DIP: add Bit Fields

[ryuukk_]

On Thursday, 7 March 2024 at 04:26:56 UTC, Walter Bright wrote:
> https://github.com/WalterBright/documents/blob/master/bitfields.md

Have you ever thought of the idea of using bit specific integers?

I once saw this one suggestion on the IRC channel: `alias i1 = 
__traits(integer, signed: false, 1);`



```D
alias u1 = __traits(integer, true, 1);
alias u3 = __traits(integer, true, 3);
alias u5 = __traits(integer, true, 5);
align(1) struct S
{
     u1 isnothrow;        // nothrow
     u1 isnogc;           // is @nogc
     u1 isproperty;       // can be called without parentheses
     u1 isref;            // returns a reference
     u1 isreturn;         // 'this' is returned by ref
     u1 isscope;          // 'this' is scope
     u1 isreturninferred; // 'this' is return from inference
     u1 isscopeinferred;  // 'this' is scope from inference
     u1 islive;           // is @live
     u1 incomplete;       // return type or default arguments 
removed
     u1 inoutParam;       // inout on the parameters
     u1 inoutQual;        // inout on the qualifier
     u5 a;
     u3 flags;
}
```