It's kind of a funny space; right now Rust handily gives you "no allocations" (this is where I live) or "infallible + fallible allocations" (this is alloc/std by default) but not "only fallible allocations". This sort of thing is basically filling out the quadrant of options.
Yup, it is. If this plan linked above were to be implemented, what would happen is that you would get the same behaviors by default, but with a new setting, you'd get some APIs removed. That's backwards compatible.
It's kind of a funny space; right now Rust handily gives you "no allocations" (this is where I live) or "infallible + fallible allocations" (this is alloc/std by default) but not "only fallible allocations". This sort of thing is basically filling out the quadrant of options.