What's the deal with "Warning: explicit element-wise assignment..."

[Steven Schveighoffer via Digitalmars-d]

On Wed, 16 Apr 2014 04:05:57 -0400, Kagamin <spam at here.lot> wrote:

> On Tuesday, 15 April 2014 at 15:59:31 UTC, Steven Schveighoffer wrote:
>> Requiring it simply adds unneeded hoops through which you must jump,  
>> the left hand side denotes the operation, the right hand side does not
>
> Unfortunately, this particular operation is denoted by both sides.

Not really. The = operator (opAssign) is different from the [] = operator  
(opSliceAssign).

I actually am ignorant of how this works under the hood for slices, what  
triggers element-wise copy vs. assign. But for custom types, this is how  
you would have to do it I think.

>> Note -- it would be nice (and more consistent IMO) if arr[] = range  
>> worked identically to arr[] = arr.
>
> Range or array, there are still two ways how it can work. The idea is to  
> give the choice to programmer instead of the compiler.

But programmer cannot define new operators on slices.

>
>> Sorry, I had this wrong. The [] on the left hand side is actually part  
>> of the []= operator.
>
> There's no such operator. You can assign fixed-size array without slice  
> syntax.

Fixed size array is a different type with different semantics from slices.  
You cannot assign the pointer/length of a fixed-size array, so opAssign  
devolves to opSliceAssign.

-Steve