diff --git a/builtin/add.c b/builtin/add.c
index 12c5aa6d1f..c27254a5cd 100644
--- a/builtin/add.c
+++ b/builtin/add.c
@@ -231,6 +231,8 @@ static char *chmod_arg;
 
 static int ignore_removal_cb(const struct option *opt, const char *arg, int unset)
 {
+	BUG_ON_OPT_ARG(arg);
+
 	/* if we are told to ignore, we are not adding removals */
 	*(int *)opt->value = !unset ? 0 : 1;
 	return 0;
diff --git a/builtin/checkout-index.c b/builtin/checkout-index.c
index f62f13f2b5..3b68b47615 100644
--- a/builtin/checkout-index.c
+++ b/builtin/checkout-index.c
@@ -24,7 +24,7 @@
 static int nul_term_line;
 static int checkout_stage; /* default to checkout stage0 */
 static int ignore_skip_worktree; /* default to 0 */
-static int to_tempfile;
+static int to_tempfile = -1;
 static char topath[4][TEMPORARY_FILENAME_LENGTH + 1];
 
 static struct checkout state = CHECKOUT_INIT;
@@ -193,15 +193,16 @@ static const char * const builtin_checkout_index_usage[] = {
 static int option_parse_stage(const struct option *opt,
 			      const char *arg, int unset)
 {
+	int *stage = opt->value;
+
 	BUG_ON_OPT_NEG(unset);
 
 	if (!strcmp(arg, "all")) {
-		to_tempfile = 1;
-		checkout_stage = CHECKOUT_ALL;
+		*stage = CHECKOUT_ALL;
 	} else {
 		int ch = arg[0];
 		if ('1' <= ch && ch <= '3')
-			checkout_stage = arg[0] - '0';
+			*stage = arg[0] - '0';
 		else
 			die(_("stage should be between 1 and 3 or all"));
 	}
@@ -239,7 +240,7 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 			N_("write the content to temporary files")),
 		OPT_STRING(0, "prefix", &state.base_dir, N_("string"),
 			N_("when creating files, prepend <string>")),
-		OPT_CALLBACK_F(0, "stage", NULL, "(1|2|3|all)",
+		OPT_CALLBACK_F(0, "stage", &checkout_stage, "(1|2|3|all)",
 			N_("copy out the files from named stage"),
 			PARSE_OPT_NONEG, option_parse_stage),
 		OPT_END()
@@ -269,6 +270,12 @@ int cmd_checkout_index(int argc, const char **argv, const char *prefix)
 		state.base_dir = "";
 	state.base_dir_len = strlen(state.base_dir);
 
+	if (to_tempfile < 0)
+		to_tempfile = (checkout_stage == CHECKOUT_ALL);
+	if (!to_tempfile && checkout_stage == CHECKOUT_ALL)
+		die(_("options '%s' and '%s' cannot be used together"),
+		    "--stage=all", "--no-temp");
+
 	/*
 	 * when --prefix is specified we do not want to update cache.
 	 */
diff --git a/builtin/describe.c b/builtin/describe.c
index a9e375882b..fb6b0508f3 100644
--- a/builtin/describe.c
+++ b/builtin/describe.c
@@ -561,9 +561,11 @@ static void describe(const char *arg, int last_one)
 static int option_parse_exact_match(const struct option *opt, const char *arg,
 				    int unset)
 {
+	int *val = opt->value;
+
 	BUG_ON_OPT_ARG(arg);
 
-	max_candidates = unset ? DEFAULT_CANDIDATES : 0;
+	*val = unset ? DEFAULT_CANDIDATES : 0;
 	return 0;
 }
 
@@ -578,7 +580,7 @@ int cmd_describe(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "long",       &longformat, N_("always use long format")),
 		OPT_BOOL(0, "first-parent", &first_parent, N_("only follow first parent")),
 		OPT__ABBREV(&abbrev),
-		OPT_CALLBACK_F(0, "exact-match", NULL, NULL,
+		OPT_CALLBACK_F(0, "exact-match", &max_candidates, NULL,
 			       N_("only output exact matches"),
 			       PARSE_OPT_NOARG, option_parse_exact_match),
 		OPT_INTEGER(0, "candidates", &max_candidates,
diff --git a/builtin/fast-export.c b/builtin/fast-export.c
index 56dc69fac1..70aff515ac 100644
--- a/builtin/fast-export.c
+++ b/builtin/fast-export.c
@@ -33,9 +33,9 @@ static const char *fast_export_usage[] = {
 };
 
 static int progress;
-static enum { SIGNED_TAG_ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = SIGNED_TAG_ABORT;
-static enum { TAG_FILTERING_ABORT, DROP, REWRITE } tag_of_filtered_mode = TAG_FILTERING_ABORT;
-static enum { REENCODE_ABORT, REENCODE_YES, REENCODE_NO } reencode_mode = REENCODE_ABORT;
+static enum signed_tag_mode { SIGNED_TAG_ABORT, VERBATIM, WARN, WARN_STRIP, STRIP } signed_tag_mode = SIGNED_TAG_ABORT;
+static enum tag_of_filtered_mode { TAG_FILTERING_ABORT, DROP, REWRITE } tag_of_filtered_mode = TAG_FILTERING_ABORT;
+static enum reencode_mode { REENCODE_ABORT, REENCODE_YES, REENCODE_NO } reencode_mode = REENCODE_ABORT;
 static int fake_missing_tagger;
 static int use_done_feature;
 static int no_data;
@@ -53,16 +53,18 @@ static struct revision_sources revision_sources;
 static int parse_opt_signed_tag_mode(const struct option *opt,
 				     const char *arg, int unset)
 {
+	enum signed_tag_mode *val = opt->value;
+
 	if (unset || !strcmp(arg, "abort"))
-		signed_tag_mode = SIGNED_TAG_ABORT;
+		*val = SIGNED_TAG_ABORT;
 	else if (!strcmp(arg, "verbatim") || !strcmp(arg, "ignore"))
-		signed_tag_mode = VERBATIM;
+		*val = VERBATIM;
 	else if (!strcmp(arg, "warn"))
-		signed_tag_mode = WARN;
+		*val = WARN;
 	else if (!strcmp(arg, "warn-strip"))
-		signed_tag_mode = WARN_STRIP;
+		*val = WARN_STRIP;
 	else if (!strcmp(arg, "strip"))
-		signed_tag_mode = STRIP;
+		*val = STRIP;
 	else
 		return error("Unknown signed-tags mode: %s", arg);
 	return 0;
@@ -71,12 +73,14 @@ static int parse_opt_signed_tag_mode(const struct option *opt,
 static int parse_opt_tag_of_filtered_mode(const struct option *opt,
 					  const char *arg, int unset)
 {
+	enum tag_of_filtered_mode *val = opt->value;
+
 	if (unset || !strcmp(arg, "abort"))
-		tag_of_filtered_mode = TAG_FILTERING_ABORT;
+		*val = TAG_FILTERING_ABORT;
 	else if (!strcmp(arg, "drop"))
-		tag_of_filtered_mode = DROP;
+		*val = DROP;
 	else if (!strcmp(arg, "rewrite"))
-		tag_of_filtered_mode = REWRITE;
+		*val = REWRITE;
 	else
 		return error("Unknown tag-of-filtered mode: %s", arg);
 	return 0;
@@ -85,21 +89,23 @@ static int parse_opt_tag_of_filtered_mode(const struct option *opt,
 static int parse_opt_reencode_mode(const struct option *opt,
 				   const char *arg, int unset)
 {
+	enum reencode_mode *val = opt->value;
+
 	if (unset) {
-		reencode_mode = REENCODE_ABORT;
+		*val = REENCODE_ABORT;
 		return 0;
 	}
 
 	switch (git_parse_maybe_bool(arg)) {
 	case 0:
-		reencode_mode = REENCODE_NO;
+		*val = REENCODE_NO;
 		break;
 	case 1:
-		reencode_mode = REENCODE_YES;
+		*val = REENCODE_YES;
 		break;
 	default:
 		if (!strcasecmp(arg, "abort"))
-			reencode_mode = REENCODE_ABORT;
+			*val = REENCODE_ABORT;
 		else
 			return error("Unknown reencoding mode: %s", arg);
 	}
diff --git a/builtin/fetch.c b/builtin/fetch.c
index 8f93529505..fd134ba74d 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -176,7 +176,7 @@ static int parse_refmap_arg(const struct option *opt, const char *arg, int unset
 	 * "git fetch --refmap='' origin foo"
 	 * can be used to tell the command not to store anywhere
 	 */
-	refspec_append(&refmap, arg);
+	refspec_append(opt->value, arg);
 
 	return 0;
 }
@@ -2204,7 +2204,7 @@ int cmd_fetch(int argc, const char **argv, const char *prefix)
 			   PARSE_OPT_HIDDEN, option_fetch_parse_recurse_submodules),
 		OPT_BOOL(0, "update-shallow", &update_shallow,
 			 N_("accept refs that update .git/shallow")),
-		OPT_CALLBACK_F(0, "refmap", NULL, N_("refmap"),
+		OPT_CALLBACK_F(0, "refmap", &refmap, N_("refmap"),
 			       N_("specify fetch refmap"), PARSE_OPT_NONEG, parse_refmap_arg),
 		OPT_STRING_LIST('o', "server-option", &server_options, N_("server-specific"), N_("option to transmit")),
 		OPT_IPVERSION(&family),
diff --git a/builtin/gc.c b/builtin/gc.c
index 369bd43fb2..b842349d86 100644
--- a/builtin/gc.c
+++ b/builtin/gc.c
@@ -1403,7 +1403,7 @@ static void initialize_task_config(int schedule)
 	strbuf_release(&config_name);
 }
 
-static int task_option_parse(const struct option *opt,
+static int task_option_parse(const struct option *opt UNUSED,
 			     const char *arg, int unset)
 {
 	int i, num_selected = 0;
diff --git a/builtin/interpret-trailers.c b/builtin/interpret-trailers.c
index c5e8345265..a110e69f83 100644
--- a/builtin/interpret-trailers.c
+++ b/builtin/interpret-trailers.c
@@ -24,21 +24,24 @@ static enum trailer_if_exists if_exists;
 static enum trailer_if_missing if_missing;
 
 static int option_parse_where(const struct option *opt,
-			      const char *arg, int unset)
+			      const char *arg, int unset UNUSED)
 {
-	return trailer_set_where(&where, arg);
+	/* unset implies NULL arg, which is handled in our helper */
+	return trailer_set_where(opt->value, arg);
 }
 
 static int option_parse_if_exists(const struct option *opt,
-				  const char *arg, int unset)
+				  const char *arg, int unset UNUSED)
 {
-	return trailer_set_if_exists(&if_exists, arg);
+	/* unset implies NULL arg, which is handled in our helper */
+	return trailer_set_if_exists(opt->value, arg);
 }
 
 static int option_parse_if_missing(const struct option *opt,
-				   const char *arg, int unset)
+				   const char *arg, int unset UNUSED)
 {
-	return trailer_set_if_missing(&if_missing, arg);
+	/* unset implies NULL arg, which is handled in our helper */
+	return trailer_set_if_missing(opt->value, arg);
 }
 
 static void new_trailers_clear(struct list_head *trailers)
@@ -97,11 +100,11 @@ int cmd_interpret_trailers(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "in-place", &opts.in_place, N_("edit files in place")),
 		OPT_BOOL(0, "trim-empty", &opts.trim_empty, N_("trim empty trailers")),
 
-		OPT_CALLBACK(0, "where", NULL, N_("action"),
+		OPT_CALLBACK(0, "where", &where, N_("action"),
 			     N_("where to place the new trailer"), option_parse_where),
-		OPT_CALLBACK(0, "if-exists", NULL, N_("action"),
+		OPT_CALLBACK(0, "if-exists", &if_exists, N_("action"),
 			     N_("action if trailer already exists"), option_parse_if_exists),
-		OPT_CALLBACK(0, "if-missing", NULL, N_("action"),
+		OPT_CALLBACK(0, "if-missing", &if_missing, N_("action"),
 			     N_("action if trailer is missing"), option_parse_if_missing),
 
 		OPT_BOOL(0, "only-trailers", &opts.only_trailers, N_("output only the trailers")),
diff --git a/builtin/log.c b/builtin/log.c
index 195cd46cdc..b085417942 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -118,16 +118,19 @@ static struct string_list decorate_refs_exclude = STRING_LIST_INIT_NODUP;
 static struct string_list decorate_refs_exclude_config = STRING_LIST_INIT_NODUP;
 static struct string_list decorate_refs_include = STRING_LIST_INIT_NODUP;
 
-static int clear_decorations_callback(const struct option *opt,
-					    const char *arg, int unset)
+static int clear_decorations_callback(const struct option *opt UNUSED,
+				      const char *arg, int unset)
 {
+	BUG_ON_OPT_NEG(unset);
+	BUG_ON_OPT_ARG(arg);
 	string_list_clear(&decorate_refs_include, 0);
 	string_list_clear(&decorate_refs_exclude, 0);
 	use_default_decoration_filter = 0;
 	return 0;
 }
 
-static int decorate_callback(const struct option *opt, const char *arg, int unset)
+static int decorate_callback(const struct option *opt UNUSED, const char *arg,
+			     int unset)
 {
 	if (unset)
 		decoration_style = 0;
@@ -1564,7 +1567,8 @@ static int inline_callback(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-static int header_callback(const struct option *opt, const char *arg, int unset)
+static int header_callback(const struct option *opt UNUSED, const char *arg,
+			   int unset)
 {
 	if (unset) {
 		string_list_clear(&extra_hdr, 0);
@@ -1576,24 +1580,6 @@ static int header_callback(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-static int to_callback(const struct option *opt, const char *arg, int unset)
-{
-	if (unset)
-		string_list_clear(&extra_to, 0);
-	else
-		string_list_append(&extra_to, arg);
-	return 0;
-}
-
-static int cc_callback(const struct option *opt, const char *arg, int unset)
-{
-	if (unset)
-		string_list_clear(&extra_cc, 0);
-	else
-		string_list_append(&extra_cc, arg);
-	return 0;
-}
-
 static int from_callback(const struct option *opt, const char *arg, int unset)
 {
 	char **from = opt->value;
@@ -1968,8 +1954,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		OPT_GROUP(N_("Messaging")),
 		OPT_CALLBACK(0, "add-header", NULL, N_("header"),
 			    N_("add email header"), header_callback),
-		OPT_CALLBACK(0, "to", NULL, N_("email"), N_("add To: header"), to_callback),
-		OPT_CALLBACK(0, "cc", NULL, N_("email"), N_("add Cc: header"), cc_callback),
+		OPT_STRING_LIST(0, "to", &extra_to, N_("email"), N_("add To: header")),
+		OPT_STRING_LIST(0, "cc", &extra_cc, N_("email"), N_("add Cc: header")),
 		OPT_CALLBACK_F(0, "from", &from, N_("ident"),
 			    N_("set From address to <ident> (or committer ident if absent)"),
 			    PARSE_OPT_OPTARG, from_callback),
diff --git a/builtin/merge.c b/builtin/merge.c
index de68910177..545da0c8a1 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -79,8 +79,7 @@ static int overwrite_ignore = 1;
 static struct strbuf merge_msg = STRBUF_INIT;
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
-static const char **xopts;
-static size_t xopts_nr, xopts_alloc;
+static struct strvec xopts = STRVEC_INIT;
 static const char *branch;
 static char *branch_mergeoptions;
 static int verbosity;
@@ -232,7 +231,7 @@ static void append_strategy(struct strategy *s)
 	use_strategies[use_strategies_nr++] = s;
 }
 
-static int option_parse_strategy(const struct option *opt,
+static int option_parse_strategy(const struct option *opt UNUSED,
 				 const char *name, int unset)
 {
 	if (unset)
@@ -242,29 +241,9 @@ static int option_parse_strategy(const struct option *opt,
 	return 0;
 }
 
-static int option_parse_x(const struct option *opt,
-			  const char *arg, int unset)
-{
-	if (unset)
-		return 0;
-
-	ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
-	xopts[xopts_nr++] = xstrdup(arg);
-	return 0;
-}
-
-static int option_parse_n(const struct option *opt,
-			  const char *arg, int unset)
-{
-	BUG_ON_OPT_ARG(arg);
-	show_diffstat = unset;
-	return 0;
-}
-
 static struct option builtin_merge_options[] = {
-	OPT_CALLBACK_F('n', NULL, NULL, NULL,
-		N_("do not show a diffstat at the end of the merge"),
-		PARSE_OPT_NOARG, option_parse_n),
+	OPT_SET_INT('n', NULL, &show_diffstat,
+		N_("do not show a diffstat at the end of the merge"), 0),
 	OPT_BOOL(0, "stat", &show_diffstat,
 		N_("show a diffstat at the end of the merge")),
 	OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
@@ -285,10 +264,10 @@ static struct option builtin_merge_options[] = {
 	OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 	OPT_BOOL(0, "verify-signatures", &verify_signatures,
 		N_("verify that the named commit has a valid GPG signature")),
-	OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
+	OPT_CALLBACK('s', "strategy", NULL, N_("strategy"),
 		N_("merge strategy to use"), option_parse_strategy),
-	OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
-		N_("option for selected merge strategy"), option_parse_x),
+	OPT_STRVEC('X', "strategy-option", &xopts, N_("option=value"),
+		N_("option for selected merge strategy")),
 	OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
 		N_("merge commit message (for a non-fast-forward merge)"),
 		option_parse_message),
@@ -749,9 +728,9 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		o.show_rename_progress =
 			show_progress == -1 ? isatty(2) : show_progress;
 
-		for (x = 0; x < xopts_nr; x++)
-			if (parse_merge_opt(&o, xopts[x]))
-				die(_("unknown strategy option: -X%s"), xopts[x]);
+		for (x = 0; x < xopts.nr; x++)
+			if (parse_merge_opt(&o, xopts.v[x]))
+				die(_("unknown strategy option: -X%s"), xopts.v[x]);
 
 		o.branch1 = head_arg;
 		o.branch2 = merge_remote_util(remoteheads->item)->name;
@@ -777,7 +756,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		return clean ? 0 : 1;
 	} else {
 		return try_merge_command(the_repository,
-					 strategy, xopts_nr, xopts,
+					 strategy, xopts.nr, xopts.v,
 					 common, head_arg, remoteheads);
 	}
 }
diff --git a/builtin/pack-objects.c b/builtin/pack-objects.c
index 72241bdca4..6eb9756836 100644
--- a/builtin/pack-objects.c
+++ b/builtin/pack-objects.c
@@ -3738,7 +3738,7 @@ static void show_object__ma_allow_promisor(struct object *obj, const char *name,
 	show_object(obj, name, data);
 }
 
-static int option_parse_missing_action(const struct option *opt,
+static int option_parse_missing_action(const struct option *opt UNUSED,
 				       const char *arg, int unset)
 {
 	assert(arg);
@@ -4119,34 +4119,37 @@ static void add_extra_kept_packs(const struct string_list *names)
 static int option_parse_quiet(const struct option *opt, const char *arg,
 			      int unset)
 {
+	int *val = opt->value;
+
 	BUG_ON_OPT_ARG(arg);
 
 	if (!unset)
-		progress = 0;
-	else if (!progress)
-		progress = 1;
+		*val = 0;
+	else if (!*val)
+		*val = 1;
 	return 0;
 }
 
 static int option_parse_index_version(const struct option *opt,
 				      const char *arg, int unset)
 {
+	struct pack_idx_option *popts = opt->value;
 	char *c;
 	const char *val = arg;
 
 	BUG_ON_OPT_NEG(unset);
 
-	pack_idx_opts.version = strtoul(val, &c, 10);
-	if (pack_idx_opts.version > 2)
+	popts->version = strtoul(val, &c, 10);
+	if (popts->version > 2)
 		die(_("unsupported index version %s"), val);
 	if (*c == ',' && c[1])
-		pack_idx_opts.off32_limit = strtoul(c+1, &c, 0);
-	if (*c || pack_idx_opts.off32_limit & 0x80000000)
+		popts->off32_limit = strtoul(c+1, &c, 0);
+	if (*c || popts->off32_limit & 0x80000000)
 		die(_("bad index version '%s'"), val);
 	return 0;
 }
 
-static int option_parse_unpack_unreachable(const struct option *opt,
+static int option_parse_unpack_unreachable(const struct option *opt UNUSED,
 					   const char *arg, int unset)
 {
 	if (unset) {
@@ -4161,7 +4164,7 @@ static int option_parse_unpack_unreachable(const struct option *opt,
 	return 0;
 }
 
-static int option_parse_cruft_expiration(const struct option *opt,
+static int option_parse_cruft_expiration(const struct option *opt UNUSED,
 					 const char *arg, int unset)
 {
 	if (unset) {
@@ -4189,7 +4192,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		LIST_OBJECTS_FILTER_INIT;
 
 	struct option pack_objects_options[] = {
-		OPT_CALLBACK_F('q', "quiet", NULL, NULL,
+		OPT_CALLBACK_F('q', "quiet", &progress, NULL,
 			       N_("do not show progress meter"),
 			       PARSE_OPT_NOARG, option_parse_quiet),
 		OPT_SET_INT(0, "progress", &progress,
@@ -4199,7 +4202,7 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
 		OPT_BOOL(0, "all-progress-implied",
 			 &all_progress_implied,
 			 N_("similar to --all-progress when progress meter is shown")),
-		OPT_CALLBACK_F(0, "index-version", NULL, N_("<version>[,<offset>]"),
+		OPT_CALLBACK_F(0, "index-version", &pack_idx_opts, N_("<version>[,<offset>]"),
 		  N_("write the pack index file in the specified idx format version"),
 		  PARSE_OPT_NONEG, option_parse_index_version),
 		OPT_MAGNITUDE(0, "max-pack-size", &pack_size_limit,
diff --git a/builtin/read-tree.c b/builtin/read-tree.c
index 1fec702a04..8196ca9dd8 100644
--- a/builtin/read-tree.c
+++ b/builtin/read-tree.c
@@ -49,7 +49,7 @@ static const char * const read_tree_usage[] = {
 	NULL
 };
 
-static int index_output_cb(const struct option *opt, const char *arg,
+static int index_output_cb(const struct option *opt UNUSED, const char *arg,
 				 int unset)
 {
 	BUG_ON_OPT_NEG(unset);
diff --git a/builtin/update-index.c b/builtin/update-index.c
index aee3cb8cbd..59acae3336 100644
--- a/builtin/update-index.c
+++ b/builtin/update-index.c
@@ -856,7 +856,7 @@ static int chmod_callback(const struct option *opt,
 	return 0;
 }
 
-static int resolve_undo_clear_callback(const struct option *opt,
+static int resolve_undo_clear_callback(const struct option *opt UNUSED,
 				const char *arg, int unset)
 {
 	BUG_ON_OPT_NEG(unset);
@@ -890,7 +890,7 @@ static int parse_new_style_cacheinfo(const char *arg,
 }
 
 static enum parse_opt_result cacheinfo_callback(
-	struct parse_opt_ctx_t *ctx, const struct option *opt,
+	struct parse_opt_ctx_t *ctx, const struct option *opt UNUSED,
 	const char *arg, int unset)
 {
 	struct object_id oid;
diff --git a/parse-options-cb.c b/parse-options-cb.c
index a24521dee0..bdc7fae497 100644
--- a/parse-options-cb.c
+++ b/parse-options-cb.c
@@ -227,7 +227,9 @@ int parse_opt_strvec(const struct option *opt, const char *arg, int unset)
 	return 0;
 }
 
-int parse_opt_noop_cb(const struct option *opt, const char *arg, int unset)
+int parse_opt_noop_cb(const struct option *opt UNUSED,
+		      const char *arg UNUSED,
+		      int unset UNUSED)
 {
 	return 0;
 }
diff --git a/t/t2004-checkout-cache-temp.sh b/t/t2004-checkout-cache-temp.sh
index b16d69ca4a..45dd1bc858 100755
--- a/t/t2004-checkout-cache-temp.sh
+++ b/t/t2004-checkout-cache-temp.sh
@@ -117,6 +117,26 @@ test_expect_success 'checkout all stages/one file to temporary files' '
 	test $(cat $s3) = tree3path1)
 '
 
+test_expect_success '--stage=all implies --temp' '
+	rm -f path* .merge_* actual &&
+	git checkout-index --stage=all -- path1 &&
+	test_path_is_missing path1
+'
+
+test_expect_success 'overriding --stage=all resets implied --temp' '
+	rm -f path* .merge_* actual &&
+	git checkout-index --stage=all --stage=2 -- path1 &&
+	echo tree2path1 >expect &&
+	test_cmp expect path1
+'
+
+test_expect_success '--stage=all --no-temp is rejected' '
+	rm -f path* .merge_* actual &&
+	test_must_fail git checkout-index --stage=all --no-temp -- path1 2>err &&
+	grep -v "already exists" err &&
+	grep "options .--stage=all. and .--no-temp. cannot be used together" err
+'
+
 test_expect_success 'checkout some stages/one file to temporary files' '
 	rm -f path* .merge_* actual &&
 	git checkout-index --stage=all --temp -- path2 >actual &&