Ha, looking through the links dang added, I came upon something I wrote back in December

I gave (somewhat arbitrarily) the example that safe Rust is OK with a 64-bit pointer (on a modern PC for example) having the value made by the UTF-8 text "LAUGHING". That's 8 bytes, 8 bytes is 64 bits, it fits perfectly. Of course I point out, unsafe Rust, which is allowed to dereference pointers, must never dereference this LAUGHING pointer, it's not actually pointing at anything, but it is allowed to exist in safe Rust.

Coincidentally, in like February or so this year, a new third-party Rust type "ColdString" was introduced to their reddit by somebody I've never met - I read about it and encouraged its author. ColdString is 64 bits (on modern hardware) because inside it's a pointer, and indeed if the text you wanted to store in a ColdString was "LAUGHING" you do that exactly as I described in the December post - it's just the UTF-8 encoded text, no problem. The clever trick inside ColdString is how it can know when that 64-bit pointer really is actually a pointer for longer strings - yet also allows any 0 to 8 byte UTF-8 text string to just be encoded in the ColdString itself directly.