Why does intpromote spew warnings for ~ operator?

[Walter Bright]

On 9/13/2021 1:35 PM, Steven Schveighoffer wrote:
> To reiterate, intpromote is going to require lots of casts, most of which 
> wouldn't change any behavior that is currently happening.

Intpromote has been there for many years, it hasn't caused a big problem.

> The cases where the behavior is different is going from 8 or 16-bit integers to 
> higher bit numbers. IMO, intpromote should focus on those, and leave the others 
> alone.

The thing is, if b is a ubyte:

     ~b

is supposed to be an int, not a ubyte. It's not just about getting the bits right.


> But fixing this problem doesn't mean we have to break all existing code for the 
> purpose of busywork to insert casts to achieve the current behavior.

It needs to move to C behavior.

> I just realized, the deprecation doesn't even say how to replicate current 
> behavior. It says to cast to int before applying the operator, but that's not 
> what current behavior does, it's what the *new* behavior does. Typically, 
> deprecations identify how to adjust your code so it continues to do the same 
> thing. This does the opposite.

The message is about inuring your code so it will work as intended regardless of 
the switch setting.