Please tell me this is a bug?

[ponce via Digitalmars-d]

On Sunday, 22 February 2015 at 02:27:30 UTC, Peter Alexander 
wrote:
> On Sunday, 22 February 2015 at 01:24:09 UTC, Almighty Bob wrote:
>> a += b; // Compiles with no ERROR!
>>
>> Please tell me that's a bug?
>
> Not a bug. From spec:
>
> http://dlang.org/expression.html#AssignExpression
>> Assignment operator expressions, such as:
>> 
>> a op= b
>> 
>> are semantically equivalent to:
>> 
>> a = cast(typeof(a))(a op b)
>
> Seems questionable to me. Anyone know the rationale? If a = b; 
> is disallowed, I don't see why a += b; should be more 
> acceptable.

Questionable or not, this is the C behaviour we might not depart 
from.