1 files changed, 13 insertions, 7 deletions
diff --git a/objectivec/GPBMessage.m b/objectivec/GPBMessage.m
index 37cff6ce..90485bd1 100644
--- a/objectivec/GPBMessage.m
+++ b/objectivec/GPBMessage.m
@@ -2591,13 +2591,14 @@ static void MergeRepeatedNotPackedFieldFromCodedInputStream(
   if (other == self) {
     return YES;
   }
-  if (![other isKindOfClass:[self class]] &&
-      ![self isKindOfClass:[other class]]) {
+  if (![other isKindOfClass:[GPBMessage class]]) {
     return NO;
   }
-
   GPBMessage *otherMsg = other;
   GPBDescriptor *descriptor = [[self class] descriptor];
+  if ([[otherMsg class] descriptor] != descriptor) {
+    return NO;
+  }
   uint8_t *selfStorage = (uint8_t *)messageStorage_;
   uint8_t *otherStorage = (uint8_t *)otherMsg->messageStorage_;
 
@@ -2997,7 +2998,10 @@ typedef struct ResolveIvarAccessorMethodResult {
   SEL encodingSelector;
 } ResolveIvarAccessorMethodResult;
 
-static void ResolveIvarGet(GPBFieldDescriptor *field,
+// |field| can be __unsafe_unretained because they are created at startup
+// and are essentially global. No need to pay for retain/release when
+// they are captured in blocks.
+static void ResolveIvarGet(__unsafe_unretained GPBFieldDescriptor *field,
                            ResolveIvarAccessorMethodResult *result) {
   GPBDataType fieldDataType = GPBGetFieldDataType(field);
   switch (fieldDataType) {
@@ -3039,7 +3043,8 @@ static void ResolveIvarGet(GPBFieldDescriptor *field,
   }
 }
 
-static void ResolveIvarSet(GPBFieldDescriptor *field,
+// See comment about __unsafe_unretained on ResolveIvarGet.
+static void ResolveIvarSet(__unsafe_unretained GPBFieldDescriptor *field,
                            GPBFileSyntax syntax,
                            ResolveIvarAccessorMethodResult *result) {
   GPBDataType fieldDataType = GPBGetFieldDataType(field);
@@ -3083,9 +3088,10 @@ static void ResolveIvarSet(GPBFieldDescriptor *field,
   // NOTE: hasOrCountSel_/setHasSel_ will be NULL if the field for the given
   // message should not have has support (done in GPBDescriptor.m), so there is
   // no need for checks here to see if has*/setHas* are allowed.
-
   ResolveIvarAccessorMethodResult result = {NULL, NULL};
-  for (GPBFieldDescriptor *field in descriptor->fields_) {
+
+  // See comment about __unsafe_unretained on ResolveIvarGet.
+  for (__unsafe_unretained GPBFieldDescriptor *field in descriptor->fields_) {
     BOOL isMapOrArray = GPBFieldIsMapOrArray(field);
     if (!isMapOrArray) {
       // Single fields.