Nithin Thomas Exactly, since you're not using a mutex, you'll run into race conditions if you modify newData somewhere else in your code while one of your goroutines is also modifying it.

I know this is a simple example but channels don't guarantee exclusive access, if you modify newData (it being a pointer) anywhere else in your code you'll probably run into a race condition. (Also there a few typos in your code, like the name of the channel in main and d.list which should be d.numbers).