diff --git a/src/contexts.h b/src/contexts.h
index ae0e348d77..7856e8c5ec 100644
--- a/src/contexts.h
+++ b/src/contexts.h
@@ -436,11 +436,6 @@ class ScriptContextTable : public FixedArray {
 
 class Context : public FixedArray, public NeverReadOnlySpaceObject {
  public:
-  // Use the mixin methods over the HeapObject methods.
-  // TODO(v8:7786) Remove once the HeapObject methods are gone.
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Conversions.
   static inline Context* cast(Object* context);
 
diff --git a/src/feedback-vector.h b/src/feedback-vector.h
index 5fc03d19a0..edfb029ac0 100644
--- a/src/feedback-vector.h
+++ b/src/feedback-vector.h
@@ -147,11 +147,6 @@ class FeedbackMetadata;
 // metadata.
 class FeedbackVector : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  // Use the mixin methods over the HeapObject methods.
-  // TODO(v8:7786) Remove once the HeapObject methods are gone.
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Casting.
   static inline FeedbackVector* cast(Object* obj);
 
diff --git a/src/objects.h b/src/objects.h
index 4049f9402e..05fbfc8d63 100644
--- a/src/objects.h
+++ b/src/objects.h
@@ -1997,11 +1997,6 @@ class PropertyArray : public HeapObject {
 // JSObject and JSProxy.
 class JSReceiver : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  // Use the mixin methods over the HeapObject methods.
-  // TODO(v8:7786) Remove once the HeapObject methods are gone.
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Returns true if there is no slow (ie, dictionary) backing store.
   inline bool HasFastProperties() const;
 
@@ -4016,9 +4011,6 @@ class AccessorPair: public Struct {
 
 class StackFrameInfo : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   DECL_INT_ACCESSORS(line_number)
   DECL_INT_ACCESSORS(column_number)
   DECL_INT_ACCESSORS(script_id)
diff --git a/src/objects/allocation-site.h b/src/objects/allocation-site.h
index 55d0c034f4..ca4bb2920c 100644
--- a/src/objects/allocation-site.h
+++ b/src/objects/allocation-site.h
@@ -29,11 +29,6 @@ class AllocationSite : public Struct, public NeverReadOnlySpaceObject {
     kLastPretenureDecisionValue = kZombie
   };
 
-  // Use the mixin methods over the HeapObject methods.
-  // TODO(v8:7786) Remove once the HeapObject methods are gone.
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   const char* PretenureDecisionName(PretenureDecision decision);
 
   // Contains either a Smi-encoded bitfield or a boilerplate. If it's a Smi the
diff --git a/src/objects/bigint.cc b/src/objects/bigint.cc
index 48de2ce192..dcf99e2f29 100644
--- a/src/objects/bigint.cc
+++ b/src/objects/bigint.cc
@@ -36,9 +36,6 @@ namespace internal {
 class MutableBigInt : public FreshlyAllocatedBigInt,
                       public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Bottleneck for converting MutableBigInts to BigInts.
   static MaybeHandle<BigInt> MakeImmutable(MaybeHandle<MutableBigInt> maybe);
   static Handle<BigInt> MakeImmutable(Handle<MutableBigInt> result);
diff --git a/src/objects/code.h b/src/objects/code.h
index b8bfebe47a..2879e20c0f 100644
--- a/src/objects/code.h
+++ b/src/objects/code.h
@@ -27,8 +27,6 @@ class Register;
 // Code describes objects with on-the-fly generated machine code.
 class Code : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
   // Opaque data type for encapsulating code flags like kind, inline
   // cache state, and arguments count.
   typedef uint32_t Flags;
@@ -459,9 +457,6 @@ class Code : public HeapObject, public NeverReadOnlySpaceObject {
 // field {Code::code_data_container} itself is immutable.
 class CodeDataContainer : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   DECL_ACCESSORS(next_code_link, Object)
   DECL_INT_ACCESSORS(kind_specific_flags)
 
@@ -501,9 +496,6 @@ class CodeDataContainer : public HeapObject, public NeverReadOnlySpaceObject {
 
 class AbstractCode : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // All code kinds and INTERPRETED_FUNCTION.
   enum Kind {
 #define DEFINE_CODE_KIND_ENUM(name) name,
diff --git a/src/objects/compilation-cache.h b/src/objects/compilation-cache.h
index 76deeb9684..45590cade6 100644
--- a/src/objects/compilation-cache.h
+++ b/src/objects/compilation-cache.h
@@ -69,9 +69,6 @@ class CompilationCacheTable
     : public HashTable<CompilationCacheTable, CompilationCacheShape>,
       public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Find cached value for a string key, otherwise return null.
   Handle<Object> Lookup(Handle<String> src, Handle<SharedFunctionInfo> shared,
                         LanguageMode language_mode);
diff --git a/src/objects/debug-objects.h b/src/objects/debug-objects.h
index 3b94a4e46e..84f244c758 100644
--- a/src/objects/debug-objects.h
+++ b/src/objects/debug-objects.h
@@ -21,9 +21,6 @@ class BytecodeArray;
 // debugged.
 class DebugInfo : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   enum Flag {
     kNone = 0,
     kHasBreakInfo = 1 << 0,
diff --git a/src/objects/map.h b/src/objects/map.h
index ea40ef8c09..066ce2b026 100644
--- a/src/objects/map.h
+++ b/src/objects/map.h
@@ -971,9 +971,6 @@ class Map : public HeapObject {
 class NormalizedMapCache : public WeakFixedArray,
                            public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   static Handle<NormalizedMapCache> New(Isolate* isolate);
 
   V8_WARN_UNUSED_RESULT MaybeHandle<Map> Get(Handle<Map> fast_map,
diff --git a/src/objects/module.h b/src/objects/module.h
index 0cdb5a9433..776c3628af 100644
--- a/src/objects/module.h
+++ b/src/objects/module.h
@@ -27,9 +27,6 @@ class Zone;
 // The runtime representation of an ECMAScript module.
 class Module : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   DECL_CAST(Module)
   DECL_VERIFIER(Module)
   DECL_PRINTER(Module)
diff --git a/src/objects/script.h b/src/objects/script.h
index 3420b71754..bd789ba2ff 100644
--- a/src/objects/script.h
+++ b/src/objects/script.h
@@ -17,9 +17,6 @@ namespace internal {
 // Script describes a script which has been added to the VM.
 class Script : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   // Script types.
   enum Type {
     TYPE_NATIVE = 0,
diff --git a/src/objects/shared-function-info.h b/src/objects/shared-function-info.h
index f9a207fa08..9e3c69147b 100644
--- a/src/objects/shared-function-info.h
+++ b/src/objects/shared-function-info.h
@@ -179,9 +179,6 @@ class InterpreterData : public Struct {
 // shared by multiple instances of the function.
 class SharedFunctionInfo : public HeapObject, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   static constexpr Object* const kNoSharedNameSentinel = Smi::kZero;
 
   // [name]: Returns shared name if it exists or an empty string otherwise.
diff --git a/src/objects/templates.h b/src/objects/templates.h
index 6a229d847b..24cbd18bd2 100644
--- a/src/objects/templates.h
+++ b/src/objects/templates.h
@@ -15,9 +15,6 @@ namespace internal {
 
 class TemplateInfo : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   DECL_ACCESSORS(tag, Object)
   DECL_ACCESSORS(serial_number, Object)
   DECL_INT_ACCESSORS(number_of_properties)
diff --git a/src/wasm/wasm-objects.h b/src/wasm/wasm-objects.h
index 2adf6b3d6e..3872957189 100644
--- a/src/wasm/wasm-objects.h
+++ b/src/wasm/wasm-objects.h
@@ -542,9 +542,6 @@ class WasmExportedFunctionData : public Struct {
 
 class WasmDebugInfo : public Struct, public NeverReadOnlySpaceObject {
  public:
-  using NeverReadOnlySpaceObject::GetHeap;
-  using NeverReadOnlySpaceObject::GetIsolate;
-
   DECL_ACCESSORS(wasm_instance, WasmInstanceObject)
   DECL_ACCESSORS(interpreter_handle, Object);
   DECL_ACCESSORS(interpreted_functions, Object);