New abstraction: Layout

[rikki cattermole]

On 17/02/2018 12:04 AM, Andrei Alexandrescu wrote:
> I've been long bothered that the builtin .tupleof and our own 
> abstractions Fields and RepresentationTypeTuple in std.traits - all omit 
> the essential information of field offsets. That makes types that use 
> align() to have the same .tupleof, Fields, and RepresentationTypeTuple 
> even though they shouldn't.
> 
> The right answer is Layout a tuple of (offset, type) pairs describing 
> entirely the memory layout of a type. We need such for memory 
> allocation, garbage collection, serialization, and more.
> 
> The implementation turned out to be quite compact - 81 lines including a 
> compile-time mergesort. Destroy!
> 
> https://github.com/dlang/phobos/pull/6192
> 
> 
> Andrei

Could use the name for the field as well. At the minimum useful for 
debugging purposes.