bug#411: 23.0.60; flet and byte-compilation

[Glenn Morris]

Michael Heerdegen wrote:

> (defun f (x y)
>   (flet ((+ (a b) (- a b)))
>     (+ x y)))
> 
> Bytecompile it [...]
> 
> Evaluate the expression (f 1 2). This should yield -1, but the result
> will be 3.

Some (much delayed) observations:

1) it works to use `labels' instead of `flet'

2) it works to comment out the line in bytecomp.el

(byte-defop-compiler (+ byte-plus)  byte-compile-associative)

I guess byte-compile-associative mangles the '(+ x y) form without
regard for the redefinition in effect. I don't know if that is
fixable, or should be a documented caveat with regards to primitives.