Go 1.8

The header comment of Process implies that the use of the src parameter is optional. However providing a nil value always results in the error:

expected 'package', found 'EOF'

This is because the value is a nil []byte but the go parser ParseFile function which is called internally expects src to be of type interface{}. This in turns causes readSource to return nil because the comparison with (interface{}) nil fails.

Either the header comment of Process should be updated or the code modified so that giving a nil src actually works (presumably the intended and better behavior). This requires tweaking the call to ParseFile to cast src to a nil interface{} if it's a nil []byte.