go - Custom errors in golang and pointer receivers

Question

Reading about value receivers vs pointer receivers across the web and stackoverflow, I understand the basic rule to be: If you don't plan to modify the receiver, and the receiver is relatively small, there is no need for pointers.

Then, reading about implementing the error interface (eg. https://blog.golang.org/error-handling-and-go), I see that examples of the Error() function all use pointer receiver.

Yet, we are not modifying the receiver, and the struct is very small.

I feel like the code is much nicer without pointers (return &appError{} vs return appError{}).

Is there a reason why the examples are using pointers?

Answer 1

Waitting for answers