101 lines
3.2 KiB
Rust
101 lines
3.2 KiB
Rust
use clippy_utils::diagnostics::span_lint_and_help;
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use clippy_utils::is_lint_allowed;
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use clippy_utils::macros::span_is_local;
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use rustc_hir::def_id::DefIdMap;
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use rustc_hir::{Impl, Item, ItemKind};
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use rustc_lint::{LateContext, LateLintPass};
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use rustc_middle::ty::AssocItem;
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use rustc_session::declare_lint_pass;
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declare_clippy_lint! {
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/// ### What it does
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/// Checks if a provided method is used implicitly by a trait
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/// implementation. A usage example would be a wrapper where every method
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/// should perform some operation before delegating to the inner type's
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/// implementation.
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///
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/// This lint should typically be enabled on a specific trait `impl` item
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/// rather than globally.
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///
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/// ### Why is this bad?
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/// Indicates that a method is missing.
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///
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/// ### Example
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/// ```no_run
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/// trait Trait {
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/// fn required();
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///
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/// fn provided() {}
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/// }
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///
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/// # struct Type;
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/// #[warn(clippy::missing_trait_methods)]
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/// impl Trait for Type {
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/// fn required() { /* ... */ }
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/// }
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/// ```
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/// Use instead:
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/// ```no_run
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/// trait Trait {
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/// fn required();
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///
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/// fn provided() {}
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/// }
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///
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/// # struct Type;
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/// #[warn(clippy::missing_trait_methods)]
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/// impl Trait for Type {
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/// fn required() { /* ... */ }
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///
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/// fn provided() { /* ... */ }
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/// }
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/// ```
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#[clippy::version = "1.66.0"]
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pub MISSING_TRAIT_METHODS,
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restriction,
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"trait implementation uses default provided method"
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}
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declare_lint_pass!(MissingTraitMethods => [MISSING_TRAIT_METHODS]);
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impl<'tcx> LateLintPass<'tcx> for MissingTraitMethods {
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fn check_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx Item<'tcx>) {
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if !is_lint_allowed(cx, MISSING_TRAIT_METHODS, item.hir_id())
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&& span_is_local(item.span)
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&& let ItemKind::Impl(Impl {
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items,
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of_trait: Some(trait_ref),
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..
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}) = item.kind
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&& let Some(trait_id) = trait_ref.trait_def_id()
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{
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let mut provided: DefIdMap<&AssocItem> = cx
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.tcx
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.provided_trait_methods(trait_id)
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.map(|assoc| (assoc.def_id, assoc))
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.collect();
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for impl_item in *items {
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if let Some(def_id) = impl_item.trait_item_def_id {
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provided.remove(&def_id);
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}
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}
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cx.tcx.with_stable_hashing_context(|hcx| {
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for assoc in provided.values_sorted(&hcx, true) {
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let source_map = cx.tcx.sess.source_map();
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let definition_span = source_map.guess_head_span(cx.tcx.def_span(assoc.def_id));
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span_lint_and_help(
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cx,
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MISSING_TRAIT_METHODS,
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source_map.guess_head_span(item.span),
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&format!("missing trait method provided by default: `{}`", assoc.name),
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Some(definition_span),
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"implement the method",
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);
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}
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});
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}
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}
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}
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