On Friday, 19 February 2016 at 22:34:48 UTC, Chris Wright wrote:
>
> I tested this a fair bit today, and I haven't been able to do any of the nefarious things I expected to be able to do. No overwriting variables in the caller's scope, no smashing stack pointers, etc.
>
> I was surprised by this result, but in retrospect, it's relatively obvious. The caller pushes variables onto the stack and sets the stack pointer for the callee. It wouldn't send a stack pointer that pointed into its own stack frame.

Thanks for taking the time to test.

The more I've thought about it, the more I wonder if there should be a restriction so that casts of function pointers/delegate maintain the same number of parameters. Even though you haven't been able to do nefarious things, it's giving a completely wrong answer than you would expect. The result of the answer might cause bad things to happen in a program. Further, to even understand what's going wrong you have to understand how the compiler is generating assembly. I've been using D for like a year or so, and I would never have been able to figure out the reason by myself.

Or at least in safe code you shouldn't be able to do this.