diff --git a/src/typval.c b/src/typval.c
index 29c925d..b73c500 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -575,63 +575,7 @@
 }
 
 /*
- * Give an error and return FAIL unless "args[idx]" is a string or
- * a number (buffer)
- */
-    int
-check_for_buffer_arg(typval_T *args, int idx)
-{
-    if (args[idx].v_type != VAR_STRING && args[idx].v_type != VAR_NUMBER)
-    {
-	if (idx >= 0)
-	    semsg(_(e_string_required_for_argument_nr), idx + 1);
-	else
-	    emsg(_(e_stringreq));
-	return FAIL;
-    }
-    return OK;
-}
-
-/*
- * Give an error and return FAIL unless "args[idx]" is a string or
- * a number (line)
- */
-    int
-check_for_lnum_arg(typval_T *args, int idx)
-{
-    if (args[idx].v_type != VAR_STRING && args[idx].v_type != VAR_NUMBER)
-    {
-	if (idx >= 0)
-	    semsg(_(e_string_required_for_argument_nr), idx + 1);
-	else
-	    emsg(_(e_stringreq));
-	return FAIL;
-    }
-    return OK;
-}
-
-/*
- * Give an error and return FAIL unless "args[idx]" is a string or
- * a number (line)
- */
-    int
-check_for_opt_lnum_arg(typval_T *args, int idx)
-{
-    if (args[idx].v_type != VAR_UNKNOWN
-	    && args[idx].v_type != VAR_STRING
-	    && args[idx].v_type != VAR_NUMBER)
-    {
-	if (idx >= 0)
-	    semsg(_(e_string_required_for_argument_nr), idx + 1);
-	else
-	    emsg(_(e_stringreq));
-	return FAIL;
-    }
-    return OK;
-}
-
-/*
- * Check for an optional string or number argument at 'idx'
+ * Check for an optional string or number argument at 'idx'.
  */
     int
 check_for_opt_string_or_number_arg(typval_T *args, int idx)
@@ -641,6 +585,46 @@
 }
 
 /*
+ * Give an error and return FAIL unless "args[idx]" is a buffer number.
+ * Buffer number can be a number or a string.
+ */
+    int
+check_for_buffer_arg(typval_T *args, int idx)
+{
+    return check_for_string_or_number_arg(args, idx);
+}
+
+/*
+ * Check for an optional buffer argument at 'idx'
+ */
+    int
+check_for_opt_buffer_arg(typval_T *args, int idx)
+{
+    return (args[idx].v_type == VAR_UNKNOWN
+	    || check_for_buffer_arg(args, idx));
+}
+
+/*
+ * Give an error and return FAIL unless "args[idx]" is a line number.
+ * Line number can be a number or a string.
+ */
+    int
+check_for_lnum_arg(typval_T *args, int idx)
+{
+    return check_for_string_or_number_arg(args, idx);
+}
+
+/*
+ * Check for an optional line number argument at 'idx'
+ */
+    int
+check_for_opt_lnum_arg(typval_T *args, int idx)
+{
+    return (args[idx].v_type == VAR_UNKNOWN
+	    || check_for_lnum_arg(args, idx));
+}
+
+/*
  * Give an error and return FAIL unless "args[idx]" is a string or
  * a blob.
  */
@@ -659,6 +643,44 @@
 }
 
 /*
+ * Give an error and return FAIL unless "args[idx]" is a string or
+ * a list.
+ */
+    int
+check_for_string_or_list_arg(typval_T *args, int idx)
+{
+    if (args[idx].v_type != VAR_STRING && args[idx].v_type != VAR_LIST)
+    {
+	if (idx >= 0)
+	    semsg(_(e_string_required_for_argument_nr), idx + 1);
+	else
+	    emsg(_(e_stringreq));
+	return FAIL;
+    }
+    return OK;
+}
+
+/*
+ * Give an error and return FAIL unless "args[idx]" is a buffer
+ * number or a dict.
+ */
+    int
+check_for_buffer_or_dict_arg(typval_T *args, int idx)
+{
+    if (args[idx].v_type != VAR_STRING
+	    && args[idx].v_type != VAR_NUMBER
+	    && args[idx].v_type != VAR_DICT)
+    {
+	if (idx >= 0)
+	    semsg(_(e_string_required_for_argument_nr), idx + 1);
+	else
+	    emsg(_(e_stringreq));
+	return FAIL;
+    }
+    return OK;
+}
+
+/*
  * Get the string value of a variable.
  * If it is a Number variable, the number is converted into a string.
  * tv_get_string() uses a single, static buffer.  YOU CAN ONLY USE IT ONCE!