diff --git a/common/test/run-channel_type.c b/common/test/run-channel_type.c
index 9e2bea287343..46edef12b3ee 100644
--- a/common/test/run-channel_type.c
+++ b/common/test/run-channel_type.c
@@ -4,6 +4,7 @@
 #include <ccan/tal/str/str.h>
 #include <common/setup.h>
 #include <stdio.h>
+#include <lightningd/channel_state.h>
 
 /* AUTOGENERATED MOCKS START */
 /* Generated stub for amount_asset_is_main */
@@ -114,6 +115,39 @@ static void assert_names_eq(const char **names, const char *expected)
 		assert(streq(expected_names[i], names[i]));
 }
 
+static enum channel_state calc_channel_state_max(void)
+{
+	enum channel_state largest_state = 0;
+
+	assert(DUALOPEND_OPEN_INIT == 1);
+	for (enum channel_state state = 1;; state++) {
+		bool known_state = false;
+		switch(state) {
+			case DUALOPEND_OPEN_INIT:
+			case CHANNELD_AWAITING_LOCKIN:
+			case CHANNELD_NORMAL:
+			case CHANNELD_SHUTTING_DOWN:
+			case CLOSINGD_SIGEXCHANGE:
+			case CLOSINGD_COMPLETE:
+			case AWAITING_UNILATERAL:
+			case FUNDING_SPEND_SEEN:
+			case ONCHAIN:
+			case CLOSED:
+			case DUALOPEND_OPEN_COMMITTED:
+			case DUALOPEND_AWAITING_LOCKIN:
+			case CHANNELD_AWAITING_SPLICE:
+			case DUALOPEND_OPEN_COMMIT_READY:
+				largest_state = state;
+				known_state = true;
+				break;
+		}
+		if (!known_state)
+			break;
+	}
+
+	return largest_state;
+}
+
 int main(int argc, char *argv[])
 {
 	struct channel_type t;
@@ -125,6 +159,8 @@ int main(int argc, char *argv[])
 	assert_names_eq(channel_type_name(tmpctx, channel_type_anchors_zero_fee_htlc(tmpctx)),
 			"static_remotekey/even anchors/even");
 
+	assert(calc_channel_state_max() == CHANNEL_STATE_MAX);
+
 	t.features = tal_arr(tmpctx, u8, 0);
 	set_feature_bit(&t.features, 1000);
 	assert_names_eq(channel_type_name(tmpctx, &t), "unknown_1000/even");
diff --git a/lightningd/channel_state.h b/lightningd/channel_state.h
index 8ef3da3bebe7..26d12d81d6df 100644
--- a/lightningd/channel_state.h
+++ b/lightningd/channel_state.h
@@ -50,7 +50,7 @@ enum channel_state {
 	DUALOPEND_OPEN_COMMIT_READY,
 
 };
-#define CHANNEL_STATE_MAX CHANNELD_AWAITING_SPLICE
+#define CHANNEL_STATE_MAX DUALOPEND_OPEN_COMMIT_READY
 
 /* These are in the database, so don't renumber them! */
 enum state_change {