How to use D without the GC ?

[Kagamin]

1) arena allocator makes memory manageable with occasional cache 
invalidation problem
2) no hashtable no problem
3) error handling depends on your code complexity, but even in 
complex C# code I found exceptions as boolean: you either have an 
exception or you don't
4) I occasionally use CTFE, where `@nogc` is a nuisance
5) polymorphism can be a little quirky