Fix clippy

clippy_lints/src/derive.rs

@@ -386,7 +386,8 @@ fn check_unsafe_derive_deserialize<'tcx>(
         && cx
             .tcx
             .inherent_impls(def.did())
-            .iter()
+            .into_iter()
+            .flatten()
             .map(|imp_did| cx.tcx.hir().expect_item(imp_did.expect_local()))
             .any(|imp| has_unsafe(cx, imp))
     {

clippy_lints/src/inherent_impl.rs

@@ -53,9 +53,10 @@ impl<'tcx> LateLintPass<'tcx> for MultipleInherentImpl {
         // List of spans to lint. (lint_span, first_span)
         let mut lint_spans = Vec::new();
 
+        let Ok(impls) = cx.tcx.crate_inherent_impls(()) else { return };
         let inherent_impls = cx
             .tcx
-            .with_stable_hashing_context(|hcx| cx.tcx.crate_inherent_impls(()).inherent_impls.to_sorted(&hcx, true));
+            .with_stable_hashing_context(|hcx| impls.inherent_impls.to_sorted(&hcx, true));
 
         for (_, impl_ids) in inherent_impls.into_iter().filter(|(&id, impls)| {
             impls.len() > 1

clippy_lints/src/iter_without_into_iter.rs

@@ -139,7 +139,7 @@ fn deref_chain<'cx, 'tcx>(cx: &'cx LateContext<'tcx>, ty: Ty<'tcx>) -> impl Iter
 
 fn adt_has_inherent_method(cx: &LateContext<'_>, ty: Ty<'_>, method_name: Symbol) -> bool {
     if let Some(ty_did) = ty.ty_adt_def().map(ty::AdtDef::did) {
-        cx.tcx.inherent_impls(ty_did).iter().any(|&did| {
+        cx.tcx.inherent_impls(ty_did).into_iter().flatten().any(|&did| {
             cx.tcx
                 .associated_items(did)
                 .filter_by_name_unhygienic(method_name)

clippy_lints/src/len_zero.rs

@@ -441,7 +441,8 @@ fn check_for_is_empty(
     let is_empty = cx
         .tcx
         .inherent_impls(impl_ty)
-        .iter()
+        .into_iter()
+        .flatten()
         .flat_map(|&id| cx.tcx.associated_items(id).filter_by_name_unhygienic(is_empty))
         .find(|item| item.kind == AssocKind::Fn);
 
@@ -605,7 +606,7 @@ fn has_is_empty(cx: &LateContext<'_>, expr: &Expr<'_>) -> bool {
     /// Checks the inherent impl's items for an `is_empty(self)` method.
     fn has_is_empty_impl(cx: &LateContext<'_>, id: DefId) -> bool {
         let is_empty = sym!(is_empty);
-        cx.tcx.inherent_impls(id).iter().any(|imp| {
+        cx.tcx.inherent_impls(id).into_iter().flatten().any(|imp| {
             cx.tcx
                 .associated_items(*imp)
                 .filter_by_name_unhygienic(is_empty)

clippy_lints/src/methods/or_fun_call.rs

@@ -73,7 +73,8 @@ pub(super) fn check<'tcx>(
         let has_suggested_method = receiver_ty.ty_adt_def().is_some_and(|adt_def| {
             cx.tcx
                 .inherent_impls(adt_def.did())
-                .iter()
+                .into_iter()
+                .flatten()
                 .flat_map(|impl_id| cx.tcx.associated_items(impl_id).filter_by_name_unhygienic(sugg))
                 .any(|assoc| {
                     assoc.fn_has_self_parameter

clippy_utils/src/lib.rs

@@ -534,10 +534,11 @@ fn find_primitive_impls<'tcx>(tcx: TyCtxt<'tcx>, name: &str) -> impl Iterator<It
         "u128" => SimplifiedType::Uint(UintTy::U128),
         "f32" => SimplifiedType::Float(FloatTy::F32),
         "f64" => SimplifiedType::Float(FloatTy::F64),
-        _ => return [].iter().copied(),
+        #[allow(trivial_casts)]
+        _ => return Result::<_, rustc_errors::ErrorGuaranteed>::Ok(&[] as &[_]).into_iter().flatten().copied(),
     };
 
-    tcx.incoherent_impls(ty).iter().copied()
+    tcx.incoherent_impls(ty).into_iter().flatten().copied()
 }
 
 fn non_local_item_children_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: Symbol) -> Vec<Res> {
@@ -663,7 +664,8 @@ pub fn def_path_res(cx: &LateContext<'_>, path: &[&str]) -> Vec<Res> {
                 // `impl S { ... }`
                 let inherent_impl_children = tcx
                     .inherent_impls(def_id)
-                    .iter()
+                    .into_iter()
+                    .flatten()
                     .flat_map(|&impl_def_id| item_children_by_name(tcx, impl_def_id, segment));
 
                 let direct_children = item_children_by_name(tcx, def_id, segment);