100 lines
2.9 KiB
Rust
100 lines
2.9 KiB
Rust
use rustc::lint::{LateContext, LateLintPass, LintArray, LintPass};
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use rustc::hir::*;
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use rustc::hir::intravisit::{walk_path, NestedVisitorMap, Visitor};
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use utils::{in_macro, span_lint_and_then};
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use syntax::ast::NodeId;
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use syntax_pos::symbol::keywords::SelfType;
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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
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/// 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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"Unnecessary structure name repetition 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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const SEGMENTS_MSG: &str = "segments should be composed of at least 1 element";
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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 in_macro(item.span) {
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return;
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}
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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 parameters = &item_path.segments.last().expect(SEGMENTS_MSG).parameters;
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let should_check = if let Some(ref params) = *parameters {
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!params.parenthesized && params.lifetimes.len() == 0
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} else {
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true
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};
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if should_check {
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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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}
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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 && path.segments.last().expect(SEGMENTS_MSG).name != SelfType.name() {
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span_lint_and_then(self.cx, USE_SELF, path.span, "unnecessary structure name repetition", |db| {
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db.span_suggestion(path.span, "use the applicable keyword", "Self".to_owned());
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});
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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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