Weird codegen bug

[Walter Bright]

On 6/13/2019 4:28 AM, RazvanN wrote:
> import std.stdio : writeln;
> 
> void main()
> {
>      int a = 7;
>      int b = 9;
> 
>      /* some code later */
> 
>      *(&a + 1) = 2;
>      writeln(b);
>      writeln(b);
> }
> 
> This code prints:
> 
> 9
> 2
> 
> with latest version of dmd. Is this a bug or am I missing something? For the 
> record,
> gdc prints (as expected):
> 
> 2
> 2
> 

It's undefined behavior to access memory beyond the boundaries of the memory 
object pointed to:

https://github.com/dlang/dlang.org/pull/2649/files#diff-2bcc1b9af1e2da4f63bfda4b26f114a2R90

in an update to the spec that nobody sees fit to pull :-(