Transients or scoped immutability

[bearophile]

Don:

> Just use a delegate literal (with a fix to 5081).

This doesn't seem to satisfy two of the things I've written in the original post:
> - On the stack too, avoiding slower heap allocations and avoiding copying them from the mutable to the immutable version;
> - Avoiding calls to functions that may contain loops that DMD doesn't inline;

I don't think a delegate solves the problem.

Bye,
bearophile