262     VerifyOrExit(!rxMessagePtr.IsNull());  in HandleMessage()
404 …return !aHeapString.IsNull() && StringMatch(aHeapString.AsCString(), aName, kStringCaseInsensitive…  in NameMatch()
411     return !aSecond.IsNull() && NameMatch(aFirst, aSecond.AsCString());  in NameMatch()
3016     OT_ASSERT(!mMsgPtr.IsNull());  in Init()
3071         if (mExtraMsgPtr.IsNull())  in SelectMessageFor()
3074             OT_ASSERT(!mExtraMsgPtr.IsNull());  in SelectMessageFor()
3258     if (!mExtraMsgPtr.IsNull())  in IsOverSizeLimit()
3270     mSavedExtraMsgLength = mExtraMsgPtr.IsNull() ? 0 : mExtraMsgPtr->GetLength();  in SaveCurrentState()
3279     if (!mExtraMsgPtr.IsNull())  in RestoreToSavedState()
3334     if (!mExtraMsgPtr.IsNull())  in Send()
3495     VerifyOrExit(!aMessagePtr.IsNull(), error = kErrorInvalidArgs);  in Init()
5211     bool isSubType = !mSubTypeLabel.IsNull();  in Matches()
5237         VerifyOrExit(mSubTypeLabel.IsNull());  in Matches()
5389     if (!mSubTypeLabel.IsNull())  in AppendServiceTypeOrSubTypeTo()