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 clippy_utils::{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,
+ intravisit::{walk_inf, walk_ty, Visitor},
+ Expr, ExprKind, FnRetTy, FnSig, GenericArg, HirId, Impl, ImplItemKind, Item, ItemKind, Pat, PatKind, Path, QPath,
+ TyKind,
};
-use rustc_lint::{LateContext, LateLintPass, LintContext};
-use rustc_middle::hir::map::Map;
-use rustc_middle::ty::{AssocKind, Ty};
+use rustc_lint::{LateContext, LateLintPass};
use rustc_semver::RustcVersion;
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::Span;
use rustc_typeck::hir_ty_to_ty;
declare_clippy_lint! {
- /// **What it does:** Checks for unnecessary repetition of structure name when a
+ /// ### What it does
+ /// Checks for unnecessary repetition of structure name when a
/// replacement with `Self` is applicable.
///
- /// **Why is this bad?** Unnecessary repetition. Mixed use of `Self` and struct
+ /// ### Why is this bad?
+ /// Unnecessary repetition. Mixed use of `Self` and struct
/// name
/// feels inconsistent.
///
- /// **Known problems:**
+ /// ### Known problems
/// - Unaddressed false negative in fn bodies of trait implementations
- /// - False positive with assotiated types in traits (#4140)
- ///
- /// **Example:**
+ /// - False positive with associated types in traits (#4140)
///
+ /// ### Example
/// ```rust
- /// struct Foo {}
+ /// struct Foo;
/// impl Foo {
/// fn new() -> Foo {
/// Foo {}
/// ```
/// could be
/// ```rust
- /// struct Foo {}
+ /// struct Foo;
/// impl Foo {
/// fn new() -> Self {
/// Self {}
/// }
/// }
/// ```
+ #[clippy::version = "pre 1.29.0"]
pub USE_SELF,
nursery,
"unnecessary structure name repetition whereas `Self` is applicable"
#[derive(Debug)]
enum StackItem {
Check {
- hir_id: HirId,
- impl_trait_ref_def_id: Option<LocalDefId>,
- types_to_skip: Vec<HirId>,
- types_to_lint: Vec<HirId>,
+ impl_id: LocalDefId,
+ in_body: u32,
+ types_to_skip: FxHashSet<HirId>,
},
NoCheck,
}
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<'_>) {
- 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 <..>`
+ fn check_item(&mut self, _cx: &LateContext<'_>, item: &Item<'_>) {
+ if matches!(item.kind, ItemKind::OpaqueTy(_)) {
+ // skip over `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
// 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
let stack_item = if_chain! {
- if let ItemKind::Impl(Impl { self_ty, ref of_trait, .. }) = item.kind;
+ 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 {
- let impl_trait_ref_def_id = of_trait.as_ref().map(|_| cx.tcx.hir().local_def_id(item.hir_id()));
StackItem::Check {
- hir_id: self_ty.hir_id,
- impl_trait_ref_def_id,
- types_to_lint: Vec::new(),
- types_to_skip: Vec::new(),
+ impl_id: item.def_id,
+ in_body: 0,
+ types_to_skip: std::iter::once(self_ty.hir_id).collect(),
}
} else {
StackItem::NoCheck
}
fn check_item_post(&mut self, _: &LateContext<'_>, item: &Item<'_>) {
- if is_item_interesting(item) {
+ if !matches!(item.kind, ItemKind::OpaqueTy(_)) {
self.stack.pop();
}
}
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 <trait> for <type>`. This cannot be
// `Self`.
// trait, not in the impl of the trait.
let trait_method = cx
.tcx
- .associated_items(impl_trait_ref.def_id)
- .find_by_name_and_kind(cx.tcx, impl_item.ident, AssocKind::Fn, impl_trait_ref.def_id)
+ .associated_item(impl_item.def_id)
+ .trait_item_def_id
.expect("impl method matches a trait method");
- let trait_method_sig = cx.tcx.fn_sig(trait_method.def_id);
+ let trait_method_sig = cx.tcx.fn_sig(trait_method);
let trait_method_sig = cx.tcx.erase_late_bound_regions(trait_method_sig);
// `impl_inputs_outputs` is an iterator over the types (`hir::Ty`) declared in the
}
}
- 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 = in_body.saturating_add(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 = in_body.saturating_sub(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 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 !hir_ty.span.from_expansion();
+ if meets_msrv(self.msrv, msrvs::TYPE_ALIAS_ENUM_VARIANTS);
+ 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);
+ // prevents false positive on `#[derive(serde::Deserialize)]`
+ if !hir.span(hir.get_parent_node(hir_ty.hir_id)).in_derive_expansion();
then {
span_lint(cx, hir_ty.span);
}
fn check_expr(&mut self, cx: &LateContext<'_>, expr: &Expr<'_>) {
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 !expr.span.from_expansion();
+ if meets_msrv(self.msrv, msrvs::TYPE_ALIAS_ENUM_VARIANTS);
+ 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 {
ExprKind::Struct(QPath::Resolved(_, path), ..) => match path.res {
- Res::SelfTy(..) => (),
+ Res::SelfTy { .. } => (),
Res::Def(DefKind::Variant, _) => lint_path_to_variant(cx, path),
_ => span_lint(cx, path.span),
},
}
}
+ fn check_pat(&mut self, cx: &LateContext<'_>, pat: &Pat<'_>) {
+ if_chain! {
+ if !pat.span.from_expansion();
+ if meets_msrv(self.msrv, msrvs::TYPE_ALIAS_ENUM_VARIANTS);
+ if let Some(&StackItem::Check { impl_id, .. }) = self.stack.last();
+ // get the path from the pattern
+ if let PatKind::Path(QPath::Resolved(_, path))
+ | PatKind::TupleStruct(QPath::Resolved(_, path), _, _)
+ | PatKind::Struct(QPath::Resolved(_, path), _, _) = pat.kind;
+ if cx.typeck_results().pat_ty(pat) == cx.tcx.type_of(impl_id);
+ then {
+ match path.res {
+ Res::Def(DefKind::Ctor(ctor_of, _), ..) => match ctor_of {
+ CtorOf::Variant => lint_path_to_variant(cx, path),
+ CtorOf::Struct => span_lint(cx, path.span),
+ },
+ Res::Def(DefKind::Variant, ..) => lint_path_to_variant(cx, path),
+ Res::Def(DefKind::Struct, ..) => span_lint(cx, path.span),
+ _ => ()
+ }
+ }
+ }
+ }
+
extract_msrv_attr!(LateContext);
}
}
impl<'tcx> Visitor<'tcx> for SkipTyCollector {
- type Map = Map<'tcx>;
+ fn visit_infer(&mut self, inf: &hir::InferArg) {
+ self.types_to_skip.push(inf.hir_id);
+ walk_inf(self, inf);
+ }
fn visit_ty(&mut self, hir_ty: &hir::Ty<'_>) {
self.types_to_skip.push(hir_ty.hir_id);
walk_ty(self, hir_ty);
}
-
- fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
- NestedVisitorMap::None
- }
-}
-
-struct LintTyCollector<'a, 'tcx> {
- cx: &'a LateContext<'tcx>,
- self_ty: Ty<'tcx>,
- types_to_lint: Vec<HirId>,
- types_to_skip: Vec<HirId>,
-}
-
-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<Self::Map> {
- NestedVisitorMap::None
- }
}
fn span_lint(cx: &LateContext<'_>, span: Span) {
span_lint(cx, span);
}
}
-
-fn is_item_interesting(item: &Item<'_>) -> bool {
- use rustc_hir::ItemKind::{Const, Enum, Fn, Impl, Static, Struct, Trait, Union};
- matches!(
- item.kind,
- Impl { .. } | Static(..) | Const(..) | Fn(..) | Enum(..) | Struct(..) | Union(..) | Trait(..)
- )
-}
-
-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
- }
- }
-}