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Auto merge of #8252 - dswij:8229, r=xFrednet

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cover trait for `trait_duplication_in_bounds`

closes #8229

changelog: [`trait_duplication_in_bounds`] covers trait functions with `Self` bounds
This commit is contained in:
bors 2022-01-10 10:31:59 +00:00
commit 88cfd70100
3 changed files with 139 additions and 3 deletions
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55
clippy_lints/src/trait_bounds.rs
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@ -3,10 +3,14 @@ use clippy_utils::source::{snippet, snippet_with_applicability};
use clippy_utils::{SpanlessEq, SpanlessHash};
use core::hash::{Hash, Hasher};
use if_chain::if_chain;
use rustc_data_structures::fx::FxHashMap;
use rustc_data_structures::fx::{FxHashMap, FxHashSet};
use rustc_data_structures::unhash::UnhashMap;
use rustc_errors::Applicability;
use rustc_hir::{def::Res, GenericBound, Generics, ParamName, Path, QPath, Ty, TyKind, WherePredicate};
use rustc_hir::def::Res;
use rustc_hir::{
GenericBound, Generics, Item, ItemKind, Node, ParamName, Path, PathSegment, QPath, TraitItem, Ty, TyKind,
WherePredicate,
};
use rustc_lint::{LateContext, LateLintPass};
use rustc_session::{declare_tool_lint, impl_lint_pass};
use rustc_span::Span;
@ -84,6 +88,53 @@ impl<'tcx> LateLintPass<'tcx> for TraitBounds {
self.check_type_repetition(cx, gen);
check_trait_bound_duplication(cx, gen);
}
fn check_trait_item(&mut self, cx: &LateContext<'tcx>, item: &'tcx TraitItem<'tcx>) {
let Generics { where_clause, .. } = &item.generics;
let mut self_bounds_set = FxHashSet::default();
for predicate in where_clause.predicates {
if_chain! {
if let WherePredicate::BoundPredicate(ref bound_predicate) = predicate;
if !bound_predicate.span.from_expansion();
if let TyKind::Path(QPath::Resolved(_, Path { segments, .. })) = bound_predicate.bounded_ty.kind;
if let Some(PathSegment { res: Some(Res::SelfTy(Some(def_id), _)), .. }) = segments.first();
if let Some(
Node::Item(
Item {
kind: ItemKind::Trait(_, _, _, self_bounds, _),
.. }
)
) = cx.tcx.hir().get_if_local(*def_id);
then {
if self_bounds_set.is_empty() {
for bound in self_bounds.iter() {
let Some((self_res, _)) = get_trait_res_span_from_bound(bound) else { continue };
self_bounds_set.insert(self_res);
}
}
bound_predicate
.bounds
.iter()
.filter_map(get_trait_res_span_from_bound)
.for_each(|(trait_item_res, span)| {
if self_bounds_set.get(&trait_item_res).is_some() {
span_lint_and_help(
cx,
TRAIT_DUPLICATION_IN_BOUNDS,
span,
"this trait bound is already specified in trait declaration",
None,
"consider removing this trait bound",
);
}
});
}
}
}
}
}
fn get_trait_res_span_from_bound(bound: &GenericBound<'_>) -> Option<(Res, Span)> {