Comment by tialaramex

Generously I assume Bill is thinking of "register classes" as types, so it doesn't care that you're using LEA on an integer, just that you used one of the registers for which LEA is available and not say XMM0

Ultimately the proof is in the pudding. If I screw up some inline assembly in Rust the diagnostics aren't very good because Rust doesn't deeply understand the assembly, whereas obviously for other things they're excellent. If Odin's diagnostics are great because it actually understands these "templates" that's a meaningful benefit to programmers.