Reordered class fields?

[Peter Summerland]

On Monday, 22 October 2012 at 11:06:50 UTC, Jacob Carlborg wrote:
> On 2012-10-22 10:48, bearophile wrote:
>
>> This page says:
>> http://dlang.org/class.html
>>
>>> The D compiler is free to rearrange the order of fields in a 
>>> class to
>>> optimally pack them in an implementation-defined manner. 
>>> Consider the
>>> fields much like the local variables in a function - the 
>>> compiler
>>> assigns some to registers and shuffles others around all to 
>>> get the
>>> optimal stack frame layout. This frees the code designer to 
>>> organize
>>> the fields in a manner that makes the code more readable 
>>> rather than
>>> being forced to organize it according to machine optimization 
>>> rules.
>>> Explicit control of field layout is provided by struct/union 
>>> types,
>>> not classes.<
>
> Ok, I didn't know that.

The order of the fields is rearranged for packing. Does that 
affect the tupleof property? The example in 
http://dlang.org/class.html for Class properties tulpleof seems 
to implie that the the fields the returned Expression Tuple are 
arranged in lexical order (i.e., as defined by the programmer in 
the class definition). Is this always true for classes? What 
about structs?