Good point. I had assumed Rows.Scan() would have just used type switches for efficiency -- it looks like it does for common cases (https://github.com/golang/go/blob/d62866ef793872779c9011161e...) but then falls back to reflect. I wonder why it doesn't just do all of that with type switches? Maybe there are just too many cases and it ends up slower than reflect for the rest of the cases.

Scanner.Scan() is actually just called via a type assertion, though I guess implementations of Scan() might use reflection.