So these two compile and, in non-debug builds, run just fine

[Era Scarecrow via Digitalmars-d]

On Friday, 25 November 2016 at 15:30:35 UTC, Steven Schveighoffer 
wrote:
> But I think Walter's scope changes (DIP 1001 I think?) will 
> make it so the compiler rejects this even in non-safe mode.

  Rejecting it would be nice...

  Although I wonder... I've been wondering and thinking about if 
we could add extra metadata to non-release code for the purpose 
of debugging. The idea being every variable will have an attached 
hidden metadata tag/field (let's assume 32bits). This can then 
flag the information in various ways. For memory allocation we 
have stack/GC/static/other, then we have if this was passed back 
from a function, was modified. Basic type information could 
specify what the general type origin was (when first 
allocated/first assigned), was a slice of large data, originally 
was const, or immutable, shared, a pointer that's been tampered 
with (say using bits for extra data vs an actual pointer), and 
anything else we wanted to potentially track.

  While this information isn't useful on the surface, hidden 
checks could be thrown out there, like returning a variable from 
the local stack when it might otherwise be obfuscated and hidden.