Idea / Pre-RFC: Null-free pointers

I have two. First, RISC-V defines no standard RAM layout which means it's entirely implementation-defined. A conforming RISC-V implementation can place RAM at 0x0, and such implementations exist (e.g. the Micro RISC-V core, 0x0–0x7fb). Whether a particular implementation is a teaching core or a commercial SoC is irrelevant - the point is that the ISA permits it, and Rust should not prohibit what the architecture allows. Second, the BCM2835 (Raspberry Pi 1, ARM1176JZF-S, tens of millions shipped) maps physical RAM starting at 0x0 per the official Broadcom datasheet. Yes, it has an MMU, but an identity map is a legitimate bare-metal design choice, not a workaround. And requiring every OS developer to remap around a language-level assumption is precisely "shifting the language's responsibility onto the user." If Rust intends to be a general-purpose systems language across these targets, "sensibility" must never be assumed.