Disable code Action for clippy::needless_return

[aminya]

Rust-analyzer has started to give code action suggestions for removing return from my code despite me allowing clippy::needless_return via #![allow(clippy::needless_return)].

In my coding style, I do not like my returns to be implicit, and I don't really align with the push to force not using return statements in the Rust tooling (e.g. Clippy, Rust-analyzer, etc).

Could you add an option to remove this code action, or respect the clippy configuration enabled at the module level?

rust-analyzer version: 0.4.1838-standalone

rustc version: rustc 1.75.0-nightly (42b1224e9 2023-10-15)

relevant settings: (eg. client settings, or environment variables like CARGO, RUSTC, RUSTUP_HOME or CARGO_HOME)

The offending feature:

#16460

[lnicola]

Unfortunately, I don't think we respect #[allow(clippy::needless_return)] yet, but in VS Code you can disable it using:

{
    "rust-analyzer.diagnostics.disabled": [
        "needless_return"
    ]
}

[j0ni]

Weirdly, I see this showing up via eglot in emacs on a function which does not contain an explicit return.

It's annotated with a #[tokio::main] macro, so I guess the problem lies somewhere in the expanded code? I look forward to a working lints.rust (or lints.clippy I guess) entry for this!

[I-Info]

Maybe this rule should not be applied on the macro expansions. 🤔

[Veykril]

Our filtering for diagnostic level attributes is somewhat broken wrt to macros, that is a known issue.

[lnicola]

It should respect #[allow(clippy::needless_return)], but tokio::main doesn't even seem to expand to that. It only has #[allow(clippy::expect_used, clippy::diverging_sub_expression)] for me.

[Veykril]

Might be that needless_return doesn't trigger on macro expansions with clippy

[lnicola]

No, I think it's something kind of heuristic:

// no warning
fn main() {
    return tokio::runtime::Builder::new_current_thread()
        .enable_all()
        .build()
        .expect("Failed building the Runtime")
        .block_on(async {});
}

// warning
fn main() {
    return tokio::runtime::Runtime::new()
        .expect("Failed building the Runtime")
        .block_on(async {});
}

// warning
fn main() {
    return tokio::runtime::Builder::new_current_thread()
        .build()
        .expect("Failed building the Runtime")
        .block_on(async {});
}

[lnicola]

I suspect it's this check: https://github.com/rust-lang/rust-clippy/blob/d2f76f7/clippy_lints/src/returns.rs#L378-L381.

[Veykril]

Oh, that's probably due to temporaries? (Then we most likelyneed that as well)

[lnicola]

Yeah: https://github.com/rust-lang/rust-clippy/blame/48b4aea/clippy_lints/src/returns.rs#L19-L20

Known problems: If the computation returning the value borrows a local variable, removing the return may run afoul of the borrow checker.

Sounds like a limitation of Clippy itself (it's too conservative here), but we probably want to match it anyway.

[arnfaldur]

Is there any way to disable this behavior?

[lnicola]

@arnfaldur see my comment at the top.

[arnfaldur]

@lnicola ah, sorry, didn't think too much about that as I don't use VSCode. There must be some way to configure LSPs in vim/emacs like that. I'll figure it out, thanks.

[j0ni]

@arnfaldur and anyone else who lands here looking for a workaround in emacs using eglot, here is the configuration tweak I have, which appears to work:

(with-eval-after-load 'eglot
  (add-to-list 'eglot-server-programs
               '((rust-ts-mode rust-mode) .
                 ("rust-analyzer"
                  :initializationOptions
                  (:check
                   (:command "clippy")
                   :diagnostics
                   (:disabled ["needless_return"
                               "clippy::needless_return"]))))))

The :check (:command "clippy") part is unrelated, but demonstrates how to compose different config options. I'm not sure whether the clippy:: prefixed item is doing any work here, it was just a piece of spaghetti I threw at the wall which was stuck there when it started working :)

[SergSpice]

Why is this is even in the project?, one of the things that I hate about Go lsp and ESLint is that they force you to have a code style that is horrendous, I think the whole "needless_return" is an overreach, I haven't even been able to remove this in my Neovim config, and is not like I have an old soul and I'm not open to new things, it's because my project now is full of warnings since I updated the version, and this doesn't even makes sense, is a fricking macro!!!!:

[leelhn2345]

Why is this is even in the project?, one of the things that I hate about Go linter and ESLint is that they force you to have a code style that is horrendous, I think the whole "needless_return" is an overreach, I haven't even been able to remove this in my Neovim config, and is not like I have an old soul and I'm not open to new things, it's because my project now is full of warnings since I updated the version, and this doesn't even makes sense, is a fricking macro!!!!:

until there's a permanent change to this,
you can configure rust analyzer to disable the warning.

          ["rust-analyzer"] = {
            diagnostics = {
              disabled = {
                "needless_return",
              },
            },
          }

this is from my rustacean.nvim plugin, but i believe the settings should be similiar to other lsp plugins.

[conradogarciaberrotaran]

for lspconfig within mason:

require("mason-lspconfig").setup_handlers({
  ["rust_analyzer"] = function()
    require("lspconfig").rust_analyzer.setup({
      on_attach = on_attach,
      capabilities = capabilities,
      settings = {
        ["rust-analyzer"] = {
          diagnostics = {
            disabled = {
              "needless_return",
            },
          },
        },
      },
    })
  end,
})

[Veykril]

The lint shouldn't trigger by default anymore next release until opted-in, 676455f

[conradogarciaberrotaran]

It has to be released right?
If so, would you update this: https://github.com/mason-org/mason-registry/blob/main/packages/rust-analyzer/package.yaml
or let me know to do it myself.

Thanks!

[lnicola]

It will be released on Monday, or you could use the nightly (I've triggered a build now, should finish in about 15 minutes). We don't own mason-registry, but you can probably download a binary and replace it manually.

[conradogarciaberrotaran]

I'll create a PR when it's released.

Thanks :)

[lnicola]

I imagine they might not want to use nightlies, so it's probably fine to wait until Monday.

[conradogarciaberrotaran]

mason-registry's versions are auto updated :)
mason-org/mason-registry@696a25a

[gamedev-pnc]

{
    "rust-analyzer.diagnostics.disabled": [
        "needless_return"
    ]
}

Didn't work for me on VSCode and clippy 0.1.79 (129f3b99 2024-06-10). Are there other solutions?

[gamedev-pnc]

#![allow(clippy::needless_return)] -- works in clippy 0.1.80.
Thanks!

[Ritzier]

default_settings = {
    checkOnSave = {
        false
    }
}

For my configuraiotn, disable checkOnSave