[__david__]

I feel perfectly qualified to say that 2^32 makes no sense.

Just because something is specced doesn't mean that it's reasonable. My "if statement" example is perfectly valid C, but it's not reasonable. 2^32 is perfectly valid, but also unreasonable. Frankly, any bitwise operations with >10 decimal constants are either intentionally obfuscating, or done by someone who doesn't know what they are doing. Consider "2^32" vs "0x02^0x20". The latter is much better.

It is entirely sensible to warn on the premise that it might mean something in another language: The construct seems to be an actual point of confusion (the authors sited numerous real code examples where people are accidentally doing this in the wild), and the construct makes no sense at face value. I think you'd be hard pressed to find a real example of 2^32 in code where it isn't a bug. That's enough to make it a reasonable warning.