1 files changed, 4 insertions, 2 deletions

diff --git a/src/alloc.c b/src/alloc.c
index 22a15b4ac59..2c7b02f1158 100644
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -3169,12 +3169,14 @@ allocate_pseudovector (int memlen, int lisplen,
   struct Lisp_Vector *v = allocate_vectorlike (memlen);
 
   /* Catch bogus values.  */
-  eassert (tag <= PVEC_FONT);
+  eassert (0 <= tag && tag <= PVEC_FONT);
+  eassert (0 <= lisplen && lisplen <= zerolen && zerolen <= memlen);
   eassert (memlen - lisplen <= (1 << PSEUDOVECTOR_REST_BITS) - 1);
   eassert (lisplen <= (1 << PSEUDOVECTOR_SIZE_BITS) - 1);
 
-  /* Only the first lisplen slots will be traced normally by the GC.
+  /* Only the first LISPLEN slots will be traced normally by the GC.
      But since Qnil == 0, we can memset Lisp_Object slots as well.  */
+  verify (NIL_IS_ZERO);
   memset (v->contents, 0, zerolen * word_size);
 
   XSETPVECTYPESIZE (v, tag, lisplen, memlen - lisplen);