Scope storage class

[Walter Bright]

Steven Schveighoffer wrote:
> "Walter Bright" wrote
>> Jarrett Billingsley wrote:
>>> So my suspicion is correct, then?  That is:
>>>
>>> scope int delegate() b;
>>> b = { ... };
>>>
>>> Will allocate on the heap?
>> Yes. The scope for delegates takes effect as a parameter storage class, 
>> not a local variable storage class. The reason is because it is the called 
>> function that decides what it's going to do with the delegate.
> 
> Why?  It would be useful to allow local scope delegates.
> 
> The compiler can just forbid passing the delegate to a function which does 
> not declare its parameter as scope.  I assume the compiler knows a variable 
> is scope since it must prevent escape of the delegate, no?  So just use that 
> information.  I thought that was the point of all this...

In order to make that work, the compiler would have to do full escape 
analysis, which is a lot of work to implement.