diff --git a/php/ext/google/protobuf/php-upb.c b/php/ext/google/protobuf/php-upb.c
index 454fd6938d..d592b5d6a2 100644
--- a/php/ext/google/protobuf/php-upb.c
+++ b/php/ext/google/protobuf/php-upb.c
@@ -6097,7 +6097,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
   memcpy(dst, src, mini_table->size);
   for (size_t i = 0; i < mini_table->field_count; ++i) {
     const upb_MiniTableField* field = &mini_table->fields[i];
-    if (!upb_IsRepeatedOrMap(field)) {
+    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
       switch (upb_MiniTableField_CType(field)) {
         case kUpb_CType_Message: {
           upb_TaggedMessagePtr tagged =
@@ -6164,7 +6164,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
     upb_Message_Extension* dst_ext =
         _upb_Message_GetOrCreateExtension(dst, msg_ext->ext, arena);
     if (!dst_ext) return NULL;
-    if (!upb_IsRepeatedOrMap(field)) {
+    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
       if (!upb_Clone_ExtensionValue(msg_ext->ext, msg_ext, dst_ext, arena)) {
         return NULL;
       }
@@ -6835,6 +6835,7 @@ upb_MiniTableEnum* upb_MiniDescriptor_BuildEnum(const char* data, size_t len,
 
 
 #include <inttypes.h>
+#include <stdint.h>
 #include <stdlib.h>
 
 
@@ -7315,7 +7316,7 @@ int upb_MtDecoder_CompareFields(const void* _a, const void* _b) {
 #define UPB_COMBINE(rep, ty, idx) (((rep << type_bits) | ty) << idx_bits) | idx
   uint32_t a_packed = UPB_COMBINE(a->rep, a->type, a->field_index);
   uint32_t b_packed = UPB_COMBINE(b->rep, b->type, b->field_index);
-  assert(a_packed != b_packed);
+  UPB_ASSERT(a_packed != b_packed);
 #undef UPB_COMBINE
   return a_packed < b_packed ? -1 : 1;
 }
@@ -7448,7 +7449,7 @@ static void upb_MtDecoder_ValidateEntryField(upb_MtDecoder* d,
                            name, expected_num, (int)f->number);
   }
 
-  if (upb_IsRepeatedOrMap(f)) {
+  if (upb_MiniTableField_IsRepeatedOrMap(f)) {
     upb_MdDecoder_ErrorJmp(
         &d->base, "map %s cannot be repeated or map, or be in oneof", name);
   }
@@ -7623,7 +7624,7 @@ static const char* upb_MtDecoder_DoBuildMiniTableExtension(
 
   if (extendee->ext & kUpb_ExtMode_IsMessageSet) {
     // Extensions of MessageSet must be messages.
-    if (!upb_IsSubMessage(f)) return NULL;
+    if (!upb_MiniTableField_IsSubMessage(f)) return NULL;
 
     // Extensions of MessageSet must be non-repeating.
     if ((f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Array) return NULL;
@@ -13124,8 +13125,8 @@ static const char* _upb_Decoder_DecodeToMap(upb_Decoder* d, const char* ptr,
 
   UPB_ASSERT(entry);
   UPB_ASSERT(entry->field_count == 2);
-  UPB_ASSERT(!upb_IsRepeatedOrMap(&entry->fields[0]));
-  UPB_ASSERT(!upb_IsRepeatedOrMap(&entry->fields[1]));
+  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[0]));
+  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[1]));
 
   if (!map) {
     map = _upb_Decoder_CreateMap(d, entry);
diff --git a/php/ext/google/protobuf/php-upb.h b/php/ext/google/protobuf/php-upb.h
index f80121d61b..a35625b89c 100644
--- a/php/ext/google/protobuf/php-upb.h
+++ b/php/ext/google/protobuf/php-upb.h
@@ -1086,16 +1086,6 @@ UPB_INLINE void _upb_MiniTableField_CheckIsMap(
   UPB_ASSUME(field->presence == 0);
 }
 
-UPB_INLINE bool upb_IsRepeatedOrMap(const struct upb_MiniTableField* field) {
-  // This works because upb_FieldMode has no value 3.
-  return !(field->mode & kUpb_FieldMode_Scalar);
-}
-
-UPB_INLINE bool upb_IsSubMessage(const struct upb_MiniTableField* field) {
-  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
-         field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
-}
-
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
@@ -1217,20 +1207,32 @@ UPB_API_INLINE upb_CType upb_MiniTableField_CType(const upb_MiniTableField* f) {
   return upb_FieldType_CType(upb_MiniTableField_Type(f));
 }
 
+UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
+    const upb_MiniTableField* field) {
+  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
+}
+
 UPB_API_INLINE bool upb_MiniTableField_IsExtension(
     const upb_MiniTableField* field) {
   return field->mode & kUpb_LabelFlags_IsExtension;
 }
 
-UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
+UPB_API_INLINE bool upb_MiniTableField_IsRepeatedOrMap(
     const upb_MiniTableField* field) {
-  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
+  // This works because upb_FieldMode has no value 3.
+  return !(field->mode & kUpb_FieldMode_Scalar);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsSubMessage(
+    const upb_MiniTableField* field) {
+  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
+         field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
 }
 
 UPB_API_INLINE bool upb_MiniTableField_HasPresence(
     const upb_MiniTableField* field) {
   if (upb_MiniTableField_IsExtension(field)) {
-    return !upb_IsRepeatedOrMap(field);
+    return !upb_MiniTableField_IsRepeatedOrMap(field);
   } else {
     return field->presence != 0;
   }
@@ -2397,7 +2399,7 @@ _upb_MiniTable_ElementSizeLg2(const upb_MiniTableField* field) {
 //                                       const upb_MiniTableField* field,
 //                                       bool value, upb_Arena* a) {
 //     UPB_ASSUME(field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Bool);
-//     UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+//     UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
 //     UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
 //     _upb_Message_SetField(msg, field, &value, a);
 //   }
@@ -2722,7 +2724,7 @@ UPB_API_INLINE bool upb_Message_GetBool(const upb_Message* msg,
                                         bool default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   bool ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2733,7 +2735,7 @@ UPB_API_INLINE bool upb_Message_SetBool(upb_Message* msg,
                                         bool value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2743,7 +2745,7 @@ UPB_API_INLINE int32_t upb_Message_GetInt32(const upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   int32_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2755,7 +2757,7 @@ UPB_API_INLINE bool upb_Message_SetInt32(upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2764,7 +2766,7 @@ UPB_API_INLINE uint32_t upb_Message_GetUInt32(const upb_Message* msg,
                                               uint32_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   uint32_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2775,7 +2777,7 @@ UPB_API_INLINE bool upb_Message_SetUInt32(upb_Message* msg,
                                           uint32_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2784,7 +2786,7 @@ UPB_API_INLINE void upb_Message_SetClosedEnum(
     const upb_MiniTableField* field, int32_t value) {
   UPB_ASSERT(upb_MiniTableField_IsClosedEnum(field));
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   UPB_ASSERT(upb_MiniTableEnum_CheckValue(
       upb_MiniTable_GetSubEnumTable(msg_mini_table, field), value));
   _upb_Message_SetNonExtensionField(msg, field, &value);
@@ -2795,7 +2797,7 @@ UPB_API_INLINE int64_t upb_Message_GetInt64(const upb_Message* msg,
                                             uint64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   int64_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2806,7 +2808,7 @@ UPB_API_INLINE bool upb_Message_SetInt64(upb_Message* msg,
                                          int64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2815,7 +2817,7 @@ UPB_API_INLINE uint64_t upb_Message_GetUInt64(const upb_Message* msg,
                                               uint64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   uint64_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2826,7 +2828,7 @@ UPB_API_INLINE bool upb_Message_SetUInt64(upb_Message* msg,
                                           uint64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2835,7 +2837,7 @@ UPB_API_INLINE float upb_Message_GetFloat(const upb_Message* msg,
                                           float default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   float ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2846,7 +2848,7 @@ UPB_API_INLINE bool upb_Message_SetFloat(upb_Message* msg,
                                          float value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2855,7 +2857,7 @@ UPB_API_INLINE double upb_Message_GetDouble(const upb_Message* msg,
                                             double default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   double ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2866,7 +2868,7 @@ UPB_API_INLINE bool upb_Message_SetDouble(upb_Message* msg,
                                           double value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2876,7 +2878,7 @@ upb_Message_GetString(const upb_Message* msg, const upb_MiniTableField* field,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   upb_StringView ret;
   _upb_Message_GetField(msg, field, &def_val, &ret);
   return ret;
@@ -2888,7 +2890,7 @@ UPB_API_INLINE bool upb_Message_SetString(upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2898,7 +2900,7 @@ UPB_API_INLINE upb_TaggedMessagePtr upb_Message_GetTaggedMessagePtr(
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   upb_TaggedMessagePtr tagged;
   _upb_Message_GetNonExtensionField(msg, field, &default_val, &tagged);
   return tagged;
@@ -2921,7 +2923,7 @@ UPB_API_INLINE void _upb_Message_SetTaggedMessagePtr(
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   UPB_ASSERT(mini_table->subs[field->UPB_PRIVATE(submsg_index)].submsg);
   _upb_Message_SetNonExtensionField(msg, field, &sub_message);
 }
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.c b/ruby/ext/google/protobuf_c/ruby-upb.c
index 70599968c1..b4c0d08d15 100644
--- a/ruby/ext/google/protobuf_c/ruby-upb.c
+++ b/ruby/ext/google/protobuf_c/ruby-upb.c
@@ -5612,7 +5612,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
   memcpy(dst, src, mini_table->size);
   for (size_t i = 0; i < mini_table->field_count; ++i) {
     const upb_MiniTableField* field = &mini_table->fields[i];
-    if (!upb_IsRepeatedOrMap(field)) {
+    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
       switch (upb_MiniTableField_CType(field)) {
         case kUpb_CType_Message: {
           upb_TaggedMessagePtr tagged =
@@ -5679,7 +5679,7 @@ upb_Message* _upb_Message_Copy(upb_Message* dst, const upb_Message* src,
     upb_Message_Extension* dst_ext =
         _upb_Message_GetOrCreateExtension(dst, msg_ext->ext, arena);
     if (!dst_ext) return NULL;
-    if (!upb_IsRepeatedOrMap(field)) {
+    if (!upb_MiniTableField_IsRepeatedOrMap(field)) {
       if (!upb_Clone_ExtensionValue(msg_ext->ext, msg_ext, dst_ext, arena)) {
         return NULL;
       }
@@ -6350,6 +6350,7 @@ upb_MiniTableEnum* upb_MiniDescriptor_BuildEnum(const char* data, size_t len,
 
 
 #include <inttypes.h>
+#include <stdint.h>
 #include <stdlib.h>
 
 
@@ -6830,7 +6831,7 @@ int upb_MtDecoder_CompareFields(const void* _a, const void* _b) {
 #define UPB_COMBINE(rep, ty, idx) (((rep << type_bits) | ty) << idx_bits) | idx
   uint32_t a_packed = UPB_COMBINE(a->rep, a->type, a->field_index);
   uint32_t b_packed = UPB_COMBINE(b->rep, b->type, b->field_index);
-  assert(a_packed != b_packed);
+  UPB_ASSERT(a_packed != b_packed);
 #undef UPB_COMBINE
   return a_packed < b_packed ? -1 : 1;
 }
@@ -6963,7 +6964,7 @@ static void upb_MtDecoder_ValidateEntryField(upb_MtDecoder* d,
                            name, expected_num, (int)f->number);
   }
 
-  if (upb_IsRepeatedOrMap(f)) {
+  if (upb_MiniTableField_IsRepeatedOrMap(f)) {
     upb_MdDecoder_ErrorJmp(
         &d->base, "map %s cannot be repeated or map, or be in oneof", name);
   }
@@ -7138,7 +7139,7 @@ static const char* upb_MtDecoder_DoBuildMiniTableExtension(
 
   if (extendee->ext & kUpb_ExtMode_IsMessageSet) {
     // Extensions of MessageSet must be messages.
-    if (!upb_IsSubMessage(f)) return NULL;
+    if (!upb_MiniTableField_IsSubMessage(f)) return NULL;
 
     // Extensions of MessageSet must be non-repeating.
     if ((f->mode & kUpb_FieldMode_Mask) == kUpb_FieldMode_Array) return NULL;
@@ -12639,8 +12640,8 @@ static const char* _upb_Decoder_DecodeToMap(upb_Decoder* d, const char* ptr,
 
   UPB_ASSERT(entry);
   UPB_ASSERT(entry->field_count == 2);
-  UPB_ASSERT(!upb_IsRepeatedOrMap(&entry->fields[0]));
-  UPB_ASSERT(!upb_IsRepeatedOrMap(&entry->fields[1]));
+  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[0]));
+  UPB_ASSERT(!upb_MiniTableField_IsRepeatedOrMap(&entry->fields[1]));
 
   if (!map) {
     map = _upb_Decoder_CreateMap(d, entry);
diff --git a/ruby/ext/google/protobuf_c/ruby-upb.h b/ruby/ext/google/protobuf_c/ruby-upb.h
index 33e0e3cbff..192c105eb7 100755
--- a/ruby/ext/google/protobuf_c/ruby-upb.h
+++ b/ruby/ext/google/protobuf_c/ruby-upb.h
@@ -1088,16 +1088,6 @@ UPB_INLINE void _upb_MiniTableField_CheckIsMap(
   UPB_ASSUME(field->presence == 0);
 }
 
-UPB_INLINE bool upb_IsRepeatedOrMap(const struct upb_MiniTableField* field) {
-  // This works because upb_FieldMode has no value 3.
-  return !(field->mode & kUpb_FieldMode_Scalar);
-}
-
-UPB_INLINE bool upb_IsSubMessage(const struct upb_MiniTableField* field) {
-  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
-         field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
-}
-
 #ifdef __cplusplus
 } /* extern "C" */
 #endif
@@ -1219,20 +1209,32 @@ UPB_API_INLINE upb_CType upb_MiniTableField_CType(const upb_MiniTableField* f) {
   return upb_FieldType_CType(upb_MiniTableField_Type(f));
 }
 
+UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
+    const upb_MiniTableField* field) {
+  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
+}
+
 UPB_API_INLINE bool upb_MiniTableField_IsExtension(
     const upb_MiniTableField* field) {
   return field->mode & kUpb_LabelFlags_IsExtension;
 }
 
-UPB_API_INLINE bool upb_MiniTableField_IsClosedEnum(
+UPB_API_INLINE bool upb_MiniTableField_IsRepeatedOrMap(
     const upb_MiniTableField* field) {
-  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Enum;
+  // This works because upb_FieldMode has no value 3.
+  return !(field->mode & kUpb_FieldMode_Scalar);
+}
+
+UPB_API_INLINE bool upb_MiniTableField_IsSubMessage(
+    const upb_MiniTableField* field) {
+  return field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Message ||
+         field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Group;
 }
 
 UPB_API_INLINE bool upb_MiniTableField_HasPresence(
     const upb_MiniTableField* field) {
   if (upb_MiniTableField_IsExtension(field)) {
-    return !upb_IsRepeatedOrMap(field);
+    return !upb_MiniTableField_IsRepeatedOrMap(field);
   } else {
     return field->presence != 0;
   }
@@ -2399,7 +2401,7 @@ _upb_MiniTable_ElementSizeLg2(const upb_MiniTableField* field) {
 //                                       const upb_MiniTableField* field,
 //                                       bool value, upb_Arena* a) {
 //     UPB_ASSUME(field->UPB_PRIVATE(descriptortype) == kUpb_FieldType_Bool);
-//     UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+//     UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
 //     UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
 //     _upb_Message_SetField(msg, field, &value, a);
 //   }
@@ -2724,7 +2726,7 @@ UPB_API_INLINE bool upb_Message_GetBool(const upb_Message* msg,
                                         bool default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   bool ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2735,7 +2737,7 @@ UPB_API_INLINE bool upb_Message_SetBool(upb_Message* msg,
                                         bool value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Bool);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_1Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2745,7 +2747,7 @@ UPB_API_INLINE int32_t upb_Message_GetInt32(const upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   int32_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2757,7 +2759,7 @@ UPB_API_INLINE bool upb_Message_SetInt32(upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int32 ||
              upb_MiniTableField_CType(field) == kUpb_CType_Enum);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2766,7 +2768,7 @@ UPB_API_INLINE uint32_t upb_Message_GetUInt32(const upb_Message* msg,
                                               uint32_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   uint32_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2777,7 +2779,7 @@ UPB_API_INLINE bool upb_Message_SetUInt32(upb_Message* msg,
                                           uint32_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt32);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2786,7 +2788,7 @@ UPB_API_INLINE void upb_Message_SetClosedEnum(
     const upb_MiniTableField* field, int32_t value) {
   UPB_ASSERT(upb_MiniTableField_IsClosedEnum(field));
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   UPB_ASSERT(upb_MiniTableEnum_CheckValue(
       upb_MiniTable_GetSubEnumTable(msg_mini_table, field), value));
   _upb_Message_SetNonExtensionField(msg, field, &value);
@@ -2797,7 +2799,7 @@ UPB_API_INLINE int64_t upb_Message_GetInt64(const upb_Message* msg,
                                             uint64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   int64_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2808,7 +2810,7 @@ UPB_API_INLINE bool upb_Message_SetInt64(upb_Message* msg,
                                          int64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Int64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2817,7 +2819,7 @@ UPB_API_INLINE uint64_t upb_Message_GetUInt64(const upb_Message* msg,
                                               uint64_t default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   uint64_t ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2828,7 +2830,7 @@ UPB_API_INLINE bool upb_Message_SetUInt64(upb_Message* msg,
                                           uint64_t value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_UInt64);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2837,7 +2839,7 @@ UPB_API_INLINE float upb_Message_GetFloat(const upb_Message* msg,
                                           float default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   float ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2848,7 +2850,7 @@ UPB_API_INLINE bool upb_Message_SetFloat(upb_Message* msg,
                                          float value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Float);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_4Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2857,7 +2859,7 @@ UPB_API_INLINE double upb_Message_GetDouble(const upb_Message* msg,
                                             double default_val) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   double ret;
   _upb_Message_GetField(msg, field, &default_val, &ret);
   return ret;
@@ -2868,7 +2870,7 @@ UPB_API_INLINE bool upb_Message_SetDouble(upb_Message* msg,
                                           double value, upb_Arena* a) {
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Double);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_8Byte);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2878,7 +2880,7 @@ upb_Message_GetString(const upb_Message* msg, const upb_MiniTableField* field,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   upb_StringView ret;
   _upb_Message_GetField(msg, field, &def_val, &ret);
   return ret;
@@ -2890,7 +2892,7 @@ UPB_API_INLINE bool upb_Message_SetString(upb_Message* msg,
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_String ||
              upb_MiniTableField_CType(field) == kUpb_CType_Bytes);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) == kUpb_FieldRep_StringView);
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   return _upb_Message_SetField(msg, field, &value, a);
 }
 
@@ -2900,7 +2902,7 @@ UPB_API_INLINE upb_TaggedMessagePtr upb_Message_GetTaggedMessagePtr(
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   upb_TaggedMessagePtr tagged;
   _upb_Message_GetNonExtensionField(msg, field, &default_val, &tagged);
   return tagged;
@@ -2923,7 +2925,7 @@ UPB_API_INLINE void _upb_Message_SetTaggedMessagePtr(
   UPB_ASSUME(upb_MiniTableField_CType(field) == kUpb_CType_Message);
   UPB_ASSUME(_upb_MiniTableField_GetRep(field) ==
              UPB_SIZE(kUpb_FieldRep_4Byte, kUpb_FieldRep_8Byte));
-  UPB_ASSUME(!upb_IsRepeatedOrMap(field));
+  UPB_ASSUME(!upb_MiniTableField_IsRepeatedOrMap(field));
   UPB_ASSERT(mini_table->subs[field->UPB_PRIVATE(submsg_index)].submsg);
   _upb_Message_SetNonExtensionField(msg, field, &sub_message);
 }