Is there anything fundamentally wrong with this code?

[Era Scarecrow via Digitalmars-d-learn]

On Friday, 3 February 2017 at 18:37:15 UTC, Johan Engelen wrote:
> The error is in this line. Instead of assigning to the 
> `postProc` at module scope, you are defining a new local 
> variable and assigning to it.

  Wasn't the compiler suppose to warn you when you are shadowing 
another variable? Or is that only with two local ones?