91 lines
2.3 KiB
Rust
91 lines
2.3 KiB
Rust
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use rustc::lint::{LintArray, LateLintPass, LateContext, LintPass};
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use rustc::hir::*;
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use rustc::hir::intravisit::{Visitor, walk_path, NestedVisitorMap};
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use utils::span_lint;
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use syntax::ast::NodeId;
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/// **What it does:** Checks for unnecessary repetition of structure name when a
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/// replacement with `Self` is applicable.
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///
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/// **Why is this bad?** Unnecessary repetition. Mixed use of `Self` and struct name
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/// feels inconsistent.
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///
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/// **Known problems:** None.
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///
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/// **Example:**
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/// ```rust
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/// struct Foo {}
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/// impl Foo {
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/// fn new() -> Foo {
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/// Foo {}
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/// }
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/// }
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/// ```
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/// could be
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/// ```
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/// struct Foo {}
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/// impl Foo {
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/// fn new() -> Self {
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/// Self {}
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/// }
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/// }
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/// ```
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declare_lint! {
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pub USE_SELF,
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Allow,
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"Repetitive struct name usage whereas `Self` is applicable"
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}
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#[derive(Copy, Clone, Default)]
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pub struct UseSelf;
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impl LintPass for UseSelf {
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fn get_lints(&self) -> LintArray {
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lint_array!(USE_SELF)
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}
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}
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impl<'a, 'tcx> LateLintPass<'a, 'tcx> for UseSelf {
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fn check_item(&mut self, cx: &LateContext<'a, 'tcx>, item: &'tcx Item) {
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if_let_chain!([
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let ItemImpl(.., ref item_type, ref refs) = item.node,
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let Ty_::TyPath(QPath::Resolved(_, ref item_path)) = item_type.node,
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], {
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let visitor = &mut UseSelfVisitor {
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item_path: item_path,
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cx: cx,
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};
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for impl_item_ref in refs {
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visitor.visit_impl_item(cx.tcx.hir.impl_item(impl_item_ref.id));
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}
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})
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}
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}
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struct UseSelfVisitor<'a, 'tcx: 'a> {
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item_path: &'a Path,
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cx: &'a LateContext<'a, 'tcx>,
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}
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impl<'a, 'tcx> Visitor<'tcx> for UseSelfVisitor<'a, 'tcx> {
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fn visit_path(&mut self, path: &'tcx Path, _id: NodeId) {
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if self.item_path.def == path.def &&
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path.segments
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.last()
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.expect("segments should be composed of at least 1 elemnt")
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.name
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.as_str() != "Self" {
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span_lint(self.cx,
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USE_SELF,
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path.span,
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"repetitive struct name usage. Use `Self` instead.");
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}
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walk_path(self, path);
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}
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fn nested_visit_map<'this>(&'this mut self) -> NestedVisitorMap<'this, 'tcx> {
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NestedVisitorMap::OnlyBodies(&self.cx.tcx.hir)
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}
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}
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