places: use Lisp-1 macroexpansion where needed.

A test case for this very subtle bug is this:

  (let ((v (list 1 2 3)))
    (symacrolet ((x v))
      (flet ((x () 42))
        (set [x 0] 0))))

Because x is being evaluated in the DWIM brackets which
flatten the two namespaces into one, it must be treated as a
reference to the flet, and so [x 0] denotes the function call.
The assignment is erroneous.

The incorrect behavior being fixed is that the places code
macro-expands x in the Lisp-2 style under which the symacrolet
is not shadowed by the flet. The substitution of v takes
place, and the assignment assigns to [v 0].

* share/txr/stdlib/place.tl (sys:l1-setq, sys:l1-val):
Use macroexpand-lisp1 rather than macroexpand.

1 files changed, 2 insertions, 2 deletions

diff --git a/share/txr/stdlib/place.tl b/share/txr/stdlib/place.tl
index 2ae0d839..9621269b 100644
--- a/share/txr/stdlib/place.tl
+++ b/share/txr/stdlib/place.tl
@@ -35,7 +35,7 @@
     (throwf 'eval-error . params))
 
   (defmacro sys:l1-setq (u-expr new-val :env e)
-    (let ((e-expr (macroexpand u-expr e)))
+    (let ((e-expr (macroexpand-lisp1 u-expr e)))
       (if (symbolp e-expr)
         (caseq (lexical-lisp1-binding e e-expr)
           (:var ^(sys:setq ,e-expr ,new-val))
@@ -46,7 +46,7 @@
         ^(set ,u-expr ,new-val))))
 
   (defmacro sys:l1-val (u-expr :env e)
-    (let ((e-expr (macroexpand u-expr e)))
+    (let ((e-expr (macroexpand-lisp1 u-expr e)))
       (if (and (symbolp e-expr) (not (constantp e-expr)))
         (caseq (lexical-lisp1-binding e e-expr)
           (:fun ^(fun ,e-expr))