diff --git a/src/eval.c b/src/eval.c
index c30c5d8..484f9bc 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -247,6 +247,7 @@
 static void delete_var(hashtab_T *ht, hashitem_T *hi);
 static void list_one_var(dictitem_T *v, char *prefix, int *first);
 static void list_one_var_a(char *prefix, char_u *name, int type, char_u *string, int *first);
+static int tv_check_lock(typval_T *tv, char_u *name, int use_gettext);
 static char_u *find_option_end(char_u **arg, int *opt_flags);
 
 /* for VIM_VERSION_ defines */
@@ -2332,9 +2333,8 @@
 					     &tv, &di, TRUE, FALSE) == OK)
 	    {
 		if ((di == NULL
-		       || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
-			  && !tv_check_lock(di->di_tv.v_lock, lp->ll_name,
-								  FALSE)))
+			 || (!var_check_ro(di->di_flags, lp->ll_name, FALSE)
+			   && !tv_check_lock(&di->di_tv, lp->ll_name, FALSE)))
 			&& tv_op(&tv, rettv, op) == OK)
 		    set_var(lp->ll_name, &tv, FALSE);
 		clear_tv(&tv);
@@ -2344,7 +2344,7 @@
 	    set_var(lp->ll_name, rettv, copy);
 	*endp = cc;
     }
-    else if (tv_check_lock(lp->ll_newkey == NULL
+    else if (var_check_lock(lp->ll_newkey == NULL
 		? lp->ll_tv->v_lock
 		: lp->ll_tv->vval.v_dict->dv_lock, lp->ll_name, FALSE))
 	;
@@ -2358,7 +2358,7 @@
 	 */
 	for (ri = rettv->vval.v_list->lv_first; ri != NULL && ll_li != NULL; )
 	{
-	    if (tv_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
+	    if (var_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
 		return;
 	    ri = ri->li_next;
 	    if (ri == NULL || (!lp->ll_empty2 && lp->ll_n2 == ll_n1))
@@ -2951,9 +2951,9 @@
 	*name_end = cc;
     }
     else if ((lp->ll_list != NULL
-		   && tv_check_lock(lp->ll_list->lv_lock, lp->ll_name, FALSE))
+		 && var_check_lock(lp->ll_list->lv_lock, lp->ll_name, FALSE))
 	    || (lp->ll_dict != NULL
-		  && tv_check_lock(lp->ll_dict->dv_lock, lp->ll_name, FALSE)))
+		 && var_check_lock(lp->ll_dict->dv_lock, lp->ll_name, FALSE)))
 	return FAIL;
     else if (lp->ll_range)
     {
@@ -2964,7 +2964,7 @@
 	while (ll_li != NULL && (lp->ll_empty2 || lp->ll_n2 >= ll_n1))
 	{
 	    li = ll_li->li_next;
-	    if (tv_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
+	    if (var_check_lock(ll_li->li_tv.v_lock, lp->ll_name, FALSE))
 		return FAIL;
 	    ll_li = li;
 	    ++ll_n1;
@@ -3034,7 +3034,7 @@
 	    di = HI2DI(hi);
 	    if (var_check_fixed(di->di_flags, name, FALSE)
 		    || var_check_ro(di->di_flags, name, FALSE)
-		    || tv_check_lock(d->dv_lock, name, FALSE))
+		    || var_check_lock(d->dv_lock, name, FALSE))
 		return FAIL;
 
 	    delete_var(ht, hi);
@@ -7866,7 +7866,7 @@
     {
 	/* existing variable, need to clear the value */
 	if (var_check_ro(v->di_flags, name, FALSE)
-			       || tv_check_lock(v->di_tv.v_lock, name, FALSE))
+			      || var_check_lock(v->di_tv.v_lock, name, FALSE))
 	    return;
 
 	/*
@@ -8021,31 +8021,12 @@
 }
 
 /*
- * Check if a variable name is valid.
- * Return FALSE and give an error if not.
- */
-    int
-valid_varname(char_u *varname)
-{
-    char_u *p;
-
-    for (p = varname; *p != NUL; ++p)
-	if (!eval_isnamec1(*p) && (p == varname || !VIM_ISDIGIT(*p))
-						   && *p != AUTOLOAD_CHAR)
-	{
-	    semsg(_(e_illvar), varname);
-	    return FALSE;
-	}
-    return TRUE;
-}
-
-/*
- * Return TRUE if typeval "tv" is set to be locked (immutable).
+ * Return TRUE if "flags" indicates variable "name" is locked (immutable).
  * Also give an error message, using "name" or _("name") when use_gettext is
  * TRUE.
  */
     int
-tv_check_lock(int lock, char_u *name, int use_gettext)
+var_check_lock(int lock, char_u *name, int use_gettext)
 {
     if (lock & VAR_LOCKED)
     {
@@ -8067,6 +8048,56 @@
 }
 
 /*
+ * Return TRUE if typeval "tv" and its value are set to be locked (immutable).
+ * Also give an error message, using "name" or _("name") when use_gettext is
+ * TRUE.
+ */
+    static int
+tv_check_lock(typval_T *tv, char_u *name, int use_gettext)
+{
+    int	lock = 0;
+
+    switch (tv->v_type)
+    {
+	case VAR_BLOB:
+	    if (tv->vval.v_blob != NULL)
+		lock = tv->vval.v_blob->bv_lock;
+	    break;
+	case VAR_LIST:
+	    if (tv->vval.v_list != NULL)
+		lock = tv->vval.v_list->lv_lock;
+	    break;
+	case VAR_DICT:
+	    if (tv->vval.v_dict != NULL)
+		lock = tv->vval.v_dict->dv_lock;
+	    break;
+	default:
+	    break;
+    }
+    return var_check_lock(tv->v_lock, name, use_gettext)
+		    || (lock != 0 && var_check_lock(lock, name, use_gettext));
+}
+
+/*
+ * Check if a variable name is valid.
+ * Return FALSE and give an error if not.
+ */
+    int
+valid_varname(char_u *varname)
+{
+    char_u *p;
+
+    for (p = varname; *p != NUL; ++p)
+	if (!eval_isnamec1(*p) && (p == varname || !VIM_ISDIGIT(*p))
+						   && *p != AUTOLOAD_CHAR)
+	{
+	    semsg(_(e_illvar), varname);
+	    return FALSE;
+	}
+    return TRUE;
+}
+
+/*
  * Copy the values from typval_T "from" to typval_T "to".
  * When needed allocates string or increases reference count.
  * Does not make a copy of a list, blob or dict but copies the reference!
@@ -10711,13 +10742,13 @@
     else if (argvars[0].v_type == VAR_LIST)
     {
 	if ((l = argvars[0].vval.v_list) == NULL
-	      || (!map && tv_check_lock(l->lv_lock, arg_errmsg, TRUE)))
+	      || (!map && var_check_lock(l->lv_lock, arg_errmsg, TRUE)))
 	    return;
     }
     else if (argvars[0].v_type == VAR_DICT)
     {
 	if ((d = argvars[0].vval.v_dict) == NULL
-	      || (!map && tv_check_lock(d->dv_lock, arg_errmsg, TRUE)))
+	      || (!map && var_check_lock(d->dv_lock, arg_errmsg, TRUE)))
 	    return;
     }
     else
@@ -10755,9 +10786,10 @@
 
 		    --todo;
 		    di = HI2DI(hi);
-		    if (map &&
-			    (tv_check_lock(di->di_tv.v_lock, arg_errmsg, TRUE)
-			    || var_check_ro(di->di_flags, arg_errmsg, TRUE)))
+		    if (map && (var_check_lock(di->di_tv.v_lock,
+							   arg_errmsg, TRUE)
+				|| var_check_ro(di->di_flags,
+							   arg_errmsg, TRUE)))
 			break;
 		    vimvars[VV_KEY].vv_str = vim_strsave(di->di_key);
 		    r = filter_map_one(&di->di_tv, expr, map, &rem);
@@ -10813,7 +10845,7 @@
 
 	    for (li = l->lv_first; li != NULL; li = nli)
 	    {
-		if (map && tv_check_lock(li->li_tv.v_lock, arg_errmsg, TRUE))
+		if (map && var_check_lock(li->li_tv.v_lock, arg_errmsg, TRUE))
 		    break;
 		nli = li->li_next;
 		vimvars[VV_KEY].vv_nr = idx;