Warn about unbound functions.

* eval.c (do_expand): If a compound form doesn't expand into
anything, then let us check whether it calls an unbound
function, and issue a warning.

* share/txr/stdlib/place.tl (sys:pl-expand): Move function
definition ahead of first use to suppress unbound function
warning. Eventually we will have a relaxed model of deferred
warning about this.
(sys:placelet-1): Suppress warnings around call to sys:expand
because we are expanding a body into which we inserted
function calls without inserting their definitions.

1 files changed, 4 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index c15ef1c5..8b56cbda 100644
--- a/eval.c
+++ b/eval.c
@@ -3898,8 +3898,11 @@ static val do_expand(val form, val menv)
       val args = rest(form_ex);
       val args_ex = expand_forms(args, menv);
 
-      if (form_ex == form && args_ex == args)
+      if (form_ex == form && args_ex == args) {
+        if (!lookup_fun(menv, sym) && !special_operator_p(sym))
+          eval_warn(last_form_expanded, lit("unbound function ~s"), sym, nao);
         return form;
+      }
 
       if (args_ex == args)
         return form_ex;