. Define the supported vector-mutating method chains and their diagnostic behavior, then add coverage showing warnings for the erroneous chains and no warning for the separate mutable-vector form.