diff --git a/collects/compiler/zo-parse.rkt b/collects/compiler/zo-parse.rkt
index 6c9493537b..5f47e9cc54 100644
--- a/collects/compiler/zo-parse.rkt
+++ b/collects/compiler/zo-parse.rkt
@@ -111,12 +111,15 @@
                                       (case (check-bit i)
                                         [(0) 'val]
                                         [(1) 'ref]
-                                        [(2) 'flonum])))]
+                                        [(2) 'flonum]
+                                        [else (error "both 'ref and 'flonum argument?")])))]
                      [(closure-types) (for/list ([i (in-range closure-size)]
                                                  [j (in-naturals num-params)])
                                         (case (check-bit j)
                                           [(0) 'val/ref]
-                                          [(2) 'flonum]))])
+                                          [(1) (error "invalid 'ref closure variable")]
+                                          [(2) 'flonum]
+                                          [else (error "both 'ref and 'flonum closure var?")]))])
          (make-lam name
                    (append
                     (if (zero? (bitwise-and flags flags CLOS_PRESERVES_MARKS)) null '(preserves-marks))
diff --git a/src/racket/src/marshal.c b/src/racket/src/marshal.c
index fdab4fd8c9..09d7dd8a63 100644
--- a/src/racket/src/marshal.c
+++ b/src/racket/src/marshal.c
@@ -672,6 +672,16 @@ static Scheme_Object *write_compiled_closure(Scheme_Object *obj)
   svec_size = data->closure_size;
   if (SCHEME_CLOSURE_DATA_FLAGS(data) & CLOS_HAS_TYPED_ARGS) {
     svec_size += ((2 * (data->num_params + data->closure_size)) + BITS_PER_MZSHORT - 1) / BITS_PER_MZSHORT;
+    {
+      int k, mv;
+      for (k = data->num_params + data->closure_size; --k; ) {
+        mv = ((data->closure_map[data->closure_size + ((2 * k) / BITS_PER_MZSHORT)]
+               >> ((2 * k) %  BITS_PER_MZSHORT))
+              & 0x3);
+        if (mv == 0x3)
+          scheme_signal_error("internal error: inconsistent closure/argument type");
+      }
+    }
   }
 
   if (SCHEME_RPAIRP(data->code)) {
diff --git a/src/racket/src/resolve.c b/src/racket/src/resolve.c
index c8ade83fa1..0ea6766036 100644
--- a/src/racket/src/resolve.c
+++ b/src/racket/src/resolve.c
@@ -1927,6 +1927,13 @@ resolve_closure_compilation(Scheme_Object *_data, Resolve_Info *info,
     offset++;
   }
 
+  if (!convert && !just_compute_lift && (offset < data->closure_size) && expanded_already) {
+    /* shift boxmap down, since we're dropping closure elements */
+    int bsz;
+    bsz = boxmap_size(data->num_params + offset);
+    memmove(closure_map + offset, closure_map + data->closure_size, sizeof(mzshort) * bsz);
+  }
+
   /* Reset closure_size, in case a lifted variable was removed: */
   closure_size = offset;
   if (!just_compute_lift) {
@@ -1949,7 +1956,7 @@ resolve_closure_compilation(Scheme_Object *_data, Resolve_Info *info,
       data->num_params = 0;
   } else {
     new_info = resolve_info_extend(info, data->num_params, data->num_params,
-					  cl->base_closure_size + data->num_params);
+                                   cl->base_closure_size + data->num_params);
     for (i = 0; i < data->num_params; i++) {
       resolve_info_add_mapping(new_info, i, i + closure_size + convert_size,
                                (((cl->local_flags[i] & SCHEME_WAS_SET_BANGED)
@@ -1959,7 +1966,7 @@ resolve_closure_compilation(Scheme_Object *_data, Resolve_Info *info,
                                    ? SCHEME_INFO_FLONUM_ARG
                                    : 0)),
                                NULL);
-      if (cl->flonum_map && cl->flonum_map[i])
+      if (cl->flonum_map && cl->flonum_map[i] && !just_compute_lift)
         boxmap_set(closure_map, i + convert_size, 2, closure_size);
     }
     if (expanded_already && !just_compute_lift)