It’s a floating-point value, but it is not a number. And, okay, yes, 2**53 is another number which is equal to itself plus one. But that is still not a solution to an equation. How is it useful as a feature?
That’s a gross misrepresentation. Floating point values CAN be compared for equality, but it doesn’t always behave in a way that is intuitive when you start from an assumption of decimal floats, and the issues generally show up when working with fifths - that is to say, fractions. Not integers. Testing a+1 == a is most absolutely NOT undocumented behaviour.
I don’t understand what is going on in this thread, other than a lot of float FUD.