apply: diagnose missing argument.

The <trailing-args> argument is required in apply and iapply;
and that is documented.

* eval.c (apply_intrinsic_frob_args): Check for args being
empty and throw.

1 files changed, 3 insertions, 1 deletions

diff --git a/eval.c b/eval.c
index adff9db7..c98625a8 100644
--- a/eval.c
+++ b/eval.c
@@ -1122,7 +1122,9 @@ static val apply_frob_args(val args)
 
 static val apply_intrinsic_frob_args(val args)
 {
-  if (!cdr(args)) {
+  if (!args) {
+    uw_throwf(error_s, lit("apply: trailing-args argument missing"), nao);
+  } if (!cdr(args)) {
     return tolist(car(args));
   } else {
     list_collect_decl (out, ptail);