`needless_pass_by_value` cannot be controlled on a single parameter

[kpreid]

Summary

needless_pass_by_value is a lint whose validity very much depends on circumstances it can't fully know. (For example, a value consumed in the parameter list might be an allocation handle being passed to a free() function, which therefore semantically must be moved into the function.) Therefore, it should be possible to suppress it separately for each function parameter — but it is not.

Lint Name

needless_pass_by_value

Reproducer

I tried this code:

#![warn(clippy::needless_pass_by_value)] 

fn foo(#[allow(clippy::needless_pass_by_value)] s: String) {
    println!("{s}");
}

I saw this happen:

warning: this argument is passed by value, but not consumed in the function body
 --> src/lib.rs:3:52
  |
3 | fn foo(#[allow(clippy::needless_pass_by_value)] s: String) {
  |                                                    ^^^^^^ help: consider changing the type to: `&str`

I expected to see this happen: No lint message

Version

rustc 1.77.0 (aedd173a2 2024-03-17)
binary: rustc
commit-hash: aedd173a2c086e558c2b66d3743b344f977621a7
commit-date: 2024-03-17
host: x86_64-apple-darwin
release: 1.77.0
LLVM version: 17.0.6

[Centri3]

We could probably? lint on the input Ty's HirId itself since we just lint on the HirId of the function itself. Unless an attribute on an input parameter is nilled, but it isn't warned about so it doesn't seem so.

[BenjaminBrienen]

fn check(
    input: &str,
    expected_tree: Expect,
) {
    crate::check_entrypoint(input, ParseEntryPoint::File, &expected_tree);
}

warning: this argument is passed by value, but not consumed in the function body
 --> crates/parser/src/tests.rs:9:87
  |
9 |     #[expect(clippy::needless_pass_by_value, reason = "intended API")] expected_tree: Expect,
  |                                                                                       ^^^^^^
  |
  = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#needless_pass_by_value
help: consider taking a reference instead
  |
9 |     #[expect(clippy::needless_pass_by_value, reason = "intended API")] expected_tree: &Expect,
  |                                                                                       +