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Diffstat (limited to '')
-rw-r--r-- | src/tools/clippy/clippy_lints/src/disallowed_methods.rs | 113 |
1 files changed, 113 insertions, 0 deletions
diff --git a/src/tools/clippy/clippy_lints/src/disallowed_methods.rs b/src/tools/clippy/clippy_lints/src/disallowed_methods.rs new file mode 100644 index 000000000..53973ab79 --- /dev/null +++ b/src/tools/clippy/clippy_lints/src/disallowed_methods.rs @@ -0,0 +1,113 @@ +use clippy_utils::diagnostics::span_lint_and_then; +use clippy_utils::{fn_def_id, get_parent_expr, path_def_id}; + +use rustc_hir::{def::Res, def_id::DefIdMap, Expr, ExprKind}; +use rustc_lint::{LateContext, LateLintPass}; +use rustc_session::{declare_tool_lint, impl_lint_pass}; + +use crate::utils::conf; + +declare_clippy_lint! { + /// ### What it does + /// Denies the configured methods and functions in clippy.toml + /// + /// Note: Even though this lint is warn-by-default, it will only trigger if + /// methods are defined in the clippy.toml file. + /// + /// ### Why is this bad? + /// Some methods are undesirable in certain contexts, and it's beneficial to + /// lint for them as needed. + /// + /// ### Example + /// An example clippy.toml configuration: + /// ```toml + /// # clippy.toml + /// disallowed-methods = [ + /// # Can use a string as the path of the disallowed method. + /// "std::boxed::Box::new", + /// # Can also use an inline table with a `path` key. + /// { path = "std::time::Instant::now" }, + /// # When using an inline table, can add a `reason` for why the method + /// # is disallowed. + /// { path = "std::vec::Vec::leak", reason = "no leaking memory" }, + /// ] + /// ``` + /// + /// ```rust,ignore + /// // Example code where clippy issues a warning + /// let xs = vec![1, 2, 3, 4]; + /// xs.leak(); // Vec::leak is disallowed in the config. + /// // The diagnostic contains the message "no leaking memory". + /// + /// let _now = Instant::now(); // Instant::now is disallowed in the config. + /// + /// let _box = Box::new(3); // Box::new is disallowed in the config. + /// ``` + /// + /// Use instead: + /// ```rust,ignore + /// // Example code which does not raise clippy warning + /// let mut xs = Vec::new(); // Vec::new is _not_ disallowed in the config. + /// xs.push(123); // Vec::push is _not_ disallowed in the config. + /// ``` + #[clippy::version = "1.49.0"] + pub DISALLOWED_METHODS, + style, + "use of a disallowed method call" +} + +#[derive(Clone, Debug)] +pub struct DisallowedMethods { + conf_disallowed: Vec<conf::DisallowedMethod>, + disallowed: DefIdMap<usize>, +} + +impl DisallowedMethods { + pub fn new(conf_disallowed: Vec<conf::DisallowedMethod>) -> Self { + Self { + conf_disallowed, + disallowed: DefIdMap::default(), + } + } +} + +impl_lint_pass!(DisallowedMethods => [DISALLOWED_METHODS]); + +impl<'tcx> LateLintPass<'tcx> for DisallowedMethods { + fn check_crate(&mut self, cx: &LateContext<'_>) { + for (index, conf) in self.conf_disallowed.iter().enumerate() { + let segs: Vec<_> = conf.path().split("::").collect(); + if let Res::Def(_, id) = clippy_utils::def_path_res(cx, &segs) { + self.disallowed.insert(id, index); + } + } + } + + fn check_expr(&mut self, cx: &LateContext<'tcx>, expr: &'tcx Expr<'_>) { + let uncalled_path = if let Some(parent) = get_parent_expr(cx, expr) + && let ExprKind::Call(receiver, _) = parent.kind + && receiver.hir_id == expr.hir_id + { + None + } else { + path_def_id(cx, expr) + }; + let def_id = match uncalled_path.or_else(|| fn_def_id(cx, expr)) { + Some(def_id) => def_id, + None => return, + }; + let conf = match self.disallowed.get(&def_id) { + Some(&index) => &self.conf_disallowed[index], + None => return, + }; + let msg = format!("use of a disallowed method `{}`", conf.path()); + span_lint_and_then(cx, DISALLOWED_METHODS, expr.span, &msg, |diag| { + if let conf::DisallowedMethod::WithReason { + reason: Some(reason), .. + } = conf + { + diag.note(&format!("{} (from clippy.toml)", reason)); + } + }); + } +} |