Introduce trait_item_of

Author: camsteffen

clippy_lints/src/functions/renamed_function_params.rs

@@ -1,7 +1,6 @@
 use clippy_utils::diagnostics::span_lint_and_then;
 use rustc_errors::{Applicability, MultiSpan};
-use rustc_hir::def_id::{DefId, DefIdSet};
-use rustc_hir::hir_id::OwnerId;
+use rustc_hir::def_id::DefIdSet;
 use rustc_hir::{Impl, ImplItem, ImplItemKind, ItemKind, Node, TraitRef};
 use rustc_lint::LateContext;
 use rustc_span::Span;
@@ -19,7 +18,7 @@ pub(super) fn check_impl_item(cx: &LateContext<'_>, item: &ImplItem<'_>, ignored
             of_trait: Some(of_trait),
             ..
         }) = &parent_item.kind
-        && let Some(did) = trait_item_def_id_of_impl(cx, item.owner_id)
+        && let Some(did) = cx.tcx.trait_item_of(item.owner_id)
         && !is_from_ignored_trait(&of_trait.trait_ref, ignored_traits)
     {
         let mut param_idents_iter = cx.tcx.hir_body_param_idents(body_id);
@@ -87,11 +86,6 @@ impl RenamedFnArgs {
     }
 }
 
-/// Get the [`trait_item_def_id`](ImplItemRef::trait_item_def_id) of a relevant impl item.
-fn trait_item_def_id_of_impl(cx: &LateContext<'_>, target: OwnerId) -> Option<DefId> {
-    cx.tcx.associated_item(target).trait_item_def_id
-}
-
 fn is_from_ignored_trait(of_trait: &TraitRef<'_>, ignored_traits: &DefIdSet) -> bool {
     of_trait
         .trait_def_id()

clippy_lints/src/only_used_in_recursion.rs

@@ -248,7 +248,7 @@ impl<'tcx> LateLintPass<'tcx> for OnlyUsedInRecursion {
                         .tcx
                         .impl_trait_ref(item.owner_id)
                         .map(EarlyBinder::instantiate_identity)
-                    && let Some(trait_item_id) = cx.tcx.associated_item(owner_id).trait_item_def_id
+                    && let Some(trait_item_id) = cx.tcx.trait_item_of(owner_id)
                 {
                     (
                         trait_item_id,

clippy_lints/src/use_self.rs

@@ -151,8 +151,7 @@ impl<'tcx> LateLintPass<'tcx> for UseSelf {
             // trait, not in the impl of the trait.
             let trait_method = cx
                 .tcx
-                .associated_item(impl_item.owner_id)
-                .trait_item_def_id
+                .trait_item_of(impl_item.owner_id)
                 .expect("impl method matches a trait method");
             let trait_method_sig = cx.tcx.fn_sig(trait_method).instantiate_identity();
             let trait_method_sig = cx.tcx.instantiate_bound_regions_with_erased(trait_method_sig);