bugfix: code-walk the result of a declined macro.

When a form is a macro, but the macro declines to expand the
form, the form must still be code walked; we can't just return
it and be done.  For instance if it is a function call, its
argument expressions have to be expanded.

This also causes undefined function warning to be generated
properly if a macro declines, and the resulting form is
a function call to a not-yet-defined function.

* eval.c (do_expand): If expand_macro yields the original
form, branch backwards to re-execute the whole if statement
again. Use the fact that the local variable macro is now
non-nil to skip the macro expansion case.

1 files changed, 3 insertions, 2 deletions

diff --git a/eval.c b/eval.c
index ab7518f6..5dc34960 100644
--- a/eval.c
+++ b/eval.c
@@ -4063,6 +4063,7 @@ static val do_expand(val form, val menv)
 
   menv = default_null_arg(menv);
 
+again:
   if (nilp(form)) {
     return nil;
   } else if (bindable(form)) {
@@ -4341,10 +4342,10 @@ static val do_expand(val form, val menv)
       return rlcp(cons(sym, args_ex), form);
     } else if (sym == switch_s) {
       return expand_switch(form, menv);
-    } else if ((macro = lookup_mac(menv, sym))) {
+    } else if (!macro && (macro = lookup_mac(menv, sym))) {
       val mac_expand = expand_macro(form, macro, menv);
       if (mac_expand == form)
-        return form;
+        goto again;
       return expand(rlcp_tree(rlcp_tree(mac_expand, form), macro), menv);
     } else if (sym == progn_s) {
       val args = rest(form);