[bluecalm]

Is it really that common? I made this typo a few times in my life. It was corrected every time before the program actually run because the compiler warned me about it. I don't see how you can make this mistake if you're not aggressively trying (by turning off warnings for example).

[ericdevries]

I guess it is not common, but by using the = operator you would not get the warning, and instead get unexpected behaviour.