Why does intpromote spew warnings for ~ operator?

[Guillaume Piolat]

On Sunday, 12 September 2021 at 14:14:03 UTC, Steven 
Schveighoffer wrote:
> With the -preview=intpromote switch, the uncasted negation 
> compiles and runs as expected.
> 
> Right now, the deprecation is telling users under penalty of 
> not compiling to do something that will achieve nothing when 
> intpromote is enabled.

What is achieve is that people can review the place where -x and 
~x were used, and see if there was bug there ; because it is a 
real possibility that C code was ported and then it has a 
different semantics.

The end game of it is:

    A. "when you paste C code and it builds then it's the same"

instead of:

    B. "when you paste C code and it builds then it's the same, 
EXCEPT -x and ~x who don't promote their operand to int"


when people of the future come to D in 2030 they will enjoy the 
proposition A instead of B.