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Remove a visitor from use_self
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camsteffen committed Jun 28, 2021
1 parent 1b97c9b commit 0e2119c
Showing 1 changed file with 22 additions and 75 deletions.
97 changes: 22 additions & 75 deletions clippy_lints/src/use_self.rs
Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,7 @@ use rustc_hir::{
};
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;
Expand Down Expand Up @@ -75,8 +75,8 @@ impl UseSelf {
enum StackItem {
Check {
impl_id: LocalDefId,
in_body: u32,
types_to_skip: FxHashSet<HirId>,
types_to_lint: Vec<HirId>,
},
NoCheck,
}
Expand Down Expand Up @@ -108,7 +108,7 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
then {
StackItem::Check {
impl_id: item.def_id,
types_to_lint: Vec::new(),
in_body: 0,
types_to_skip: std::iter::once(self_ty.hir_id).collect(),
}
} else {
Expand Down Expand Up @@ -182,52 +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 {
impl_id,
types_to_lint,
types_to_skip,
..
}) = self.stack.last_mut()
{
let self_ty = cx.tcx.type_of(*impl_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);
if meets_msrv(self.msrv.as_ref(), &msrvs::TYPE_ALIAS_ENUM_VARIANTS);
if let Some(StackItem::Check {
if let Some(&StackItem::Check {
impl_id,
types_to_lint,
types_to_skip,
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 = cx.tcx.type_of(*impl_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);
Expand Down Expand Up @@ -290,35 +278,6 @@ impl<'tcx> Visitor<'tcx> for SkipTyCollector {
}
}

struct LintTyCollector<'a, 'tcx> {
cx: &'a LateContext<'tcx>,
self_ty: Ty<'tcx>,
types_to_lint: Vec<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_and_sugg(
cx,
Expand Down Expand Up @@ -348,15 +307,3 @@ fn is_item_interesting(item: &Item<'_>) -> bool {
Impl { .. } | Static(..) | Const(..) | Fn(..) | Enum(..) | Struct(..) | Union(..) | Trait(..)
)
}

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
}
}
}

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