use if_chain::if_chain;
-use rustc::hir::map::Map;
-use rustc_hir::def::Res;
-use rustc_hir::intravisit::{walk_path, NestedVisitorMap, Visitor};
-use rustc_hir::{AssocItemKind, HirId, ImplItem, ImplItemKind, ImplItemRef, ItemKind, Path};
+use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_lint_pass, declare_tool_lint};
use crate::utils::span_lint_and_help;
+use crate::utils::visitors::LocalUsedVisitor;
declare_clippy_lint! {
/// **What it does:** Checks methods that contain a `self` argument but don't use it
declare_lint_pass!(UnusedSelf => [UNUSED_SELF]);
-impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UnusedSelf {
- fn check_impl_item(&mut self, cx: &LateContext<'a, 'tcx>, impl_item: &ImplItem<'_>) {
+impl<'tcx> LateLintPass<'tcx> for UnusedSelf {
+ fn check_impl_item(&mut self, cx: &LateContext<'tcx>, impl_item: &ImplItem<'_>) {
if impl_item.span.from_expansion() {
return;
}
- let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id);
- let item = cx.tcx.hir().expect_item(parent);
- if let ItemKind::Impl {
- of_trait: None,
- items: impl_item_refs,
- ..
- } = item.kind
- {
- for impl_item_ref in impl_item_refs {
- if_chain! {
- if let ImplItemRef {
- kind: AssocItemKind::Method { has_self: true },
- ..
- } = impl_item_ref;
- if let ImplItemKind::Fn(_, body_id) = &impl_item.kind;
- let body = cx.tcx.hir().body(*body_id);
- if !body.params.is_empty();
- then {
- let self_param = &body.params[0];
- let self_hir_id = self_param.pat.hir_id;
- let mut visitor = UnusedSelfVisitor {
- cx,
- uses_self: false,
- self_hir_id: &self_hir_id,
- };
- visitor.visit_body(body);
- if !visitor.uses_self {
- span_lint_and_help(
- cx,
- UNUSED_SELF,
- self_param.span,
- "unused `self` argument",
- "consider refactoring to a associated function",
- );
- return;
- }
- }
+ let parent = cx.tcx.hir().get_parent_item(impl_item.hir_id());
+ let parent_item = cx.tcx.hir().expect_item(parent);
+ let assoc_item = cx.tcx.associated_item(impl_item.def_id);
+ if_chain! {
+ if let ItemKind::Impl(Impl { of_trait: None, .. }) = parent_item.kind;
+ if assoc_item.fn_has_self_parameter;
+ if let ImplItemKind::Fn(.., body_id) = &impl_item.kind;
+ let body = cx.tcx.hir().body(*body_id);
+ if !body.params.is_empty();
+ then {
+ let self_param = &body.params[0];
+ let self_hir_id = self_param.pat.hir_id;
+ if !LocalUsedVisitor::new(cx, self_hir_id).check_body(body) {
+ span_lint_and_help(
+ cx,
+ UNUSED_SELF,
+ self_param.span,
+ "unused `self` argument",
+ None,
+ "consider refactoring to a associated function",
+ );
+ return;
}
}
- };
- }
-}
-
-struct UnusedSelfVisitor<'a, 'tcx> {
- cx: &'a LateContext<'a, 'tcx>,
- uses_self: bool,
- self_hir_id: &'a HirId,
-}
-
-impl<'a, 'tcx> Visitor<'tcx> for UnusedSelfVisitor<'a, 'tcx> {
- type Map = Map<'tcx>;
-
- fn visit_path(&mut self, path: &'tcx Path<'_>, _id: HirId) {
- if self.uses_self {
- // This function already uses `self`
- return;
- }
- if let Res::Local(hir_id) = &path.res {
- self.uses_self = self.self_hir_id == hir_id
}
- walk_path(self, path);
- }
-
- fn nested_visit_map(&mut self) -> NestedVisitorMap<Self::Map> {
- NestedVisitorMap::OnlyBodies(self.cx.tcx.hir())
}
}