diff --git a/diff.c b/diff.c
index 99871d2546..47146c33f5 100644
--- a/diff.c
+++ b/diff.c
@@ -4736,10 +4736,13 @@ static unsigned filter_bit_tst(char status, const struct diff_options *opt)
 	return opt->filter & filter_bit[(int) status];
 }
 
-static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
+static int diff_opt_diff_filter(const struct option *option,
+				const char *optarg, int unset)
 {
+	struct diff_options *opt = option->value;
 	int i, optch;
 
+	BUG_ON_OPT_NEG(unset);
 	prepare_filter_bits();
 
 	/*
@@ -4770,7 +4773,8 @@ static int parse_diff_filter_opt(const char *optarg, struct diff_options *opt)
 
 		bit = (0 <= optch && optch <= 'Z') ? filter_bit[optch] : 0;
 		if (!bit)
-			return optarg[i];
+			return error(_("unknown change class '%c' in --diff-filter=%s"),
+				     optarg[i], optarg);
 		if (negate)
 			opt->filter &= ~bit;
 		else
@@ -5389,6 +5393,9 @@ static void prep_parse_options(struct diff_options *options)
 		OPT_CALLBACK_F(0, "find-object", options, N_("<object-id>"),
 			       N_("look for differences that change the number of occurrences of the specified object"),
 			       PARSE_OPT_NONEG, diff_opt_find_object),
+		OPT_CALLBACK_F(0, "diff-filter", options, N_("[(A|C|D|M|R|T|U|X|B)...[*]]"),
+			       N_("select files by diff type"),
+			       PARSE_OPT_NONEG, diff_opt_diff_filter),
 		{ OPTION_CALLBACK, 0, "output", options, N_("<file>"),
 		  N_("Output to a specific file"),
 		  PARSE_OPT_NONEG, NULL, 0, diff_opt_output },
@@ -5441,13 +5448,6 @@ int diff_opt_parse(struct diff_options *options,
 	}
 
 	/* misc options */
-	else if ((argcount = parse_long_opt("diff-filter", av, &optarg))) {
-		int offending = parse_diff_filter_opt(optarg, options);
-		if (offending)
-			die("unknown change class '%c' in --diff-filter=%s",
-			    offending, optarg);
-		return argcount;
-	}
 	else if (!strcmp(arg, "--no-abbrev"))
 		options->abbrev = 0;
 	else if (!strcmp(arg, "--abbrev"))