Re: pathological byte-compilation

[Richard Stallman]

    That transformation assumed a `lexical style' use of `let', which isn't
    something you can do generally, but in the case of defsubst, I think it
    would probably be safe to say that argument bindings are not guaranteed
    to be visible (via dynamic binding) in functions called from defsubt
    body.

I hesitate to agree with this.  However, in many defsubsts only
primitives will be called.  It should be possible to determine that
nothing called from the defsubst will ever look at variable bindings.