[Joke] C++ and D namings

[Steven Schveighoffer]

On 1/20/21 10:31 AM, Paul Backus wrote:
> On Wednesday, 20 January 2021 at 15:17:09 UTC, Steven Schveighoffer wrote:
>> On 1/20/21 10:13 AM, Paul Backus wrote:
>>>
>>> This version compiles even with @safe:
>>>
>>> import std.stdio;
>>> union t {int x; immutable int y;};
>>> void main() @safe
>>> {
>>>
>>>      t a = { x: 0 };
>>>      writeln(a.y);
>>>      t b = { y: 4 };
>>>      a = b; // oops
>>>      writeln(a.y);
>>> }
>>
>> That seems like a bug. Writing the x directly fails in @safe code.
>>
> 
> I agree. Though now that I take a look at the spec, it seems like the 
> bug may actually be in the line
> 
>      writeln(a.y);
> 
> ...since accessing immutable data that's overlapped with mutable data 
> breaks safe aliasing [1].
> 

Thanks for that link, I wasn't aware of that list.

In my Dconf online presentation, I found numerous bugs surrounding 
unions and @safe code.

For instance, a union between a pointer and a scalar is considered 
"safe" to access the scalar (even writing it!)

-Steve