Thank you!

[Steven Schveighoffer]

On 9/8/21 3:25 AM, Mike Parker wrote:
> On Wednesday, 8 September 2021 at 06:03:49 UTC, Tejas wrote:
> 
>> Please allow this to compile.
>> `int` is value type, so it is fine to generate a temporary and allow 
>> the code to compile, right? A small test will reveal that `integer` is 
>> not being modified, so it's not **that** big of a deal, right?
> 
> There's a big difference between int and struct: the latter is an 
> aggregate that may have member functions that have side effects. For 
> example:
> 
> ```d
> getTemporary().doSomethingWithSideEffects();
> ```
> 
> That's a valid pattern. You might then say that's a different case than 
> the assignment in your example, but `opAssign` for a struct can be 
> overridden.
> 

But in this case, there is no side effect, and the compiler knows it.

TBH, I thought this was already disallowed, but run.dlang.io shows it as 
always succeeding.

One possible explanation is for generic code, but I don't buy that 
actually, because other rvalue/lvalue differences can cause generic code 
to not compile.

I would say disallowing assigning a non-elaborate field (one that is 
just a field, and does not call some arbitrary opAssign) would be a 
valid enhancement.

-Steve