with (auto p = new ...)

[Meta via Digitalmars-d-learn]

I think this is just a language oversight. It's allowed in if 
statements, and people have made a good case for allowing it for 
switch statements. It just hasn't been implemented. I made an 
attempt one evening to implement it for switch statements,  but 
I'm not at all familiar with DMD, so I put it on the back burner 
for the time being.