diff --git a/clippy_lints/src/use_self.rs b/clippy_lints/src/use_self.rs index f71dfd024999..5f0dd61cf2c6 100644 --- a/clippy_lints/src/use_self.rs +++ b/clippy_lints/src/use_self.rs @@ -2,17 +2,18 @@ use clippy_utils::diagnostics::span_lint_and_sugg; use clippy_utils::ty::same_type_and_consts; use clippy_utils::{in_macro, meets_msrv, msrvs}; use if_chain::if_chain; +use rustc_data_structures::fx::FxHashSet; use rustc_errors::Applicability; use rustc_hir::{ self as hir, def::{CtorOf, DefKind, Res}, def_id::LocalDefId, intravisit::{walk_ty, NestedVisitorMap, Visitor}, - Expr, ExprKind, FnRetTy, FnSig, GenericArg, HirId, Impl, ImplItemKind, Item, ItemKind, Node, Path, QPath, TyKind, + Expr, ExprKind, FnRetTy, FnSig, GenericArg, HirId, Impl, ImplItemKind, Item, ItemKind, Path, QPath, TyKind, }; use rustc_lint::{LateContext, LateLintPass, LintContext}; use rustc_middle::hir::map::Map; -use rustc_middle::ty::{AssocKind, Ty}; +use rustc_middle::ty::AssocKind; use rustc_semver::RustcVersion; use rustc_session::{declare_tool_lint, impl_lint_pass}; use rustc_span::Span; @@ -73,10 +74,9 @@ impl UseSelf { #[derive(Debug)] enum StackItem { Check { - hir_id: HirId, - impl_trait_ref_def_id: Option, - types_to_skip: Vec, - types_to_lint: Vec, + impl_id: LocalDefId, + in_body: u32, + types_to_skip: FxHashSet, }, NoCheck, } @@ -86,60 +86,41 @@ impl_lint_pass!(UseSelf => [USE_SELF]); const SEGMENTS_MSG: &str = "segments should be composed of at least 1 element"; impl<'tcx> LateLintPass<'tcx> for UseSelf { - fn check_item(&mut self, cx: &LateContext<'_>, item: &Item<'_>) { + fn check_item(&mut self, _cx: &LateContext<'_>, item: &Item<'_>) { + if !is_item_interesting(item) { + // This does two things: + // 1) Reduce needless churn on `self.stack` + // 2) Don't push `StackItem::NoCheck` when entering `ItemKind::OpaqueTy`, + // in order to lint `foo() -> impl <..>` + return; + } // We push the self types of `impl`s on a stack here. Only the top type on the stack is // relevant for linting, since this is the self type of the `impl` we're currently in. To // avoid linting on nested items, we push `StackItem::NoCheck` on the stack to signal, that // we're in an `impl` or nested item, that we don't want to lint - // - // NB: If you push something on the stack in this method, remember to also pop it in the - // `check_item_post` method. - match &item.kind { - ItemKind::Impl(Impl { - self_ty: hir_self_ty, - of_trait, - .. - }) => { - let should_check = if let TyKind::Path(QPath::Resolved(_, item_path)) = hir_self_ty.kind { - let parameters = &item_path.segments.last().expect(SEGMENTS_MSG).args; - parameters.as_ref().map_or(true, |params| { - !params.parenthesized && !params.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_))) - }) - } else { - false - }; - let impl_trait_ref_def_id = of_trait.as_ref().map(|_| cx.tcx.hir().local_def_id(item.hir_id())); - if should_check { - self.stack.push(StackItem::Check { - hir_id: hir_self_ty.hir_id, - impl_trait_ref_def_id, - types_to_lint: Vec::new(), - types_to_skip: Vec::new(), - }); - } else { - self.stack.push(StackItem::NoCheck); + let stack_item = if_chain! { + if let ItemKind::Impl(Impl { self_ty, .. }) = item.kind; + if let TyKind::Path(QPath::Resolved(_, item_path)) = self_ty.kind; + let parameters = &item_path.segments.last().expect(SEGMENTS_MSG).args; + if parameters.as_ref().map_or(true, |params| { + !params.parenthesized && !params.args.iter().any(|arg| matches!(arg, GenericArg::Lifetime(_))) + }); + then { + StackItem::Check { + impl_id: item.def_id, + in_body: 0, + types_to_skip: std::iter::once(self_ty.hir_id).collect(), } - }, - ItemKind::Static(..) - | ItemKind::Const(..) - | ItemKind::Fn(..) - | ItemKind::Enum(..) - | ItemKind::Struct(..) - | ItemKind::Union(..) - | ItemKind::Trait(..) => { - self.stack.push(StackItem::NoCheck); - }, - _ => (), - } + } else { + StackItem::NoCheck + } + }; + self.stack.push(stack_item); } fn check_item_post(&mut self, _: &LateContext<'_>, item: &Item<'_>) { - use ItemKind::{Const, Enum, Fn, Impl, Static, Struct, Trait, Union}; - match item.kind { - Impl { .. } | Static(..) | Const(..) | Fn(..) | Enum(..) | Struct(..) | Union(..) | Trait(..) => { - self.stack.pop(); - }, - _ => (), + if is_item_interesting(item) { + self.stack.pop(); } } @@ -149,11 +130,11 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf { if_chain! { if let ImplItemKind::Fn(FnSig { decl, .. }, ..) = impl_item.kind; if let Some(&mut StackItem::Check { - impl_trait_ref_def_id: Some(def_id), + impl_id, ref mut types_to_skip, .. }) = self.stack.last_mut(); - if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(def_id); + if let Some(impl_trait_ref) = cx.tcx.impl_trait_ref(impl_id); then { // `self_ty` is the semantic self type of `impl for `. This cannot be // `Self`. @@ -201,52 +182,40 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf { } } - fn check_body(&mut self, cx: &LateContext<'tcx>, body: &'tcx hir::Body<'_>) { + fn check_body(&mut self, _: &LateContext<'_>, _: &hir::Body<'_>) { // `hir_ty_to_ty` cannot be called in `Body`s or it will panic (sometimes). But in bodies // we can use `cx.typeck_results.node_type(..)` to get the `ty::Ty` from a `hir::Ty`. // However the `node_type()` method can *only* be called in bodies. - // - // This method implementation determines which types should get linted in a `Body` and - // which shouldn't, with a visitor. We could directly lint in the visitor, but then we - // could only allow this lint on item scope. And we would have to check if those types are - // already dealt with in `check_ty` anyway. - if let Some(StackItem::Check { - hir_id, - types_to_lint, - types_to_skip, - .. - }) = self.stack.last_mut() - { - let self_ty = ty_from_hir_id(cx, *hir_id); + if let Some(&mut StackItem::Check { ref mut in_body, .. }) = self.stack.last_mut() { + *in_body += 1; + } + } - let mut visitor = LintTyCollector { - cx, - self_ty, - types_to_lint: vec![], - types_to_skip: vec![], - }; - visitor.visit_expr(&body.value); - types_to_lint.extend(visitor.types_to_lint); - types_to_skip.extend(visitor.types_to_skip); + fn check_body_post(&mut self, _: &LateContext<'_>, _: &hir::Body<'_>) { + if let Some(&mut StackItem::Check { ref mut in_body, .. }) = self.stack.last_mut() { + *in_body -= 1; } } fn check_ty(&mut self, cx: &LateContext<'_>, hir_ty: &hir::Ty<'_>) { if_chain! { - if !in_macro(hir_ty.span) && !in_impl(cx, hir_ty); + if !in_macro(hir_ty.span); if meets_msrv(self.msrv.as_ref(), &msrvs::TYPE_ALIAS_ENUM_VARIANTS); - if let Some(StackItem::Check { - hir_id, - types_to_lint, - types_to_skip, + if let Some(&StackItem::Check { + impl_id, + in_body, + ref types_to_skip, .. }) = self.stack.last(); + if let TyKind::Path(QPath::Resolved(_, path)) = hir_ty.kind; + if !matches!(path.res, Res::SelfTy(..) | Res::Def(DefKind::TyParam, _)); if !types_to_skip.contains(&hir_ty.hir_id); - if types_to_lint.contains(&hir_ty.hir_id) - || { - let self_ty = ty_from_hir_id(cx, *hir_id); - should_lint_ty(hir_ty, hir_ty_to_ty(cx.tcx, hir_ty), self_ty) - }; + let ty = if in_body > 0 { + cx.typeck_results().node_type(hir_ty.hir_id) + } else { + hir_ty_to_ty(cx.tcx, hir_ty) + }; + if same_type_and_consts(ty, cx.tcx.type_of(impl_id)); let hir = cx.tcx.hir(); let id = hir.get_parent_node(hir_ty.hir_id); if !hir.opt_span(id).map_or(false, in_macro); @@ -260,8 +229,8 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf { if_chain! { if !in_macro(expr.span); if meets_msrv(self.msrv.as_ref(), &msrvs::TYPE_ALIAS_ENUM_VARIANTS); - if let Some(StackItem::Check { hir_id, .. }) = self.stack.last(); - if cx.typeck_results().expr_ty(expr) == ty_from_hir_id(cx, *hir_id); + if let Some(&StackItem::Check { impl_id, .. }) = self.stack.last(); + if cx.typeck_results().expr_ty(expr) == cx.tcx.type_of(impl_id); then {} else { return; } } match expr.kind { @@ -309,35 +278,6 @@ impl<'tcx> Visitor<'tcx> for SkipTyCollector { } } -struct LintTyCollector<'a, 'tcx> { - cx: &'a LateContext<'tcx>, - self_ty: Ty<'tcx>, - types_to_lint: Vec, - types_to_skip: Vec, -} - -impl<'a, 'tcx> Visitor<'tcx> for LintTyCollector<'a, 'tcx> { - type Map = Map<'tcx>; - - fn visit_ty(&mut self, hir_ty: &'tcx hir::Ty<'_>) { - if_chain! { - if let Some(ty) = self.cx.typeck_results().node_type_opt(hir_ty.hir_id); - if should_lint_ty(hir_ty, ty, self.self_ty); - then { - self.types_to_lint.push(hir_ty.hir_id); - } else { - self.types_to_skip.push(hir_ty.hir_id); - } - } - - walk_ty(self, hir_ty); - } - - fn nested_visit_map(&mut self) -> NestedVisitorMap { - NestedVisitorMap::None - } -} - fn span_lint(cx: &LateContext<'_>, span: Span) { span_lint_and_sugg( cx, @@ -359,36 +299,11 @@ fn lint_path_to_variant(cx: &LateContext<'_>, path: &Path<'_>) { } } -fn ty_from_hir_id<'tcx>(cx: &LateContext<'tcx>, hir_id: HirId) -> Ty<'tcx> { - if let Some(Node::Ty(hir_ty)) = cx.tcx.hir().find(hir_id) { - hir_ty_to_ty(cx.tcx, hir_ty) - } else { - unreachable!("This function should only be called with `HirId`s that are for sure `Node::Ty`") - } -} - -fn in_impl(cx: &LateContext<'tcx>, hir_ty: &hir::Ty<'_>) -> bool { - let map = cx.tcx.hir(); - let parent = map.get_parent_node(hir_ty.hir_id); - if_chain! { - if let Some(Node::Item(item)) = map.find(parent); - if let ItemKind::Impl { .. } = item.kind; - then { - true - } else { - false - } - } -} - -fn should_lint_ty(hir_ty: &hir::Ty<'_>, ty: Ty<'_>, self_ty: Ty<'_>) -> bool { - if_chain! { - if same_type_and_consts(ty, self_ty); - if let TyKind::Path(QPath::Resolved(_, path)) = hir_ty.kind; - then { - !matches!(path.res, Res::SelfTy(..) | Res::Def(DefKind::TyParam, _)) - } else { - false - } - } +fn is_item_interesting(item: &Item<'_>) -> bool { + #[allow(clippy::enum_glob_use)] + use rustc_hir::ItemKind::*; + matches!( + item.kind, + Impl { .. } | Static(..) | Const(..) | Fn(..) | Enum(..) | Struct(..) | Union(..) | Trait(..) + ) }