diff --git a/libguile/vm-engine.c b/libguile/vm-engine.c
index a79786015..3956a389d 100644
--- a/libguile/vm-engine.c
+++ b/libguile/vm-engine.c
@@ -176,6 +176,10 @@ vm_run (SCM vm, SCM program, SCM args)
     err_args = SCM_EOL;
     goto vm_error;
 
+  vm_error_improper_list:
+    err_msg  = scm_from_locale_string ("VM: Attempt to unroll an improper list: tail is ~A");
+    goto vm_error;
+
   vm_error_no_values:
     err_msg  = scm_from_locale_string ("VM: 0-valued return");
     err_args = SCM_EOL;
diff --git a/libguile/vm-engine.h b/libguile/vm-engine.h
index 22a7ef5e4..215f630b1 100644
--- a/libguile/vm-engine.h
+++ b/libguile/vm-engine.h
@@ -299,6 +299,18 @@ do						\
   PUSH (l);					\
 } while (0)
 
+/* The opposite: push all of the elements in L onto the list. */
+#define PUSH_LIST(l)				\
+do						\
+{						\
+  for (; scm_is_pair (l); l = SCM_CDR (l))      \
+    PUSH (SCM_CAR (l));                         \
+  if (SCM_UNLIKELY (!SCM_NULLP (l))) {          \
+    err_args = scm_list_1 (l);                  \
+    goto vm_error_improper_list;                \
+  }                                             \
+} while (0)
+
 
 /* Below is a (slightly broken) experiment to avoid calling `scm_cell' and to
    allocate cells on the stack.  This is a significant improvement for
diff --git a/libguile/vm-i-system.c b/libguile/vm-i-system.c
index 80eb9249a..fbb94c89a 100644
--- a/libguile/vm-i-system.c
+++ b/libguile/vm-i-system.c
@@ -214,8 +214,7 @@ VM_DEFINE_INSTRUCTION (list_break, "list-break", 0, 0, 0)
 {
   SCM l;
   POP (l);
-  for (; !SCM_NULLP (l); l = SCM_CDR (l))
-    PUSH (SCM_CAR (l));
+  PUSH_LIST (l);
   NEXT;
 }
 
@@ -833,8 +832,7 @@ VM_DEFINE_INSTRUCTION (mv_call, "mv-call", 3, -1, 1)
           POP (values);
           values = scm_struct_ref (values, SCM_INUM0);
           len = scm_length (values);
-          for (; !SCM_NULLP (values); values = SCM_CDR (values))
-            PUSH (SCM_CAR (values));
+          PUSH_LIST (values);
           PUSH (len);
           ip += offset;
         }
@@ -866,8 +864,7 @@ VM_DEFINE_INSTRUCTION (apply, "apply", 1, -1, 1)
   if (len < 0)
     goto vm_error_wrong_type_arg;
 
-  for (; !SCM_NULLP (ls); ls = SCM_CDR (ls))
-    PUSH (SCM_CAR (ls));
+  PUSH_LIST (ls);
 
   nargs += len - 2;
   goto vm_call;
@@ -886,8 +883,7 @@ VM_DEFINE_INSTRUCTION (goto_apply, "goto/apply", 1, -1, 1)
   if (len < 0)
     goto vm_error_wrong_type_arg;
 
-  for (; !SCM_NULLP (ls); ls = SCM_CDR (ls))
-    PUSH (SCM_CAR (ls));
+  PUSH_LIST (ls);
 
   nargs += len - 2;
   goto vm_goto_args;
@@ -949,8 +945,7 @@ VM_DEFINE_INSTRUCTION (goto_cc, "goto/cc", 0, 1, 1)
       SCM values;
       values = scm_struct_ref (cont, SCM_INUM0);
       nvalues = scm_ilength (values);
-      for (; !SCM_NULLP (values); values = SCM_CDR (values))
-        PUSH (SCM_CAR (values));
+      PUSH_LIST (values);
       goto vm_return_values;
     }
   else