diff --git a/upb/message/array.c b/upb/message/array.c
index ba3f743010..d7858d3b22 100644
--- a/upb/message/array.c
+++ b/upb/message/array.c
@@ -28,13 +28,13 @@ const void* upb_Array_DataPtr(const upb_Array* arr) {
 
 void* upb_Array_MutableDataPtr(upb_Array* arr) { return _upb_array_ptr(arr); }
 
-size_t upb_Array_Size(const upb_Array* arr) { return arr->size; }
+size_t upb_Array_Size(const upb_Array* arr) { return arr->UPB_PRIVATE(size); }
 
 upb_MessageValue upb_Array_Get(const upb_Array* arr, size_t i) {
   upb_MessageValue ret;
   const char* data = _upb_array_constptr(arr);
   const int lg2 = UPB_PRIVATE(_upb_Array_ElemSizeLg2)(arr);
-  UPB_ASSERT(i < arr->size);
+  UPB_ASSERT(i < arr->UPB_PRIVATE(size));
   memcpy(&ret, data + (i << lg2), 1 << lg2);
   return ret;
 }
@@ -42,16 +42,16 @@ upb_MessageValue upb_Array_Get(const upb_Array* arr, size_t i) {
 void upb_Array_Set(upb_Array* arr, size_t i, upb_MessageValue val) {
   char* data = _upb_array_ptr(arr);
   const int lg2 = UPB_PRIVATE(_upb_Array_ElemSizeLg2)(arr);
-  UPB_ASSERT(i < arr->size);
+  UPB_ASSERT(i < arr->UPB_PRIVATE(size));
   memcpy(data + (i << lg2), &val, 1 << lg2);
 }
 
 bool upb_Array_Append(upb_Array* arr, upb_MessageValue val, upb_Arena* arena) {
   UPB_ASSERT(arena);
-  if (!_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!_upb_Array_ResizeUninitialized(arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  upb_Array_Set(arr, arr->size - 1, val);
+  upb_Array_Set(arr, arr->UPB_PRIVATE(size) - 1, val);
   return true;
 }
 
@@ -65,10 +65,11 @@ void upb_Array_Move(upb_Array* arr, size_t dst_idx, size_t src_idx,
 bool upb_Array_Insert(upb_Array* arr, size_t i, size_t count,
                       upb_Arena* arena) {
   UPB_ASSERT(arena);
-  UPB_ASSERT(i <= arr->size);
-  UPB_ASSERT(count + arr->size >= count);
-  const size_t oldsize = arr->size;
-  if (!_upb_Array_ResizeUninitialized(arr, arr->size + count, arena)) {
+  UPB_ASSERT(i <= arr->UPB_PRIVATE(size));
+  UPB_ASSERT(count + arr->UPB_PRIVATE(size) >= count);
+  const size_t oldsize = arr->UPB_PRIVATE(size);
+  if (!_upb_Array_ResizeUninitialized(arr, arr->UPB_PRIVATE(size) + count,
+                                      arena)) {
     return false;
   }
   upb_Array_Move(arr, i + count, i, oldsize - i);
@@ -82,17 +83,17 @@ bool upb_Array_Insert(upb_Array* arr, size_t i, size_t count,
 void upb_Array_Delete(upb_Array* arr, size_t i, size_t count) {
   const size_t end = i + count;
   UPB_ASSERT(i <= end);
-  UPB_ASSERT(end <= arr->size);
-  upb_Array_Move(arr, i, end, arr->size - end);
-  arr->size -= count;
+  UPB_ASSERT(end <= arr->UPB_PRIVATE(size));
+  upb_Array_Move(arr, i, end, arr->UPB_PRIVATE(size) - end);
+  arr->UPB_PRIVATE(size) -= count;
 }
 
 bool upb_Array_Resize(upb_Array* arr, size_t size, upb_Arena* arena) {
-  const size_t oldsize = arr->size;
+  const size_t oldsize = arr->UPB_PRIVATE(size);
   if (UPB_UNLIKELY(!_upb_Array_ResizeUninitialized(arr, size, arena))) {
     return false;
   }
-  const size_t newsize = arr->size;
+  const size_t newsize = arr->UPB_PRIVATE(size);
   if (newsize > oldsize) {
     const int lg2 = UPB_PRIVATE(_upb_Array_ElemSizeLg2)(arr);
     char* data = _upb_array_ptr(arr);
diff --git a/upb/message/copy.c b/upb/message/copy.c
index b5a634df6c..7ad30ccc02 100644
--- a/upb/message/copy.c
+++ b/upb/message/copy.c
@@ -142,7 +142,7 @@ static upb_Map* upb_Message_Map_DeepClone(const upb_Map* map,
 
 upb_Array* upb_Array_DeepClone(const upb_Array* array, upb_CType value_type,
                                const upb_MiniTable* sub, upb_Arena* arena) {
-  size_t size = array->size;
+  size_t size = array->UPB_PRIVATE(size);
   upb_Array* cloned_array =
       UPB_PRIVATE(_upb_Array_New)(arena, size, upb_CType_SizeLg2(value_type));
   if (!cloned_array) {
diff --git a/upb/message/internal/array.h b/upb/message/internal/array.h
index 68aedf3377..4d03e4b978 100644
--- a/upb/message/internal/array.h
+++ b/upb/message/internal/array.h
@@ -35,7 +35,7 @@ struct upb_Array {
   // Bit #2 contains the frozen/immutable flag (currently unimplemented).
   uintptr_t data;
 
-  size_t size;                   // The number of elements in the array.
+  size_t UPB_ONLYBITS(size);     // The number of elements in the array.
   size_t UPB_PRIVATE(capacity);  // Allocated storage. Measured in elements.
 };
 
@@ -73,7 +73,7 @@ UPB_INLINE upb_Array* UPB_PRIVATE(_upb_Array_New)(upb_Arena* arena,
   if (!array) return NULL;
   UPB_PRIVATE(_upb_Array_SetTaggedPtr)
   (array, UPB_PTR_AT(array, array_size, void), elem_size_lg2);
-  array->size = 0;
+  array->UPB_ONLYBITS(size) = 0;
   array->UPB_PRIVATE(capacity) = init_capacity;
   return array;
 }
@@ -92,9 +92,10 @@ UPB_INLINE bool UPB_PRIVATE(_upb_Array_Reserve)(upb_Array* array, size_t size,
 // Resize without initializing new elements.
 UPB_INLINE bool _upb_Array_ResizeUninitialized(upb_Array* array, size_t size,
                                                upb_Arena* arena) {
-  UPB_ASSERT(size <= array->size || arena);  // Allow NULL arena when shrinking.
+  UPB_ASSERT(size <= array->UPB_ONLYBITS(size) ||
+             arena);  // Allow NULL arena when shrinking.
   if (!UPB_PRIVATE(_upb_Array_Reserve)(array, size, arena)) return false;
-  array->size = size;
+  array->UPB_ONLYBITS(size) = size;
   return true;
 }
 
@@ -104,7 +105,7 @@ UPB_INLINE bool _upb_Array_ResizeUninitialized(upb_Array* array, size_t size,
 UPB_INLINE void UPB_PRIVATE(_upb_Array_Set)(upb_Array* array, size_t i,
                                             const void* data,
                                             size_t elem_size) {
-  UPB_ASSERT(i < array->size);
+  UPB_ASSERT(i < array->UPB_ONLYBITS(size));
   UPB_ASSERT(elem_size == 1U << UPB_PRIVATE(_upb_Array_ElemSizeLg2)(array));
   char* arr_data = (char*)_upb_array_ptr(array);
   memcpy(arr_data + (i * elem_size), data, elem_size);
diff --git a/upb/message/promote.c b/upb/message/promote.c
index e33af5bec6..4fd9e676a3 100644
--- a/upb/message/promote.c
+++ b/upb/message/promote.c
@@ -196,7 +196,7 @@ upb_DecodeStatus upb_Array_PromoteMessages(upb_Array* arr,
                                            int decode_options,
                                            upb_Arena* arena) {
   void** data = _upb_array_ptr(arr);
-  size_t size = arr->size;
+  size_t size = arr->UPB_PRIVATE(size);
   for (size_t i = 0; i < size; i++) {
     upb_TaggedMessagePtr tagged;
     memcpy(&tagged, &data[i], sizeof(tagged));
diff --git a/upb/reflection/stage0/google/protobuf/descriptor.upb.h b/upb/reflection/stage0/google/protobuf/descriptor.upb.h
index 76ac5db89a..2ac29d6610 100644
--- a/upb/reflection/stage0/google/protobuf/descriptor.upb.h
+++ b/upb/reflection/stage0/google/protobuf/descriptor.upb.h
@@ -276,7 +276,7 @@ UPB_INLINE const google_protobuf_FileDescriptorProto* const* google_protobuf_Fil
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorSet_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FileDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -287,7 +287,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorSet_file_upb_array(co
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorSet_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -296,7 +296,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorSet_file_mutable_upb_array(
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -305,7 +305,7 @@ UPB_INLINE google_protobuf_FileDescriptorProto** google_protobuf_FileDescriptorS
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorSet_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FileDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -319,12 +319,14 @@ UPB_INLINE google_protobuf_FileDescriptorProto** google_protobuf_FileDescriptorS
 UPB_INLINE struct google_protobuf_FileDescriptorProto* google_protobuf_FileDescriptorSet_add_file(google_protobuf_FileDescriptorSet* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorSet_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FileDescriptorProto* sub = (struct google_protobuf_FileDescriptorProto*)_upb_Message_New(google__protobuf__FileDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -401,7 +403,7 @@ UPB_INLINE upb_StringView const* google_protobuf_FileDescriptorProto_dependency(
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 3);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -412,7 +414,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_dependency_upb_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 3);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -421,7 +423,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_dependency_mutable_up
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -433,7 +435,7 @@ UPB_INLINE const google_protobuf_DescriptorProto* const* google_protobuf_FileDes
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_DescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -444,7 +446,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_message_type_up
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -453,7 +455,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_message_type_mutable_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -465,7 +467,7 @@ UPB_INLINE const google_protobuf_EnumDescriptorProto* const* google_protobuf_Fil
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_EnumDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -476,7 +478,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_enum_type_upb_a
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -485,7 +487,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_enum_type_mutable_upb
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -497,7 +499,7 @@ UPB_INLINE const google_protobuf_ServiceDescriptorProto* const* google_protobuf_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_ServiceDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -508,7 +510,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_service_upb_arr
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -517,7 +519,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_service_mutable_upb_a
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -529,7 +531,7 @@ UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_Fi
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 7);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -540,7 +542,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_extension_upb_a
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 7);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -549,7 +551,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_extension_mutable_upb
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -591,7 +593,7 @@ UPB_INLINE int32_t const* google_protobuf_FileDescriptorProto_public_dependency(
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 10);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -602,7 +604,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_public_dependen
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 10);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -611,7 +613,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_public_dependency_mut
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -623,7 +625,7 @@ UPB_INLINE int32_t const* google_protobuf_FileDescriptorProto_weak_dependency(co
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 11);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -634,7 +636,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileDescriptorProto_weak_dependency
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 11);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -643,7 +645,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileDescriptorProto_weak_dependency_mutab
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -690,7 +692,7 @@ UPB_INLINE upb_StringView* google_protobuf_FileDescriptorProto_mutable_dependenc
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 3);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -704,17 +706,19 @@ UPB_INLINE upb_StringView* google_protobuf_FileDescriptorProto_resize_dependency
 UPB_INLINE bool google_protobuf_FileDescriptorProto_add_dependency(google_protobuf_FileDescriptorProto* msg, upb_StringView val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 3);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_FileDescriptorProto_mutable_message_type(google_protobuf_FileDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_DescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -728,19 +732,21 @@ UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_FileDescriptorProto
 UPB_INLINE struct google_protobuf_DescriptorProto* google_protobuf_FileDescriptorProto_add_message_type(google_protobuf_FileDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_DescriptorProto* sub = (struct google_protobuf_DescriptorProto*)_upb_Message_New(google__protobuf__DescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_FileDescriptorProto_mutable_enum_type(google_protobuf_FileDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_EnumDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -754,19 +760,21 @@ UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_FileDescriptorP
 UPB_INLINE struct google_protobuf_EnumDescriptorProto* google_protobuf_FileDescriptorProto_add_enum_type(google_protobuf_FileDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_EnumDescriptorProto* sub = (struct google_protobuf_EnumDescriptorProto*)_upb_Message_New(google__protobuf__EnumDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_ServiceDescriptorProto** google_protobuf_FileDescriptorProto_mutable_service(google_protobuf_FileDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 6);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_ServiceDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -780,19 +788,21 @@ UPB_INLINE google_protobuf_ServiceDescriptorProto** google_protobuf_FileDescript
 UPB_INLINE struct google_protobuf_ServiceDescriptorProto* google_protobuf_FileDescriptorProto_add_service(google_protobuf_FileDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 6);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_ServiceDescriptorProto* sub = (struct google_protobuf_ServiceDescriptorProto*)_upb_Message_New(google__protobuf__ServiceDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_FileDescriptorProto_mutable_extension(google_protobuf_FileDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 7);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FieldDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -806,12 +816,14 @@ UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_FileDescriptor
 UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_FileDescriptorProto_add_extension(google_protobuf_FileDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 7);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)_upb_Message_New(google__protobuf__FieldDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_FileDescriptorProto_set_options(google_protobuf_FileDescriptorProto *msg, google_protobuf_FileOptions* value) {
@@ -842,7 +854,7 @@ UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_mutable_public_dependenc
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 10);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -856,17 +868,19 @@ UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_resize_public_dependency
 UPB_INLINE bool google_protobuf_FileDescriptorProto_add_public_dependency(google_protobuf_FileDescriptorProto* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 10);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_mutable_weak_dependency(google_protobuf_FileDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 11);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -880,10 +894,12 @@ UPB_INLINE int32_t* google_protobuf_FileDescriptorProto_resize_weak_dependency(g
 UPB_INLINE bool google_protobuf_FileDescriptorProto_add_weak_dependency(google_protobuf_FileDescriptorProto* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileDescriptorProto_msg_init(), 11);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE void google_protobuf_FileDescriptorProto_set_syntax(google_protobuf_FileDescriptorProto *msg, upb_StringView value) {
@@ -953,7 +969,7 @@ UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_De
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -964,7 +980,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_field_upb_array(con
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -973,7 +989,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_field_mutable_upb_array(c
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -985,7 +1001,7 @@ UPB_INLINE const google_protobuf_DescriptorProto* const* google_protobuf_Descrip
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 3);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_DescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -996,7 +1012,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_nested_type_upb_arr
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 3);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1005,7 +1021,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_nested_type_mutable_upb_a
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1017,7 +1033,7 @@ UPB_INLINE const google_protobuf_EnumDescriptorProto* const* google_protobuf_Des
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_EnumDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1028,7 +1044,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_enum_type_upb_array
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1037,7 +1053,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_enum_type_mutable_upb_arr
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1049,7 +1065,7 @@ UPB_INLINE const google_protobuf_DescriptorProto_ExtensionRange* const* google_p
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_DescriptorProto_ExtensionRange* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1060,7 +1076,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_extension_range_upb
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1069,7 +1085,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_extension_range_mutable_u
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1081,7 +1097,7 @@ UPB_INLINE const google_protobuf_FieldDescriptorProto* const* google_protobuf_De
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FieldDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1092,7 +1108,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_extension_upb_array
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1101,7 +1117,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_extension_mutable_upb_arr
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1128,7 +1144,7 @@ UPB_INLINE const google_protobuf_OneofDescriptorProto* const* google_protobuf_De
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 8);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_OneofDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1139,7 +1155,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_oneof_decl_upb_arra
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 8);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1148,7 +1164,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_oneof_decl_mutable_upb_ar
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1160,7 +1176,7 @@ UPB_INLINE const google_protobuf_DescriptorProto_ReservedRange* const* google_pr
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 9);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_DescriptorProto_ReservedRange* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1171,7 +1187,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_reserved_range_upb_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 9);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1180,7 +1196,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_reserved_range_mutable_up
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1192,7 +1208,7 @@ UPB_INLINE upb_StringView const* google_protobuf_DescriptorProto_reserved_name(c
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 10);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1203,7 +1219,7 @@ UPB_INLINE const upb_Array* _google_protobuf_DescriptorProto_reserved_name_upb_a
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 10);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1212,7 +1228,7 @@ UPB_INLINE upb_Array* _google_protobuf_DescriptorProto_reserved_name_mutable_upb
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1225,7 +1241,7 @@ UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProt
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FieldDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1239,19 +1255,21 @@ UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProt
 UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_DescriptorProto_add_field(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)_upb_Message_New(google__protobuf__FieldDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_DescriptorProto_mutable_nested_type(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 3);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_DescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1265,19 +1283,21 @@ UPB_INLINE google_protobuf_DescriptorProto** google_protobuf_DescriptorProto_res
 UPB_INLINE struct google_protobuf_DescriptorProto* google_protobuf_DescriptorProto_add_nested_type(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 3);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_DescriptorProto* sub = (struct google_protobuf_DescriptorProto*)_upb_Message_New(google__protobuf__DescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_DescriptorProto_mutable_enum_type(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_EnumDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1291,19 +1311,21 @@ UPB_INLINE google_protobuf_EnumDescriptorProto** google_protobuf_DescriptorProto
 UPB_INLINE struct google_protobuf_EnumDescriptorProto* google_protobuf_DescriptorProto_add_enum_type(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_EnumDescriptorProto* sub = (struct google_protobuf_EnumDescriptorProto*)_upb_Message_New(google__protobuf__EnumDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange** google_protobuf_DescriptorProto_mutable_extension_range(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_DescriptorProto_ExtensionRange**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1317,19 +1339,21 @@ UPB_INLINE google_protobuf_DescriptorProto_ExtensionRange** google_protobuf_Desc
 UPB_INLINE struct google_protobuf_DescriptorProto_ExtensionRange* google_protobuf_DescriptorProto_add_extension_range(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_DescriptorProto_ExtensionRange* sub = (struct google_protobuf_DescriptorProto_ExtensionRange*)_upb_Message_New(google__protobuf__DescriptorProto__ExtensionRange_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProto_mutable_extension(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 6);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FieldDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1343,12 +1367,14 @@ UPB_INLINE google_protobuf_FieldDescriptorProto** google_protobuf_DescriptorProt
 UPB_INLINE struct google_protobuf_FieldDescriptorProto* google_protobuf_DescriptorProto_add_extension(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 6);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FieldDescriptorProto* sub = (struct google_protobuf_FieldDescriptorProto*)_upb_Message_New(google__protobuf__FieldDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_DescriptorProto_set_options(google_protobuf_DescriptorProto *msg, google_protobuf_MessageOptions* value) {
@@ -1367,7 +1393,7 @@ UPB_INLINE google_protobuf_OneofDescriptorProto** google_protobuf_DescriptorProt
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 8);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_OneofDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1381,19 +1407,21 @@ UPB_INLINE google_protobuf_OneofDescriptorProto** google_protobuf_DescriptorProt
 UPB_INLINE struct google_protobuf_OneofDescriptorProto* google_protobuf_DescriptorProto_add_oneof_decl(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 8);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_OneofDescriptorProto* sub = (struct google_protobuf_OneofDescriptorProto*)_upb_Message_New(google__protobuf__OneofDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE google_protobuf_DescriptorProto_ReservedRange** google_protobuf_DescriptorProto_mutable_reserved_range(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 9);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_DescriptorProto_ReservedRange**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1407,19 +1435,21 @@ UPB_INLINE google_protobuf_DescriptorProto_ReservedRange** google_protobuf_Descr
 UPB_INLINE struct google_protobuf_DescriptorProto_ReservedRange* google_protobuf_DescriptorProto_add_reserved_range(google_protobuf_DescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 9);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_DescriptorProto_ReservedRange* sub = (struct google_protobuf_DescriptorProto_ReservedRange*)_upb_Message_New(google__protobuf__DescriptorProto__ReservedRange_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE upb_StringView* google_protobuf_DescriptorProto_mutable_reserved_name(google_protobuf_DescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 10);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1433,10 +1463,12 @@ UPB_INLINE upb_StringView* google_protobuf_DescriptorProto_resize_reserved_name(
 UPB_INLINE bool google_protobuf_DescriptorProto_add_reserved_name(google_protobuf_DescriptorProto* msg, upb_StringView val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__DescriptorProto_msg_init(), 10);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 
@@ -1660,7 +1692,7 @@ UPB_INLINE const google_protobuf_ExtensionRangeOptions_Declaration* const* googl
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_ExtensionRangeOptions_Declaration* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1671,7 +1703,7 @@ UPB_INLINE const upb_Array* _google_protobuf_ExtensionRangeOptions_declaration_u
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1680,7 +1712,7 @@ UPB_INLINE upb_Array* _google_protobuf_ExtensionRangeOptions_declaration_mutable
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1722,7 +1754,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Ext
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -1733,7 +1765,7 @@ UPB_INLINE const upb_Array* _google_protobuf_ExtensionRangeOptions_uninterpreted
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1742,7 +1774,7 @@ UPB_INLINE upb_Array* _google_protobuf_ExtensionRangeOptions_uninterpreted_optio
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -1751,7 +1783,7 @@ UPB_INLINE google_protobuf_ExtensionRangeOptions_Declaration** google_protobuf_E
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_ExtensionRangeOptions_Declaration**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1765,12 +1797,14 @@ UPB_INLINE google_protobuf_ExtensionRangeOptions_Declaration** google_protobuf_E
 UPB_INLINE struct google_protobuf_ExtensionRangeOptions_Declaration* google_protobuf_ExtensionRangeOptions_add_declaration(google_protobuf_ExtensionRangeOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_ExtensionRangeOptions_Declaration* sub = (struct google_protobuf_ExtensionRangeOptions_Declaration*)_upb_Message_New(google__protobuf__ExtensionRangeOptions__Declaration_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_ExtensionRangeOptions_set_verification(google_protobuf_ExtensionRangeOptions *msg, int32_t value) {
@@ -1793,7 +1827,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ExtensionRangeO
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -1807,12 +1841,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ExtensionRangeO
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_ExtensionRangeOptions_add_uninterpreted_option(google_protobuf_ExtensionRangeOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ExtensionRangeOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -2343,7 +2379,7 @@ UPB_INLINE const google_protobuf_EnumValueDescriptorProto* const* google_protobu
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_EnumValueDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -2354,7 +2390,7 @@ UPB_INLINE const upb_Array* _google_protobuf_EnumDescriptorProto_value_upb_array
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2363,7 +2399,7 @@ UPB_INLINE upb_Array* _google_protobuf_EnumDescriptorProto_value_mutable_upb_arr
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2390,7 +2426,7 @@ UPB_INLINE const google_protobuf_EnumDescriptorProto_EnumReservedRange* const* g
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_EnumDescriptorProto_EnumReservedRange* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -2401,7 +2437,7 @@ UPB_INLINE const upb_Array* _google_protobuf_EnumDescriptorProto_reserved_range_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 4);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2410,7 +2446,7 @@ UPB_INLINE upb_Array* _google_protobuf_EnumDescriptorProto_reserved_range_mutabl
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2422,7 +2458,7 @@ UPB_INLINE upb_StringView const* google_protobuf_EnumDescriptorProto_reserved_na
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -2433,7 +2469,7 @@ UPB_INLINE const upb_Array* _google_protobuf_EnumDescriptorProto_reserved_name_u
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 5);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2442,7 +2478,7 @@ UPB_INLINE upb_Array* _google_protobuf_EnumDescriptorProto_reserved_name_mutable
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2455,7 +2491,7 @@ UPB_INLINE google_protobuf_EnumValueDescriptorProto** google_protobuf_EnumDescri
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_EnumValueDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -2469,12 +2505,14 @@ UPB_INLINE google_protobuf_EnumValueDescriptorProto** google_protobuf_EnumDescri
 UPB_INLINE struct google_protobuf_EnumValueDescriptorProto* google_protobuf_EnumDescriptorProto_add_value(google_protobuf_EnumDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_EnumValueDescriptorProto* sub = (struct google_protobuf_EnumValueDescriptorProto*)_upb_Message_New(google__protobuf__EnumValueDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_EnumDescriptorProto_set_options(google_protobuf_EnumDescriptorProto *msg, google_protobuf_EnumOptions* value) {
@@ -2493,7 +2531,7 @@ UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange** google_protob
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_EnumDescriptorProto_EnumReservedRange**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -2507,19 +2545,21 @@ UPB_INLINE google_protobuf_EnumDescriptorProto_EnumReservedRange** google_protob
 UPB_INLINE struct google_protobuf_EnumDescriptorProto_EnumReservedRange* google_protobuf_EnumDescriptorProto_add_reserved_range(google_protobuf_EnumDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 4);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_EnumDescriptorProto_EnumReservedRange* sub = (struct google_protobuf_EnumDescriptorProto_EnumReservedRange*)_upb_Message_New(google__protobuf__EnumDescriptorProto__EnumReservedRange_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE upb_StringView* google_protobuf_EnumDescriptorProto_mutable_reserved_name(google_protobuf_EnumDescriptorProto* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -2533,10 +2573,12 @@ UPB_INLINE upb_StringView* google_protobuf_EnumDescriptorProto_resize_reserved_n
 UPB_INLINE bool google_protobuf_EnumDescriptorProto_add_reserved_name(google_protobuf_EnumDescriptorProto* msg, upb_StringView val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumDescriptorProto_msg_init(), 5);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 
@@ -2775,7 +2817,7 @@ UPB_INLINE const google_protobuf_MethodDescriptorProto* const* google_protobuf_S
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceDescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_MethodDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -2786,7 +2828,7 @@ UPB_INLINE const upb_Array* _google_protobuf_ServiceDescriptorProto_method_upb_a
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceDescriptorProto_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2795,7 +2837,7 @@ UPB_INLINE upb_Array* _google_protobuf_ServiceDescriptorProto_method_mutable_upb
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -2823,7 +2865,7 @@ UPB_INLINE google_protobuf_MethodDescriptorProto** google_protobuf_ServiceDescri
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceDescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_MethodDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -2837,12 +2879,14 @@ UPB_INLINE google_protobuf_MethodDescriptorProto** google_protobuf_ServiceDescri
 UPB_INLINE struct google_protobuf_MethodDescriptorProto* google_protobuf_ServiceDescriptorProto_add_method(google_protobuf_ServiceDescriptorProto* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceDescriptorProto_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_MethodDescriptorProto* sub = (struct google_protobuf_MethodDescriptorProto*)_upb_Message_New(google__protobuf__MethodDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_ServiceDescriptorProto_set_options(google_protobuf_ServiceDescriptorProto *msg, google_protobuf_ServiceOptions* value) {
@@ -3375,7 +3419,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Fil
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -3386,7 +3430,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FileOptions_uninterpreted_option_up
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3395,7 +3439,7 @@ UPB_INLINE upb_Array* _google_protobuf_FileOptions_uninterpreted_option_mutable_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3496,7 +3540,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FileOptions_mut
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -3510,12 +3554,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FileOptions_res
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FileOptions_add_uninterpreted_option(google_protobuf_FileOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FileOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -3652,7 +3698,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Mes
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MessageOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -3663,7 +3709,7 @@ UPB_INLINE const upb_Array* _google_protobuf_MessageOptions_uninterpreted_option
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MessageOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3672,7 +3718,7 @@ UPB_INLINE upb_Array* _google_protobuf_MessageOptions_uninterpreted_option_mutab
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3713,7 +3759,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MessageOptions_
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MessageOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -3727,12 +3773,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MessageOptions_
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MessageOptions_add_uninterpreted_option(google_protobuf_MessageOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MessageOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -3914,7 +3962,7 @@ UPB_INLINE int32_t const* google_protobuf_FieldOptions_targets(const google_prot
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 19);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -3925,7 +3973,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FieldOptions_targets_upb_array(cons
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 19);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3934,7 +3982,7 @@ UPB_INLINE upb_Array* _google_protobuf_FieldOptions_targets_mutable_upb_array(co
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3946,7 +3994,7 @@ UPB_INLINE const google_protobuf_FieldOptions_EditionDefault* const* google_prot
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 20);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FieldOptions_EditionDefault* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -3957,7 +4005,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FieldOptions_edition_defaults_upb_a
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 20);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3966,7 +4014,7 @@ UPB_INLINE upb_Array* _google_protobuf_FieldOptions_edition_defaults_mutable_upb
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -3993,7 +4041,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Fie
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4004,7 +4052,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FieldOptions_uninterpreted_option_u
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4013,7 +4061,7 @@ UPB_INLINE upb_Array* _google_protobuf_FieldOptions_uninterpreted_option_mutable
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4058,7 +4106,7 @@ UPB_INLINE int32_t* google_protobuf_FieldOptions_mutable_targets(google_protobuf
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 19);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4072,17 +4120,19 @@ UPB_INLINE int32_t* google_protobuf_FieldOptions_resize_targets(google_protobuf_
 UPB_INLINE bool google_protobuf_FieldOptions_add_targets(google_protobuf_FieldOptions* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 19);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE google_protobuf_FieldOptions_EditionDefault** google_protobuf_FieldOptions_mutable_edition_defaults(google_protobuf_FieldOptions* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 20);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FieldOptions_EditionDefault**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4096,12 +4146,14 @@ UPB_INLINE google_protobuf_FieldOptions_EditionDefault** google_protobuf_FieldOp
 UPB_INLINE struct google_protobuf_FieldOptions_EditionDefault* google_protobuf_FieldOptions_add_edition_defaults(google_protobuf_FieldOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 20);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FieldOptions_EditionDefault* sub = (struct google_protobuf_FieldOptions_EditionDefault*)_upb_Message_New(google__protobuf__FieldOptions__EditionDefault_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_FieldOptions_set_features(google_protobuf_FieldOptions *msg, google_protobuf_FeatureSet* value) {
@@ -4120,7 +4172,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FieldOptions_mu
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4134,12 +4186,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_FieldOptions_re
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_FieldOptions_add_uninterpreted_option(google_protobuf_FieldOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FieldOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -4276,7 +4330,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_One
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__OneofOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4287,7 +4341,7 @@ UPB_INLINE const upb_Array* _google_protobuf_OneofOptions_uninterpreted_option_u
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__OneofOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4296,7 +4350,7 @@ UPB_INLINE upb_Array* _google_protobuf_OneofOptions_uninterpreted_option_mutable
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4317,7 +4371,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_OneofOptions_mu
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__OneofOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4331,12 +4385,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_OneofOptions_re
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_OneofOptions_add_uninterpreted_option(google_protobuf_OneofOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__OneofOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -4443,7 +4499,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Enu
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4454,7 +4510,7 @@ UPB_INLINE const upb_Array* _google_protobuf_EnumOptions_uninterpreted_option_up
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4463,7 +4519,7 @@ UPB_INLINE upb_Array* _google_protobuf_EnumOptions_uninterpreted_option_mutable_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4496,7 +4552,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumOptions_mut
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4510,12 +4566,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumOptions_res
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumOptions_add_uninterpreted_option(google_protobuf_EnumOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -4607,7 +4665,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Enu
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumValueOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4618,7 +4676,7 @@ UPB_INLINE const upb_Array* _google_protobuf_EnumValueOptions_uninterpreted_opti
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumValueOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4627,7 +4685,7 @@ UPB_INLINE upb_Array* _google_protobuf_EnumValueOptions_uninterpreted_option_mut
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4656,7 +4714,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumValueOption
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumValueOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4670,12 +4728,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_EnumValueOption
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_EnumValueOptions_add_uninterpreted_option(google_protobuf_EnumValueOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__EnumValueOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -4752,7 +4812,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Ser
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4763,7 +4823,7 @@ UPB_INLINE const upb_Array* _google_protobuf_ServiceOptions_uninterpreted_option
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4772,7 +4832,7 @@ UPB_INLINE upb_Array* _google_protobuf_ServiceOptions_uninterpreted_option_mutab
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4797,7 +4857,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ServiceOptions_
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4811,12 +4871,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_ServiceOptions_
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_ServiceOptions_add_uninterpreted_option(google_protobuf_ServiceOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__ServiceOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -4908,7 +4970,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption* const* google_protobuf_Met
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MethodOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -4919,7 +4981,7 @@ UPB_INLINE const upb_Array* _google_protobuf_MethodOptions_uninterpreted_option_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MethodOptions_msg_init(), 999);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4928,7 +4990,7 @@ UPB_INLINE upb_Array* _google_protobuf_MethodOptions_uninterpreted_option_mutabl
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -4957,7 +5019,7 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MethodOptions_m
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MethodOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -4971,12 +5033,14 @@ UPB_INLINE google_protobuf_UninterpretedOption** google_protobuf_MethodOptions_r
 UPB_INLINE struct google_protobuf_UninterpretedOption* google_protobuf_MethodOptions_add_uninterpreted_option(google_protobuf_MethodOptions* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__MethodOptions_msg_init(), 999);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption* sub = (struct google_protobuf_UninterpretedOption*)_upb_Message_New(google__protobuf__UninterpretedOption_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -5023,7 +5087,7 @@ UPB_INLINE const google_protobuf_UninterpretedOption_NamePart* const* google_pro
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__UninterpretedOption_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_UninterpretedOption_NamePart* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5034,7 +5098,7 @@ UPB_INLINE const upb_Array* _google_protobuf_UninterpretedOption_name_upb_array(
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__UninterpretedOption_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5043,7 +5107,7 @@ UPB_INLINE upb_Array* _google_protobuf_UninterpretedOption_name_mutable_upb_arra
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5142,7 +5206,7 @@ UPB_INLINE google_protobuf_UninterpretedOption_NamePart** google_protobuf_Uninte
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__UninterpretedOption_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_UninterpretedOption_NamePart**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5156,12 +5220,14 @@ UPB_INLINE google_protobuf_UninterpretedOption_NamePart** google_protobuf_Uninte
 UPB_INLINE struct google_protobuf_UninterpretedOption_NamePart* google_protobuf_UninterpretedOption_add_name(google_protobuf_UninterpretedOption* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__UninterpretedOption_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_UninterpretedOption_NamePart* sub = (struct google_protobuf_UninterpretedOption_NamePart*)_upb_Message_New(google__protobuf__UninterpretedOption__NamePart_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_UninterpretedOption_set_identifier_value(google_protobuf_UninterpretedOption *msg, upb_StringView value) {
@@ -5458,7 +5524,7 @@ UPB_INLINE const google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault* co
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FeatureSetDefaults_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5469,7 +5535,7 @@ UPB_INLINE const upb_Array* _google_protobuf_FeatureSetDefaults_defaults_upb_arr
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FeatureSetDefaults_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5478,7 +5544,7 @@ UPB_INLINE upb_Array* _google_protobuf_FeatureSetDefaults_defaults_mutable_upb_a
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5517,7 +5583,7 @@ UPB_INLINE google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault** google_
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FeatureSetDefaults_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5531,12 +5597,14 @@ UPB_INLINE google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault** google_
 UPB_INLINE struct google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault* google_protobuf_FeatureSetDefaults_add_defaults(google_protobuf_FeatureSetDefaults* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__FeatureSetDefaults_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault* sub = (struct google_protobuf_FeatureSetDefaults_FeatureSetEditionDefault*)_upb_Message_New(google__protobuf__FeatureSetDefaults__FeatureSetEditionDefault_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE void google_protobuf_FeatureSetDefaults_set_minimum_edition(google_protobuf_FeatureSetDefaults *msg, int32_t value) {
@@ -5674,7 +5742,7 @@ UPB_INLINE const google_protobuf_SourceCodeInfo_Location* const* google_protobuf
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_SourceCodeInfo_Location* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5685,7 +5753,7 @@ UPB_INLINE const upb_Array* _google_protobuf_SourceCodeInfo_location_upb_array(c
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5694,7 +5762,7 @@ UPB_INLINE upb_Array* _google_protobuf_SourceCodeInfo_location_mutable_upb_array
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5703,7 +5771,7 @@ UPB_INLINE google_protobuf_SourceCodeInfo_Location** google_protobuf_SourceCodeI
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_SourceCodeInfo_Location**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5717,12 +5785,14 @@ UPB_INLINE google_protobuf_SourceCodeInfo_Location** google_protobuf_SourceCodeI
 UPB_INLINE struct google_protobuf_SourceCodeInfo_Location* google_protobuf_SourceCodeInfo_add_location(google_protobuf_SourceCodeInfo* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_SourceCodeInfo_Location* sub = (struct google_protobuf_SourceCodeInfo_Location*)_upb_Message_New(google__protobuf__SourceCodeInfo__Location_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -5769,7 +5839,7 @@ UPB_INLINE int32_t const* google_protobuf_SourceCodeInfo_Location_path(const goo
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5780,7 +5850,7 @@ UPB_INLINE const upb_Array* _google_protobuf_SourceCodeInfo_Location_path_upb_ar
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5789,7 +5859,7 @@ UPB_INLINE upb_Array* _google_protobuf_SourceCodeInfo_Location_path_mutable_upb_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5801,7 +5871,7 @@ UPB_INLINE int32_t const* google_protobuf_SourceCodeInfo_Location_span(const goo
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5812,7 +5882,7 @@ UPB_INLINE const upb_Array* _google_protobuf_SourceCodeInfo_Location_span_upb_ar
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 2);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5821,7 +5891,7 @@ UPB_INLINE upb_Array* _google_protobuf_SourceCodeInfo_Location_span_mutable_upb_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5863,7 +5933,7 @@ UPB_INLINE upb_StringView const* google_protobuf_SourceCodeInfo_Location_leading
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -5874,7 +5944,7 @@ UPB_INLINE const upb_Array* _google_protobuf_SourceCodeInfo_Location_leading_det
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 6);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5883,7 +5953,7 @@ UPB_INLINE upb_Array* _google_protobuf_SourceCodeInfo_Location_leading_detached_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -5892,7 +5962,7 @@ UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_mutable_path(google_
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5906,17 +5976,19 @@ UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_resize_path(google_p
 UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_path(google_protobuf_SourceCodeInfo_Location* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_mutable_span(google_protobuf_SourceCodeInfo_Location* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 2);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5930,10 +6002,12 @@ UPB_INLINE int32_t* google_protobuf_SourceCodeInfo_Location_resize_span(google_p
 UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_span(google_protobuf_SourceCodeInfo_Location* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 2);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE void google_protobuf_SourceCodeInfo_Location_set_leading_comments(google_protobuf_SourceCodeInfo_Location *msg, upb_StringView value) {
@@ -5948,7 +6022,7 @@ UPB_INLINE upb_StringView* google_protobuf_SourceCodeInfo_Location_mutable_leadi
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 6);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -5962,10 +6036,12 @@ UPB_INLINE upb_StringView* google_protobuf_SourceCodeInfo_Location_resize_leadin
 UPB_INLINE bool google_protobuf_SourceCodeInfo_Location_add_leading_detached_comments(google_protobuf_SourceCodeInfo_Location* msg, upb_StringView val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__SourceCodeInfo__Location_msg_init(), 6);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 
@@ -6012,7 +6088,7 @@ UPB_INLINE const google_protobuf_GeneratedCodeInfo_Annotation* const* google_pro
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_GeneratedCodeInfo_Annotation* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -6023,7 +6099,7 @@ UPB_INLINE const upb_Array* _google_protobuf_GeneratedCodeInfo_annotation_upb_ar
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -6032,7 +6108,7 @@ UPB_INLINE upb_Array* _google_protobuf_GeneratedCodeInfo_annotation_mutable_upb_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -6041,7 +6117,7 @@ UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation** google_protobuf_Genera
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_GeneratedCodeInfo_Annotation**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -6055,12 +6131,14 @@ UPB_INLINE google_protobuf_GeneratedCodeInfo_Annotation** google_protobuf_Genera
 UPB_INLINE struct google_protobuf_GeneratedCodeInfo_Annotation* google_protobuf_GeneratedCodeInfo_add_annotation(google_protobuf_GeneratedCodeInfo* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_GeneratedCodeInfo_Annotation* sub = (struct google_protobuf_GeneratedCodeInfo_Annotation*)_upb_Message_New(google__protobuf__GeneratedCodeInfo__Annotation_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -6107,7 +6185,7 @@ UPB_INLINE int32_t const* google_protobuf_GeneratedCodeInfo_Annotation_path(cons
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo__Annotation_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -6118,7 +6196,7 @@ UPB_INLINE const upb_Array* _google_protobuf_GeneratedCodeInfo_Annotation_path_u
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo__Annotation_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -6127,7 +6205,7 @@ UPB_INLINE upb_Array* _google_protobuf_GeneratedCodeInfo_Annotation_path_mutable
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -6196,7 +6274,7 @@ UPB_INLINE int32_t* google_protobuf_GeneratedCodeInfo_Annotation_mutable_path(go
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo__Annotation_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (int32_t*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -6210,10 +6288,12 @@ UPB_INLINE int32_t* google_protobuf_GeneratedCodeInfo_Annotation_resize_path(goo
 UPB_INLINE bool google_protobuf_GeneratedCodeInfo_Annotation_add_path(google_protobuf_GeneratedCodeInfo_Annotation* msg, int32_t val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__GeneratedCodeInfo__Annotation_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE void google_protobuf_GeneratedCodeInfo_Annotation_set_source_file(google_protobuf_GeneratedCodeInfo_Annotation *msg, upb_StringView value) {
diff --git a/upb/wire/decode.c b/upb/wire/decode.c
index fdd780e198..214fca0798 100644
--- a/upb/wire/decode.c
+++ b/upb/wire/decode.c
@@ -133,9 +133,10 @@ static void _upb_Decoder_VerifyUtf8(upb_Decoder* d, const char* buf, int len) {
 }
 
 static bool _upb_Decoder_Reserve(upb_Decoder* d, upb_Array* arr, size_t elem) {
-  bool need_realloc = arr->UPB_PRIVATE(capacity) - arr->size < elem;
-  if (need_realloc &&
-      !UPB_PRIVATE(_upb_Array_Realloc)(arr, arr->size + elem, &d->arena)) {
+  bool need_realloc =
+      arr->UPB_PRIVATE(capacity) - arr->UPB_PRIVATE(size) < elem;
+  if (need_realloc && !UPB_PRIVATE(_upb_Array_Realloc)(
+                          arr, arr->UPB_PRIVATE(size) + elem, &d->arena)) {
     _upb_Decoder_ErrorJmp(d, kUpb_DecodeStatus_OutOfMemory);
   }
   return need_realloc;
@@ -409,8 +410,8 @@ static const char* _upb_Decoder_DecodeEnumArray(upb_Decoder* d, const char* ptr,
                                                 wireval* val) {
   const upb_MiniTableEnum* e = _upb_MiniTableSubs_EnumByField(subs, field);
   if (!_upb_Decoder_CheckEnum(d, ptr, msg, e, field, val)) return ptr;
-  void* mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->size * 4, void);
-  arr->size++;
+  void* mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) * 4, void);
+  arr->UPB_PRIVATE(size)++;
   memcpy(mem, val, 4);
   return ptr;
 }
@@ -426,8 +427,9 @@ static const char* _upb_Decoder_DecodeFixedPacked(
     _upb_Decoder_ErrorJmp(d, kUpb_DecodeStatus_Malformed);
   }
   _upb_Decoder_Reserve(d, arr, count);
-  void* mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->size << lg2, void);
-  arr->size += count;
+  void* mem =
+      UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) << lg2, void);
+  arr->UPB_PRIVATE(size) += count;
   // Note: if/when the decoder supports multi-buffer input, we will need to
   // handle buffer seams here.
   if (_upb_IsLittleEndian()) {
@@ -457,15 +459,17 @@ static const char* _upb_Decoder_DecodeVarintPacked(
     const upb_MiniTableField* field, int lg2) {
   int scale = 1 << lg2;
   int saved_limit = upb_EpsCopyInputStream_PushLimit(&d->input, ptr, val->size);
-  char* out = UPB_PTR_AT(_upb_array_ptr(arr), arr->size << lg2, void);
+  char* out =
+      UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) << lg2, void);
   while (!_upb_Decoder_IsDone(d, &ptr)) {
     wireval elem;
     ptr = _upb_Decoder_DecodeVarint(d, ptr, &elem.uint64_val);
     _upb_Decoder_Munge(field->UPB_PRIVATE(descriptortype), &elem);
     if (_upb_Decoder_Reserve(d, arr, 1)) {
-      out = UPB_PTR_AT(_upb_array_ptr(arr), arr->size << lg2, void);
+      out =
+          UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) << lg2, void);
     }
-    arr->size++;
+    arr->UPB_PRIVATE(size)++;
     memcpy(out, &elem, scale);
     out += scale;
   }
@@ -480,7 +484,7 @@ static const char* _upb_Decoder_DecodeEnumPacked(
     wireval* val) {
   const upb_MiniTableEnum* e = _upb_MiniTableSubs_EnumByField(subs, field);
   int saved_limit = upb_EpsCopyInputStream_PushLimit(&d->input, ptr, val->size);
-  char* out = UPB_PTR_AT(_upb_array_ptr(arr), arr->size * 4, void);
+  char* out = UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) * 4, void);
   while (!_upb_Decoder_IsDone(d, &ptr)) {
     wireval elem;
     ptr = _upb_Decoder_DecodeVarint(d, ptr, &elem.uint64_val);
@@ -489,9 +493,9 @@ static const char* _upb_Decoder_DecodeEnumPacked(
       continue;
     }
     if (_upb_Decoder_Reserve(d, arr, 1)) {
-      out = UPB_PTR_AT(_upb_array_ptr(arr), arr->size * 4, void);
+      out = UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) * 4, void);
     }
-    arr->size++;
+    arr->UPB_PRIVATE(size)++;
     memcpy(out, &elem, 4);
     out += 4;
   }
@@ -529,8 +533,8 @@ static const char* _upb_Decoder_DecodeToArray(upb_Decoder* d, const char* ptr,
     case kUpb_DecodeOp_Scalar4Byte:
     case kUpb_DecodeOp_Scalar8Byte:
       /* Append scalar value. */
-      mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->size << op, void);
-      arr->size++;
+      mem = UPB_PTR_AT(_upb_array_ptr(arr), arr->UPB_PRIVATE(size) << op, void);
+      arr->UPB_PRIVATE(size)++;
       memcpy(mem, val, 1 << op);
       return ptr;
     case kUpb_DecodeOp_String:
@@ -538,16 +542,18 @@ static const char* _upb_Decoder_DecodeToArray(upb_Decoder* d, const char* ptr,
       /* Fallthrough. */
     case kUpb_DecodeOp_Bytes: {
       /* Append bytes. */
-      upb_StringView* str = (upb_StringView*)_upb_array_ptr(arr) + arr->size;
-      arr->size++;
+      upb_StringView* str =
+          (upb_StringView*)_upb_array_ptr(arr) + arr->UPB_PRIVATE(size);
+      arr->UPB_PRIVATE(size)++;
       return _upb_Decoder_ReadString(d, ptr, val->size, str);
     }
     case kUpb_DecodeOp_SubMessage: {
       /* Append submessage / group. */
       upb_TaggedMessagePtr* target = UPB_PTR_AT(
-          _upb_array_ptr(arr), arr->size * sizeof(void*), upb_TaggedMessagePtr);
+          _upb_array_ptr(arr), arr->UPB_PRIVATE(size) * sizeof(void*),
+          upb_TaggedMessagePtr);
       upb_Message* submsg = _upb_Decoder_NewSubMessage(d, subs, field, target);
-      arr->size++;
+      arr->UPB_PRIVATE(size)++;
       if (UPB_UNLIKELY(field->UPB_PRIVATE(descriptortype) ==
                        kUpb_FieldType_Group)) {
         return _upb_Decoder_DecodeKnownGroup(d, ptr, submsg, subs, field);
diff --git a/upb/wire/decode_fast.c b/upb/wire/decode_fast.c
index 4aebbf1c8d..889bb6432d 100644
--- a/upb/wire/decode_fast.c
+++ b/upb/wire/decode_fast.c
@@ -193,7 +193,7 @@ static bool fastdecode_tagmatch(uint32_t tag, uint64_t data, int tagbytes) {
 UPB_FORCEINLINE
 static void fastdecode_commitarr(void* dst, fastdecode_arr* farr,
                                  int valbytes) {
-  farr->arr->size =
+  farr->arr->UPB_PRIVATE(size) =
       (size_t)((char*)dst - (char*)_upb_array_ptr(farr->arr)) / valbytes;
 }
 
@@ -264,7 +264,7 @@ static void* fastdecode_getfield(upb_Decoder* d, const char* ptr,
       begin = _upb_array_ptr(farr->arr);
       farr->end = begin + (farr->arr->UPB_PRIVATE(capacity) * valbytes);
       *data = _upb_FastDecoder_LoadTag(ptr);
-      return begin + (farr->arr->size * valbytes);
+      return begin + (farr->arr->UPB_PRIVATE(size) * valbytes);
     }
     default:
       UPB_UNREACHABLE();
@@ -552,7 +552,7 @@ TAGBYTES(p)
                                                                             \
   char* dst = _upb_array_ptr(arr);                                          \
   memcpy(dst, ptr, size);                                                   \
-  arr->size = elems;                                                        \
+  arr->UPB_PRIVATE(size) = elems;                                           \
                                                                             \
   ptr += size;                                                              \
   UPB_MUSTTAIL return fastdecode_dispatch(UPB_PARSE_ARGS);
diff --git a/upb/wire/encode.c b/upb/wire/encode.c
index 672f612012..bcc0b6edae 100644
--- a/upb/wire/encode.c
+++ b/upb/wire/encode.c
@@ -181,7 +181,7 @@ static void encode_tag(upb_encstate* e, uint32_t field_number,
 
 static void encode_fixedarray(upb_encstate* e, const upb_Array* arr,
                               size_t elem_size, uint32_t tag) {
-  size_t bytes = arr->size * elem_size;
+  size_t bytes = arr->UPB_PRIVATE(size) * elem_size;
   const char* data = _upb_array_constptr(arr);
   const char* ptr = data + bytes - elem_size;
 
@@ -313,14 +313,14 @@ static void encode_array(upb_encstate* e, const upb_Message* msg,
   bool packed = upb_MiniTableField_IsPacked(f);
   size_t pre_len = e->limit - e->ptr;
 
-  if (arr == NULL || arr->size == 0) {
+  if (arr == NULL || arr->UPB_PRIVATE(size) == 0) {
     return;
   }
 
 #define VARINT_CASE(ctype, encode)                                         \
   {                                                                        \
     const ctype* start = _upb_array_constptr(arr);                         \
-    const ctype* ptr = start + arr->size;                                  \
+    const ctype* ptr = start + arr->UPB_PRIVATE(size);                     \
     uint32_t tag =                                                         \
         packed ? 0 : (f->UPB_PRIVATE(number) << 3) | kUpb_WireType_Varint; \
     do {                                                                   \
@@ -365,7 +365,7 @@ static void encode_array(upb_encstate* e, const upb_Message* msg,
     case kUpb_FieldType_String:
     case kUpb_FieldType_Bytes: {
       const upb_StringView* start = _upb_array_constptr(arr);
-      const upb_StringView* ptr = start + arr->size;
+      const upb_StringView* ptr = start + arr->UPB_PRIVATE(size);
       do {
         ptr--;
         encode_bytes(e, ptr->data, ptr->size);
@@ -376,7 +376,7 @@ static void encode_array(upb_encstate* e, const upb_Message* msg,
     }
     case kUpb_FieldType_Group: {
       const upb_TaggedMessagePtr* start = _upb_array_constptr(arr);
-      const upb_TaggedMessagePtr* ptr = start + arr->size;
+      const upb_TaggedMessagePtr* ptr = start + arr->UPB_PRIVATE(size);
       const upb_MiniTable* subm =
           upb_MiniTableSub_Message(subs[f->UPB_PRIVATE(submsg_index)]);
       if (--e->depth == 0) encode_err(e, kUpb_EncodeStatus_MaxDepthExceeded);
@@ -392,7 +392,7 @@ static void encode_array(upb_encstate* e, const upb_Message* msg,
     }
     case kUpb_FieldType_Message: {
       const upb_TaggedMessagePtr* start = _upb_array_constptr(arr);
-      const upb_TaggedMessagePtr* ptr = start + arr->size;
+      const upb_TaggedMessagePtr* ptr = start + arr->UPB_PRIVATE(size);
       const upb_MiniTable* subm =
           upb_MiniTableSub_Message(subs[f->UPB_PRIVATE(submsg_index)]);
       if (--e->depth == 0) encode_err(e, kUpb_EncodeStatus_MaxDepthExceeded);
diff --git a/upb_generator/protoc-gen-upb.cc b/upb_generator/protoc-gen-upb.cc
index 2d84796561..8a7e213f54 100644
--- a/upb_generator/protoc-gen-upb.cc
+++ b/upb_generator/protoc-gen-upb.cc
@@ -503,7 +503,7 @@ void GenerateRepeatedGetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           const upb_MiniTableField field = $3;
           const upb_Array* arr = upb_Message_GetArray(msg, &field);
           if (arr) {
-            if (size) *size = arr->size;
+            if (size) *size = arr->UPB_PRIVATE(size);
             return ($0 const*)_upb_array_constptr(arr);
           } else {
             if (size) *size = 0;
@@ -528,7 +528,7 @@ void GenerateRepeatedGetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           const upb_MiniTableField field = $3;
           const upb_Array* arr = upb_Message_GetArray(msg, &field);
           if (size) {
-            *size = arr ? arr->size : 0;
+            *size = arr ? arr->UPB_PRIVATE(size) : 0;
           }
           return arr;
         }
@@ -537,7 +537,7 @@ void GenerateRepeatedGetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           upb_Array* arr = upb_Message_GetOrCreateMutableArray(
               (upb_Message*)msg, &field, arena);
           if (size) {
-            *size = arr ? arr->size : 0;
+            *size = arr ? arr->UPB_PRIVATE(size) : 0;
           }
           return arr;
         }
@@ -649,7 +649,7 @@ void GenerateRepeatedSetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           upb_MiniTableField field = $3;
           upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
           if (arr) {
-            if (size) *size = arr->size;
+            if (size) *size = arr->UPB_PRIVATE(size);
             return ($0*)_upb_array_ptr(arr);
           } else {
             if (size) *size = 0;
@@ -674,12 +674,14 @@ void GenerateRepeatedSetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           UPB_INLINE struct $0* $1_add_$2($1* msg, upb_Arena* arena) {
             upb_MiniTableField field = $4;
             upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-            if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+            if (!arr || !_upb_Array_ResizeUninitialized(
+                            arr, arr->UPB_PRIVATE(size) + 1, arena)) {
               return NULL;
             }
             struct $0* sub = (struct $0*)_upb_Message_New($3, arena);
             if (!arr || !sub) return NULL;
-            UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+            UPB_PRIVATE(_upb_Array_Set)
+            (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
             return sub;
           }
         )cc",
@@ -692,10 +694,12 @@ void GenerateRepeatedSetters(upb::FieldDefPtr field, const DefPoolPair& pools,
           UPB_INLINE bool $1_add_$2($1* msg, $0 val, upb_Arena* arena) {
             upb_MiniTableField field = $3;
             upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-            if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+            if (!arr || !_upb_Array_ResizeUninitialized(
+                            arr, arr->UPB_PRIVATE(size) + 1, arena)) {
               return false;
             }
-            UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+            UPB_PRIVATE(_upb_Array_Set)
+            (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
             return true;
           }
         )cc",
diff --git a/upb_generator/stage0/google/protobuf/compiler/plugin.upb.h b/upb_generator/stage0/google/protobuf/compiler/plugin.upb.h
index 27de0bc0e9..b354a86aab 100644
--- a/upb_generator/stage0/google/protobuf/compiler/plugin.upb.h
+++ b/upb_generator/stage0/google/protobuf/compiler/plugin.upb.h
@@ -196,7 +196,7 @@ UPB_INLINE upb_StringView const* google_protobuf_compiler_CodeGeneratorRequest_f
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -207,7 +207,7 @@ UPB_INLINE const upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_file_
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 1);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -216,7 +216,7 @@ UPB_INLINE upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_file_to_gen
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -258,7 +258,7 @@ UPB_INLINE const struct google_protobuf_FileDescriptorProto* const* google_proto
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 15);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const struct google_protobuf_FileDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -269,7 +269,7 @@ UPB_INLINE const upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_proto
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 15);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -278,7 +278,7 @@ UPB_INLINE upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_proto_file_
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -290,7 +290,7 @@ UPB_INLINE const struct google_protobuf_FileDescriptorProto* const* google_proto
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 17);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const struct google_protobuf_FileDescriptorProto* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -301,7 +301,7 @@ UPB_INLINE const upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_sourc
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 17);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -310,7 +310,7 @@ UPB_INLINE upb_Array* _google_protobuf_compiler_CodeGeneratorRequest_source_file
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -319,7 +319,7 @@ UPB_INLINE upb_StringView* google_protobuf_compiler_CodeGeneratorRequest_mutable
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 1);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (upb_StringView*)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -333,10 +333,12 @@ UPB_INLINE upb_StringView* google_protobuf_compiler_CodeGeneratorRequest_resize_
 UPB_INLINE bool google_protobuf_compiler_CodeGeneratorRequest_add_file_to_generate(google_protobuf_compiler_CodeGeneratorRequest* msg, upb_StringView val, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 1);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return false;
   }
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &val, sizeof(val));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &val, sizeof(val));
   return true;
 }
 UPB_INLINE void google_protobuf_compiler_CodeGeneratorRequest_set_parameter(google_protobuf_compiler_CodeGeneratorRequest *msg, upb_StringView value) {
@@ -359,7 +361,7 @@ UPB_INLINE struct google_protobuf_FileDescriptorProto** google_protobuf_compiler
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 15);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (struct google_protobuf_FileDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -373,19 +375,21 @@ UPB_INLINE struct google_protobuf_FileDescriptorProto** google_protobuf_compiler
 UPB_INLINE struct google_protobuf_FileDescriptorProto* google_protobuf_compiler_CodeGeneratorRequest_add_proto_file(google_protobuf_compiler_CodeGeneratorRequest* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 15);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FileDescriptorProto* sub = (struct google_protobuf_FileDescriptorProto*)_upb_Message_New(google__protobuf__FileDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 UPB_INLINE struct google_protobuf_FileDescriptorProto** google_protobuf_compiler_CodeGeneratorRequest_mutable_source_file_descriptors(google_protobuf_compiler_CodeGeneratorRequest* msg, size_t* size) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 17);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (struct google_protobuf_FileDescriptorProto**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -399,12 +403,14 @@ UPB_INLINE struct google_protobuf_FileDescriptorProto** google_protobuf_compiler
 UPB_INLINE struct google_protobuf_FileDescriptorProto* google_protobuf_compiler_CodeGeneratorRequest_add_source_file_descriptors(google_protobuf_compiler_CodeGeneratorRequest* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorRequest_msg_init(), 17);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_FileDescriptorProto* sub = (struct google_protobuf_FileDescriptorProto*)_upb_Message_New(google__protobuf__FileDescriptorProto_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }
 
@@ -511,7 +517,7 @@ UPB_INLINE const google_protobuf_compiler_CodeGeneratorResponse_File* const* goo
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorResponse_msg_init(), 15);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (const google_protobuf_compiler_CodeGeneratorResponse_File* const*)_upb_array_constptr(arr);
   } else {
     if (size) *size = 0;
@@ -522,7 +528,7 @@ UPB_INLINE const upb_Array* _google_protobuf_compiler_CodeGeneratorResponse_file
   const upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorResponse_msg_init(), 15);
   const upb_Array* arr = upb_Message_GetArray(msg, &field);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -531,7 +537,7 @@ UPB_INLINE upb_Array* _google_protobuf_compiler_CodeGeneratorResponse_file_mutab
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(
       (upb_Message*)msg, &field, arena);
   if (size) {
-    *size = arr ? arr->size : 0;
+    *size = arr ? arr->UPB_PRIVATE(size) : 0;
   }
   return arr;
 }
@@ -556,7 +562,7 @@ UPB_INLINE google_protobuf_compiler_CodeGeneratorResponse_File** google_protobuf
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorResponse_msg_init(), 15);
   upb_Array* arr = upb_Message_GetMutableArray(msg, &field);
   if (arr) {
-    if (size) *size = arr->size;
+    if (size) *size = arr->UPB_PRIVATE(size);
     return (google_protobuf_compiler_CodeGeneratorResponse_File**)_upb_array_ptr(arr);
   } else {
     if (size) *size = 0;
@@ -570,12 +576,14 @@ UPB_INLINE google_protobuf_compiler_CodeGeneratorResponse_File** google_protobuf
 UPB_INLINE struct google_protobuf_compiler_CodeGeneratorResponse_File* google_protobuf_compiler_CodeGeneratorResponse_add_file(google_protobuf_compiler_CodeGeneratorResponse* msg, upb_Arena* arena) {
   upb_MiniTableField field = *upb_MiniTable_FindFieldByNumber(google__protobuf__compiler__CodeGeneratorResponse_msg_init(), 15);
   upb_Array* arr = upb_Message_GetOrCreateMutableArray(msg, &field, arena);
-  if (!arr || !_upb_Array_ResizeUninitialized(arr, arr->size + 1, arena)) {
+  if (!arr || !_upb_Array_ResizeUninitialized(
+                  arr, arr->UPB_PRIVATE(size) + 1, arena)) {
     return NULL;
   }
   struct google_protobuf_compiler_CodeGeneratorResponse_File* sub = (struct google_protobuf_compiler_CodeGeneratorResponse_File*)_upb_Message_New(google__protobuf__compiler__CodeGeneratorResponse__File_msg_init(), arena);
   if (!arr || !sub) return NULL;
-  UPB_PRIVATE(_upb_Array_Set)(arr, arr->size - 1, &sub, sizeof(sub));
+  UPB_PRIVATE(_upb_Array_Set)
+  (arr, arr->UPB_PRIVATE(size) - 1, &sub, sizeof(sub));
   return sub;
 }