From f35d87f21101b2310f9466f6a00253d05041107e Mon Sep 17 00:00:00 2001 From: Guillaume Gomez Date: Fri, 16 Feb 2024 17:44:01 +0100 Subject: [PATCH] Add `unneeded_clippy_cfg_attr` lint --- CHANGELOG.md | 1 + clippy_lints/src/attrs.rs | 97 +++++++++++++++++++++++++++++- clippy_lints/src/declared_lints.rs | 1 + 3 files changed, 98 insertions(+), 1 deletion(-) diff --git a/CHANGELOG.md b/CHANGELOG.md index b35475c7340..c2f47ad9720 100644 --- a/CHANGELOG.md +++ b/CHANGELOG.md @@ -5726,6 +5726,7 @@ Released 2018-09-13 [`unknown_clippy_lints`]: https://rust-lang.github.io/rust-clippy/master/index.html#unknown_clippy_lints [`unnecessary_box_returns`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_box_returns [`unnecessary_cast`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast +[`unnecessary_clippy_cfg`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_clippy_cfg [`unnecessary_fallible_conversions`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_fallible_conversions [`unnecessary_filter_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_filter_map [`unnecessary_find_map`]: https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_find_map diff --git a/clippy_lints/src/attrs.rs b/clippy_lints/src/attrs.rs index 755f4ad3c89..f90a7dbbfe5 100644 --- a/clippy_lints/src/attrs.rs +++ b/clippy_lints/src/attrs.rs @@ -1,7 +1,9 @@ //! checks for attributes use clippy_config::msrvs::{self, Msrv}; -use clippy_utils::diagnostics::{span_lint, span_lint_and_help, span_lint_and_sugg, span_lint_and_then}; +use clippy_utils::diagnostics::{ + span_lint, span_lint_and_help, span_lint_and_note, span_lint_and_sugg, span_lint_and_then, +}; use clippy_utils::is_from_proc_macro; use clippy_utils::macros::{is_panic, macro_backtrace}; use clippy_utils::source::{first_line_of_span, is_present_in_source, snippet_opt, without_block_comments}; @@ -459,6 +461,30 @@ "usage of `cfg(feature = \"cargo-clippy\")` instead of `cfg(clippy)`" } +declare_clippy_lint! { + /// ### What it does + /// Checks for `#[cfg_attr(clippy, allow(clippy::lint))]` + /// and suggests to replace it with `#[allow(clippy::lint)]`. + /// + /// ### Why is this bad? + /// There is no reason to put clippy attributes behind a clippy `cfg` as they are not + /// run by anything else than clippy. + /// + /// ### Example + /// ```no_run + /// #![cfg_attr(clippy, allow(clippy::deprecated_cfg_attr))] + /// ``` + /// + /// Use instead: + /// ```no_run + /// #![allow(clippy::deprecated_cfg_attr)] + /// ``` + #[clippy::version = "1.78.0"] + pub UNNECESSARY_CLIPPY_CFG, + suspicious, + "usage of `cfg_attr(clippy, allow(clippy::lint))` instead of `allow(clippy::lint)`" +} + declare_lint_pass!(Attributes => [ ALLOW_ATTRIBUTES_WITHOUT_REASON, INLINE_ALWAYS, @@ -821,6 +847,7 @@ pub struct EarlyAttributes { NON_MINIMAL_CFG, MAYBE_MISUSED_CFG, DEPRECATED_CLIPPY_CFG_ATTR, + UNNECESSARY_CLIPPY_CFG, ]); impl EarlyLintPass for EarlyAttributes { @@ -958,6 +985,74 @@ fn check_deprecated_cfg_attr(cx: &EarlyContext<'_>, attr: &Attribute, msrv: &Msr ); } else { check_deprecated_cfg_recursively(cx, feature_item); + if let Some(behind_cfg_attr) = items[1].meta_item() { + check_clippy_cfg_attr(cx, feature_item, behind_cfg_attr, attr); + } + } + } +} + +fn check_clippy_cfg_attr( + cx: &EarlyContext<'_>, + cfg_attr: &rustc_ast::MetaItem, + behind_cfg_attr: &rustc_ast::MetaItem, + attr: &Attribute, +) { + if cfg_attr.has_name(sym::clippy) + && let Some(ident) = behind_cfg_attr.ident() + // FIXME: replace with `from_symbol` once https://github.com/rust-lang/rust/pull/121230 + // is merged. + && Level::from_str(ident.name.as_str()).is_some() + && let Some(items) = behind_cfg_attr.meta_item_list() + { + let nb_items = items.len(); + let mut clippy_lints = Vec::with_capacity(items.len()); + for item in items { + if let Some(meta_item) = item.meta_item() + && let [part1, _] = meta_item.path.segments.as_slice() + && part1.ident.name == sym::clippy + { + clippy_lints.push(item.span()); + } + } + if clippy_lints.is_empty() { + return; + } + if nb_items == clippy_lints.len() { + if let Some(snippet) = snippet_opt(cx, behind_cfg_attr.span) { + span_lint_and_sugg( + cx, + UNNECESSARY_CLIPPY_CFG, + attr.span, + "no need to put clippy lints behind a `clippy` cfg", + "replace with", + format!( + "#{}[{}]", + if attr.style == AttrStyle::Inner { "!" } else { "" }, + snippet + ), + Applicability::MachineApplicable, + ); + } + } else { + let snippet = clippy_lints + .iter() + .filter_map(|sp| snippet_opt(cx, *sp)) + .collect::>() + .join(","); + span_lint_and_note( + cx, + UNNECESSARY_CLIPPY_CFG, + clippy_lints, + "no need to put clippy lints behind a `clippy` cfg", + None, + &format!( + "write instead: `#{}[{}({})]`", + if attr.style == AttrStyle::Inner { "!" } else { "" }, + ident.name, + snippet + ), + ); } } } diff --git a/clippy_lints/src/declared_lints.rs b/clippy_lints/src/declared_lints.rs index 60744fee34d..76595e2e26e 100644 --- a/clippy_lints/src/declared_lints.rs +++ b/clippy_lints/src/declared_lints.rs @@ -60,6 +60,7 @@ crate::attrs::MISMATCHED_TARGET_OS_INFO, crate::attrs::NON_MINIMAL_CFG_INFO, crate::attrs::SHOULD_PANIC_WITHOUT_EXPECT_INFO, + crate::attrs::UNNECESSARY_CLIPPY_CFG_INFO, crate::attrs::USELESS_ATTRIBUTE_INFO, crate::await_holding_invalid::AWAIT_HOLDING_INVALID_TYPE_INFO, crate::await_holding_invalid::AWAIT_HOLDING_LOCK_INFO,