diff --git a/clippy_lints/src/derive.rs b/clippy_lints/src/derive.rs
index 636698e96f6..649c480fb92 100644
--- a/clippy_lints/src/derive.rs
+++ b/clippy_lints/src/derive.rs
@@ -386,7 +386,6 @@ fn has_unsafe<'tcx>(cx: &LateContext<'tcx>, item: &'tcx Item<'_>) -> bool {
             .tcx
             .inherent_impls(def.did())
             .into_iter()
-            .flatten()
             .map(|imp_did| cx.tcx.hir().expect_item(imp_did.expect_local()))
             .any(|imp| has_unsafe(cx, imp))
     {
diff --git a/clippy_lints/src/inherent_impl.rs b/clippy_lints/src/inherent_impl.rs
index d39f910f993..309d2dfb28b 100644
--- a/clippy_lints/src/inherent_impl.rs
+++ b/clippy_lints/src/inherent_impl.rs
@@ -51,9 +51,7 @@ fn check_crate_post(&mut self, cx: &LateContext<'tcx>) {
         // 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 (impls, _) = cx.tcx.crate_inherent_impls(());
 
         for (&id, impl_ids) in &impls.inherent_impls {
             if impl_ids.len() < 2
diff --git a/clippy_lints/src/len_zero.rs b/clippy_lints/src/len_zero.rs
index 0bc7fc2dd9d..16f86b18e2e 100644
--- a/clippy_lints/src/len_zero.rs
+++ b/clippy_lints/src/len_zero.rs
@@ -448,7 +448,6 @@ fn check_for_is_empty(
         .tcx
         .inherent_impls(impl_ty)
         .into_iter()
-        .flatten()
         .flat_map(|&id| cx.tcx.associated_items(id).filter_by_name_unhygienic(is_empty))
         .find(|item| item.kind == AssocKind::Fn);
 
@@ -616,7 +615,7 @@ fn is_is_empty(cx: &LateContext<'_>, item: &ty::AssocItem) -> 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).into_iter().flatten().any(|imp| {
+        cx.tcx.inherent_impls(id).into_iter().any(|imp| {
             cx.tcx
                 .associated_items(*imp)
                 .filter_by_name_unhygienic(is_empty)
diff --git a/clippy_lints/src/methods/or_fun_call.rs b/clippy_lints/src/methods/or_fun_call.rs
index e4326cb958e..af71799f0a7 100644
--- a/clippy_lints/src/methods/or_fun_call.rs
+++ b/clippy_lints/src/methods/or_fun_call.rs
@@ -78,7 +78,6 @@ fn check_unwrap_or_default(
             cx.tcx
                 .inherent_impls(adt_def.did())
                 .into_iter()
-                .flatten()
                 .flat_map(|impl_id| cx.tcx.associated_items(impl_id).filter_by_name_unhygienic(sugg))
                 .find_map(|assoc| {
                     if assoc.fn_has_self_parameter
diff --git a/clippy_utils/src/lib.rs b/clippy_utils/src/lib.rs
index 0d0d6219c5e..aed0bc565d8 100644
--- a/clippy_utils/src/lib.rs
+++ b/clippy_utils/src/lib.rs
@@ -589,14 +589,11 @@ fn find_primitive_impls<'tcx>(tcx: TyCtxt<'tcx>, name: &str) -> impl Iterator<It
         "f32" => SimplifiedType::Float(FloatTy::F32),
         "f64" => SimplifiedType::Float(FloatTy::F64),
         _ => {
-            return Result::<&[_], rustc_errors::ErrorGuaranteed>::Ok(&[])
-                .into_iter()
-                .flatten()
-                .copied();
+            return [].iter().copied();
         },
     };
 
-    tcx.incoherent_impls(ty).into_iter().flatten().copied()
+    tcx.incoherent_impls(ty).into_iter().copied()
 }
 
 fn non_local_item_children_by_name(tcx: TyCtxt<'_>, def_id: DefId, name: Symbol) -> Vec<Res> {
@@ -721,7 +718,6 @@ fn find_crates(tcx: TyCtxt<'_>, name: Symbol) -> impl Iterator<Item = DefId> + '
                 let inherent_impl_children = tcx
                     .inherent_impls(def_id)
                     .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);
diff --git a/clippy_utils/src/ty.rs b/clippy_utils/src/ty.rs
index 585134209ca..22aaaa1b734 100644
--- a/clippy_utils/src/ty.rs
+++ b/clippy_utils/src/ty.rs
@@ -1316,7 +1316,7 @@ pub fn deref_chain<'cx, 'tcx>(cx: &'cx LateContext<'tcx>, ty: Ty<'tcx>) -> impl
 /// If you need this, you should wrap this call in `clippy_utils::ty::deref_chain().any(...)`.
 pub fn get_adt_inherent_method<'a>(cx: &'a LateContext<'_>, ty: Ty<'_>, method_name: Symbol) -> Option<&'a AssocItem> {
     if let Some(ty_did) = ty.ty_adt_def().map(AdtDef::did) {
-        cx.tcx.inherent_impls(ty_did).into_iter().flatten().find_map(|&did| {
+        cx.tcx.inherent_impls(ty_did).into_iter().find_map(|&did| {
             cx.tcx
                 .associated_items(did)
                 .filter_by_name_unhygienic(method_name)