Bug 15370 – Some way to manually allocate the closure for delegates to nested functions.

There has been a strong push to move away from the GC, being able to allocate closures with out it would be another step in that direction. As far as I can tell there is no current way to manually allocate a closure. It would be great if there was a solution that could work with allocators to be able to manually allocate closures. Example: auto foo(int x) { int bar(){ return x; } return &bar; // implicitly allocates a closure with the gc // No way to manually allocate it currently } Maybe it could be something as simple as __traits(setClosureAllocator, Mallocator.instance); to set the allocator for the closure of the current function. Allocators then would need to handle the case of freeing the delegate closure as well.

You can manually allocate a closure by using a struct. You allocate the struct, and return it, its `opCall`, or any other member function. As for using allocators - I think we're still far from that. Anything of that magnitude would need to come in the form of a DIP - there's just too much implication to fully capture it here. Since it's possible to manually allocate, closing this as INVALID.