From: Ondřej Surý <ondrej@sury.org>
Date: Mon, 11 Oct 2021 10:50:17 +0000 (+0200)
Subject: Simplify way we tag unreachable code with only ISC_UNREACHABLE()
X-Git-Tag: v9.19.0~48^2~3
X-Git-Url: http://git.ipfire.org/gitweb/?a=commitdiff_plain;h=584f0d7a7e89f4681b78dee157f7a2807812023a;p=thirdparty%2Fbind9.git

Simplify way we tag unreachable code with only ISC_UNREACHABLE()

Previously, the unreachable code paths would have to be tagged with:

    INSIST(0);
    ISC_UNREACHABLE();

There was also older parts of the code that used comment annotation:

    /* NOTREACHED */

Unify the handling of unreachable code paths to just use:

    UNREACHABLE();

The UNREACHABLE() macro now asserts when reached and also uses
__builtin_unreachable(); when such builtin is available in the compiler.
---

diff --git a/bin/check/named-checkconf.c b/bin/check/named-checkconf.c
index 0594ed157e3..06fd59cb8d2 100644
--- a/bin/check/named-checkconf.c
+++ b/bin/check/named-checkconf.c
@@ -306,8 +306,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 			zone_options &= ~DNS_ZONEOPT_CHECKDUPRR;
 			zone_options &= ~DNS_ZONEOPT_CHECKDUPRRFAIL;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_CHECKDUPRR;
@@ -326,8 +325,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 			zone_options &= ~DNS_ZONEOPT_CHECKMX;
 			zone_options &= ~DNS_ZONEOPT_CHECKMXFAIL;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_CHECKMX;
@@ -357,8 +355,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 			zone_options |= DNS_ZONEOPT_WARNMXCNAME;
 			zone_options |= DNS_ZONEOPT_IGNOREMXCNAME;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_WARNMXCNAME;
@@ -377,8 +374,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 			zone_options |= DNS_ZONEOPT_WARNSRVCNAME;
 			zone_options |= DNS_ZONEOPT_IGNORESRVCNAME;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_WARNSRVCNAME;
@@ -401,8 +397,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			zone_options &= ~DNS_ZONEOPT_CHECKSPF;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_CHECKSPF;
@@ -420,8 +415,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 			zone_options &= ~DNS_ZONEOPT_CHECKNAMES;
 			zone_options &= ~DNS_ZONEOPT_CHECKNAMESFAIL;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		zone_options |= DNS_ZONEOPT_CHECKNAMES;
@@ -437,8 +431,7 @@ configure_zone(const char *vclass, const char *view, const cfg_obj_t *zconfig,
 		} else if (strcasecmp(masterformatstr, "raw") == 0) {
 			masterformat = dns_masterformat_raw;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
diff --git a/bin/check/named-checkzone.c b/bin/check/named-checkzone.c
index 80cdfb55d38..ffee5bcd776 100644
--- a/bin/check/named-checkzone.c
+++ b/bin/check/named-checkzone.c
@@ -147,8 +147,7 @@ main(int argc, char **argv) {
 	} else if (PROGCMP("named-compilezone")) {
 		progmode = progmode_compile;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/* Compilation specific defaults */
diff --git a/bin/confgen/tsig-keygen.c b/bin/confgen/tsig-keygen.c
index a0d0764112f..b34d099faa7 100644
--- a/bin/confgen/tsig-keygen.c
+++ b/bin/confgen/tsig-keygen.c
@@ -121,8 +121,7 @@ main(int argc, char **argv) {
 	} else if (PROGCMP("ddns-confgen")) {
 		progmode = progmode_confgen;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc_commandline_errprint = false;
diff --git a/bin/delv/delv.c b/bin/delv/delv.c
index be77cb1f538..360b9839797 100644
--- a/bin/delv/delv.c
+++ b/bin/delv/delv.c
@@ -1325,7 +1325,7 @@ dash_option(char *option, char *next, bool *open_type_class) {
 		case 'h':
 			usage();
 			exit(0);
-		/* NOTREACHED */
+			UNREACHABLE();
 		case 'i':
 			no_sigs = true;
 			root_validation = false;
@@ -1336,10 +1336,9 @@ dash_option(char *option, char *next, bool *open_type_class) {
 		case 'v':
 			printf("delv %s\n", PACKAGE_VERSION);
 			exit(0);
-		/* NOTREACHED */
+			UNREACHABLE();
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		if (strlen(option) > 1U) {
 			option = &option[1];
@@ -1477,7 +1476,7 @@ dash_option(char *option, char *next, bool *open_type_class) {
 		fprintf(stderr, "Invalid option: -%s\n", option);
 		usage();
 	}
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (false);
 }
 
diff --git a/bin/dig/dig.c b/bin/dig/dig.c
index 4421df9d5db..7a7c648d8ec 100644
--- a/bin/dig/dig.c
+++ b/bin/dig/dig.c
@@ -2115,7 +2115,7 @@ dash_option(char *option, char *next, dig_lookup_t **lookup,
 				have_ipv6 = false;
 			} else {
 				fatal("can't find IPv4 networking");
-				/* NOTREACHED */
+				UNREACHABLE();
 				return (false);
 			}
 			break;
@@ -2125,7 +2125,7 @@ dash_option(char *option, char *next, dig_lookup_t **lookup,
 				have_ipv4 = false;
 			} else {
 				fatal("can't find IPv6 networking");
-				/* NOTREACHED */
+				UNREACHABLE();
 				return (false);
 			}
 			break;
@@ -2377,7 +2377,7 @@ dash_option(char *option, char *next, dig_lookup_t **lookup,
 		fprintf(stderr, "Invalid option: -%s\n", option);
 		usage();
 	}
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (false);
 }
 
diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index fa813901c7d..7b68d252ee5 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -2468,8 +2468,7 @@ setup_lookup(dig_lookup_t *lookup) {
 				memmove(addr, &sin6->sin6_addr, addrl);
 				break;
 			default:
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 
 			isc_buffer_init(&b, ecsbuf, sizeof(ecsbuf));
diff --git a/bin/dnssec/dnssec-keyfromlabel.c b/bin/dnssec/dnssec-keyfromlabel.c
index 233e12bc113..eca8f86b81c 100644
--- a/bin/dnssec/dnssec-keyfromlabel.c
+++ b/bin/dnssec/dnssec-keyfromlabel.c
@@ -616,7 +616,7 @@ main(int argc, char **argv) {
 		dns_secalg_format(alg, algstr, sizeof(algstr));
 		fatal("failed to get key %s/%s: %s", namestr, algstr,
 		      isc_result_totext(ret));
-		/* NOTREACHED */
+		UNREACHABLE();
 		exit(-1);
 	}
 
diff --git a/bin/dnssec/dnssec-signzone.c b/bin/dnssec/dnssec-signzone.c
index 207c861a5d5..2cceda3fce0 100644
--- a/bin/dnssec/dnssec-signzone.c
+++ b/bin/dnssec/dnssec-signzone.c
@@ -461,7 +461,7 @@ expecttofindkey(dns_name_t *name) {
 	dns_name_format(name, namestr, sizeof(namestr));
 	fatal("failure looking for '%s DNSKEY' in database: %s", namestr,
 	      isc_result_totext(result));
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (false); /* removes a warning */
 }
 
diff --git a/bin/dnssec/dnssectool.c b/bin/dnssec/dnssectool.c
index 38e21c7b764..c0d5d997911 100644
--- a/bin/dnssec/dnssectool.c
+++ b/bin/dnssec/dnssectool.c
@@ -217,7 +217,7 @@ time_units(isc_stdtime_t offset, char *suffix, const char *str) {
 		default:
 			fatal("time value %s is invalid", str);
 		}
-		/* NOTREACHED */
+		UNREACHABLE();
 		break;
 	case 'W':
 	case 'w':
@@ -235,7 +235,7 @@ time_units(isc_stdtime_t offset, char *suffix, const char *str) {
 	default:
 		fatal("time value %s is invalid", str);
 	}
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (0); /* silence compiler warning */
 }
 
diff --git a/bin/named/config.c b/bin/named/config.c
index e11163834d5..7c6ad5dc8b8 100644
--- a/bin/named/config.c
+++ b/bin/named/config.c
@@ -453,8 +453,7 @@ named_config_getzonetype(const cfg_obj_t *zonetypeobj) {
 	} else if (strcasecmp(str, "redirect") == 0) {
 		ztype = dns_zone_redirect;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (ztype);
 }
@@ -1066,8 +1065,7 @@ named_config_getkeyalgorithm2(const char *str, const dns_name_t **name,
 			*name = dns_tsig_hmacsha512_name;
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 	if (typep != NULL) {
diff --git a/bin/named/logconf.c b/bin/named/logconf.c
index af3b4045d91..5fd0904f43f 100644
--- a/bin/named/logconf.c
+++ b/bin/named/logconf.c
@@ -161,8 +161,7 @@ channel_fromconf(const cfg_obj_t *channel, isc_logconfig_t *logconfig) {
 			maxoffset = 0x7fffffffffffffffULL;
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		type = ISC_LOG_TOFILE;
diff --git a/bin/named/main.c b/bin/named/main.c
index e7ed4936127..bb4c08bb1ba 100644
--- a/bin/named/main.c
+++ b/bin/named/main.c
@@ -728,8 +728,7 @@ parse_port(char *arg) {
 		named_g_httpport = port;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/bin/named/server.c b/bin/named/server.c
index 19590f64496..831955fef1e 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -866,8 +866,7 @@ ta_fromconfig(const cfg_obj_t *key, bool *initialp, const char **namestrp,
 		break;
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	return (ISC_R_SUCCESS);
@@ -1273,8 +1272,7 @@ get_view_querysource_dispatch(const cfg_obj_t **maps, int af,
 		INSIST(result == ISC_R_SUCCESS);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	sa = *(cfg_obj_assockaddr(obj));
@@ -1296,8 +1294,7 @@ get_view_querysource_dispatch(const cfg_obj_t **maps, int af,
 		result = isc_net_probeipv6();
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	if (result != ISC_R_SUCCESS) {
 		return (ISC_R_SUCCESS);
@@ -1401,8 +1398,7 @@ configure_order(dns_order_t *order, const cfg_obj_t *ent) {
 	} else if (!strcasecmp(str, "none")) {
 		mode = DNS_RDATASETATTR_NONE;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
@@ -1558,8 +1554,7 @@ configure_peer(const cfg_obj_t *cpeer, isc_mem_t *mctx, dns_peer_t **peerp) {
 		} else if (strcasecmp(str, "one-answer") == 0) {
 			CHECK(dns_peer_settransferformat(peer, dns_one_answer));
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -2933,7 +2928,7 @@ catz_create_chg_task(dns_catz_entry_t *entry, dns_catz_zone_t *origin,
 		break;
 	default:
 		REQUIRE(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	event = (catz_chgzone_event_t *)isc_event_allocate(
@@ -4329,8 +4324,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 	} else if (strcasecmp(str, "ignore") == 0) {
 		view->checknames = false;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	obj = NULL;
@@ -4784,8 +4778,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 			} else if (strcasecmp(resp, "fail") == 0) {
 				r = DNS_R_SERVFAIL;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 
 			dns_resolver_setquotaresponse(view->resolver,
@@ -5184,8 +5177,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 		} else if (strcasecmp(str, "no-auth-recursive") == 0) {
 			view->minimalresponses = dns_minimal_noauthrec;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -5198,8 +5190,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 	} else if (strcasecmp(str, "one-answer") == 0) {
 		view->transfer_format = dns_one_answer;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	obj = NULL;
@@ -5511,8 +5502,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 		} else if (strcasecmp(resp, "fail") == 0) {
 			r = DNS_R_SERVFAIL;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		dns_resolver_setquotaresponse(view->resolver,
@@ -5739,8 +5729,7 @@ configure_view(dns_view_t *view, dns_viewlist_t *viewlist, cfg_obj_t *config,
 			} else if (strcasecmp(levelstr, "none") == 0) {
 				statlevel = dns_zonestat_none;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 		}
 
@@ -6281,8 +6270,7 @@ configure_forward(const cfg_obj_t *config, dns_view_t *view,
 			} else if (strcasecmp(forwardstr, "only") == 0) {
 				fwdpolicy = dns_fwdpolicy_only;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 		}
 	}
@@ -9575,8 +9563,7 @@ load_configuration(const char *filename, named_server_t *server,
 	} else if (strcasecmp(cfg_obj_asstring(obj), "aes") == 0) {
 		server->sctx->cookiealg = ns_cookiealg_aes;
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	obj = NULL;
@@ -13654,8 +13641,7 @@ newzone_parse(named_server_t *server, char *command, dns_view_t **viewp,
 	} else if (strncasecmp(command, "mod", 3) == 0) {
 		bn = "modzone";
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
@@ -16350,8 +16336,7 @@ named_server_mkeys(named_server_t *server, isc_lex_t *lex,
 			CHECK(mkey_destroy(server, view, text));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		if (viewtxt != NULL) {
diff --git a/bin/named/zoneconf.c b/bin/named/zoneconf.c
index 55f2f358543..9a363b30c31 100644
--- a/bin/named/zoneconf.c
+++ b/bin/named/zoneconf.c
@@ -133,8 +133,7 @@ configure_zone_acl(const cfg_obj_t *zconfig, const cfg_obj_t *vconfig,
 		aclname = "allow-update-forwarding";
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/* First check to see if ACL is defined within the zone */
@@ -246,8 +245,7 @@ configure_zone_ssutable(const cfg_obj_t *zconfig, dns_zone_t *zone,
 		} else if (strcasecmp(str, "deny") == 0) {
 			grant = false;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		str = cfg_obj_asstring(matchtype);
@@ -759,8 +757,7 @@ checknames(dns_zonetype_t ztype, const cfg_obj_t **maps,
 		result = named_checknames_get(maps, primary_synonyms, objp);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	INSIST(result == ISC_R_SUCCESS && objp != NULL && *objp != NULL);
@@ -1041,8 +1038,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(masterformatstr, "raw") == 0) {
 			masterformat = dns_masterformat_raw;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -1065,8 +1061,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(masterstylestr, "relative") == 0) {
 			masterstyle = &dns_master_style_default;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -1159,8 +1154,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(dialupstr, "passive") == 0) {
 			dialup = dns_dialuptype_passive;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 	if (raw != NULL) {
@@ -1186,8 +1180,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(levelstr, "none") == 0) {
 			statlevel = dns_zonestat_none;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 	dns_zone_setstatlevel(zone, statlevel);
@@ -1266,8 +1259,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 			{
 				notifytype = dns_notifytype_masteronly;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 		}
 		notifytype = process_notifytype(notifytype, ztype, zname,
@@ -1460,8 +1452,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			fail = check = false;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		if (raw != NULL) {
 			dns_zone_setoption(raw, DNS_ZONEOPT_CHECKNAMES, check);
@@ -1495,8 +1486,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			check = false;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		dns_zone_setoption(zone, DNS_ZONEOPT_CHECKSPF, check);
 
@@ -1696,8 +1686,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 			} else if (strcasecmp(arg, "off") == 0) {
 				/* Default */
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 			dns_zone_setkeyopt(zone, DNS_ZONEKEY_ALLOW, allow);
 			dns_zone_setkeyopt(zone, DNS_ZONEKEY_CREATE, false);
@@ -1756,8 +1745,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(dupcheck, "ignore") == 0) {
 			fail = check = false;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_CHECKDUPRR, check);
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_CHECKDUPRRFAIL, fail);
@@ -1773,8 +1761,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			fail = check = false;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_CHECKMX, check);
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_CHECKMXFAIL, fail);
@@ -1796,8 +1783,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			warn = ignore = true;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_WARNMXCNAME, warn);
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_IGNOREMXCNAME, ignore);
@@ -1813,8 +1799,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 		} else if (strcasecmp(cfg_obj_asstring(obj), "ignore") == 0) {
 			warn = ignore = true;
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_WARNSRVCNAME, warn);
 		dns_zone_setoption(mayberaw, DNS_ZONEOPT_IGNORESRVCNAME,
@@ -1837,8 +1822,7 @@ named_zone_configure(const cfg_obj_t *config, const cfg_obj_t *vconfig,
 			} else if (strcasecmp(arg, "maintain") == 0) {
 				/* Default */
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 		}
 
diff --git a/bin/rndc/rndc.c b/bin/rndc/rndc.c
index 178120d90d8..4c43e39ba00 100644
--- a/bin/rndc/rndc.c
+++ b/bin/rndc/rndc.c
@@ -592,8 +592,7 @@ rndc_startconnect(isc_sockaddr_t *addr) {
 		 */
 		fatal("UNIX domain sockets not currently supported");
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	atomic_fetch_add_relaxed(&connects, 1);
diff --git a/bin/tests/system/rpz/dnsrps.c b/bin/tests/system/rpz/dnsrps.c
index dfbe76147f8..4f8890873df 100644
--- a/bin/tests/system/rpz/dnsrps.c
+++ b/bin/tests/system/rpz/dnsrps.c
@@ -83,8 +83,7 @@ main(int argc, char **argv) {
 #ifdef USE_DNSRPS
 			printf("%s\n", librpz->dnsrpzd_path);
 #else  /* ifdef USE_DNSRPS */
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 #endif /* ifdef USE_DNSRPS */
 			return (0);
 
@@ -134,8 +133,7 @@ main(int argc, char **argv) {
 			librpz->client_detach(&client);
 			printf("%u\n", serial);
 #else  /* ifdef USE_DNSRPS */
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 #endif /* ifdef USE_DNSRPS */
 			return (0);
 
diff --git a/bin/tests/test_client.c b/bin/tests/test_client.c
index 5ba259087ec..bd5e543b6d5 100644
--- a/bin/tests/test_client.c
+++ b/bin/tests/test_client.c
@@ -432,8 +432,7 @@ run(void) {
 	} break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	waitforsignal();
diff --git a/bin/tests/test_server.c b/bin/tests/test_server.c
index affa92614e5..a5b88339637 100644
--- a/bin/tests/test_server.c
+++ b/bin/tests/test_server.c
@@ -302,8 +302,7 @@ run(void) {
 	} break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	REQUIRE(result == ISC_R_SUCCESS);
 
diff --git a/bin/tests/wire_test.c b/bin/tests/wire_test.c
index 3944e3b00b9..9f50981f046 100644
--- a/bin/tests/wire_test.c
+++ b/bin/tests/wire_test.c
@@ -58,7 +58,7 @@ fromhex(char c) {
 
 	fprintf(stderr, "bad input format: %02x\n", c);
 	exit(3);
-	/* NOTREACHED */
+	UNREACHABLE();
 }
 
 static void
diff --git a/bin/tools/mdig.c b/bin/tools/mdig.c
index a8dd85da38c..af395826b93 100644
--- a/bin/tools/mdig.c
+++ b/bin/tools/mdig.c
@@ -1698,7 +1698,7 @@ dash_option(const char *option, char *next, struct query *query, bool global,
 				have_ipv6 = false;
 			} else {
 				fatal("can't find IPv4 networking");
-				/* NOTREACHED */
+				UNREACHABLE();
 				return (false);
 			}
 			break;
@@ -1709,7 +1709,7 @@ dash_option(const char *option, char *next, struct query *query, bool global,
 				have_ipv4 = false;
 			} else {
 				fatal("can't find IPv6 networking");
-				/* NOTREACHED */
+				UNREACHABLE();
 				return (false);
 			}
 			break;
@@ -1817,7 +1817,7 @@ dash_option(const char *option, char *next, struct query *query, bool global,
 		fprintf(stderr, "Invalid option: -%s\n", option);
 		usage();
 	}
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (false);
 }
 
diff --git a/cocci/unreachable.spatch b/cocci/unreachable.spatch
index 0cc368a5164..100f1a0abe1 100644
--- a/cocci/unreachable.spatch
+++ b/cocci/unreachable.spatch
@@ -1,6 +1,13 @@
 @@
 @@
 
-    INSIST(0);
-+   ISC_UNREACHABLE();
-    ... when != ISC_UNREACHABLE();
+-   INSIST(0);
++   UNREACHABLE();
+    ... when != UNREACHABLE();
+
+@@
+@@
+
+-   INSIST(0);
+-   ISC_UNREACHABLE();
++   UNREACHABLE();
diff --git a/contrib/dlz/modules/wildcard/dlz_wildcard_dynamic.c b/contrib/dlz/modules/wildcard/dlz_wildcard_dynamic.c
index 9edcffe9ce1..3cb3ee1106d 100644
--- a/contrib/dlz/modules/wildcard/dlz_wildcard_dynamic.c
+++ b/contrib/dlz/modules/wildcard/dlz_wildcard_dynamic.c
@@ -699,7 +699,7 @@ fnmatch(const char *pattern, const char *string, int flags) {
 			break;
 		}
 	}
-	/* NOTREACHED */
+	UNREACHABLE();
 }
 
 static int
diff --git a/doc/dev/style.md b/doc/dev/style.md
index 3a71b859958..7551211c024 100644
--- a/doc/dev/style.md
+++ b/doc/dev/style.md
@@ -142,12 +142,10 @@ Good:
     	static char *	c	       /* Description of 'c'. */
 
 
-The following lint and lint-like comments should be used where appropriate:
+The following macros should be used where appropriate:
 
-    	/* ARGSUSED */
     	FALLTHROUGH;
-    	/* NOTREACHED */
-    	/* VARARGS */
+    	UNREACHABLE();
 
 #### Header files
 
diff --git a/lib/bind9/check.c b/lib/bind9/check.c
index 556bfb6faf8..5ced085ac4c 100644
--- a/lib/bind9/check.c
+++ b/lib/bind9/check.c
@@ -2654,8 +2654,7 @@ check_update_policy(const cfg_obj_t *policy, isc_log_t *logctx) {
 			}
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		for (element2 = cfg_list_first(typelist); element2 != NULL;
@@ -3054,8 +3053,7 @@ check_zoneconf(const cfg_obj_t *zconfig, const cfg_obj_t *voptions,
 			break;
 
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
diff --git a/lib/dns/acl.c b/lib/dns/acl.c
index 1dfbf33675c..f38ce3b64bd 100644
--- a/lib/dns/acl.c
+++ b/lib/dns/acl.c
@@ -464,8 +464,7 @@ dns_aclelement_match(const isc_netaddr_t *reqaddr, const dns_name_t *reqsigner,
 		return (dns_geoip_match(reqaddr, env->geoip, &e->geoip_elem));
 #endif /* if defined(HAVE_GEOIP2) */
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	result = dns_acl_match(reqaddr, reqsigner, inner, env, &indirectmatch,
@@ -658,8 +657,7 @@ dns_acl_isinsecure(const dns_acl_t *a) {
 			return (true);
 
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
diff --git a/lib/dns/diff.c b/lib/dns/diff.c
index 9c2a2516f73..f5f7cef11c9 100644
--- a/lib/dns/diff.c
+++ b/lib/dns/diff.c
@@ -372,8 +372,7 @@ diff_apply(dns_diff_t *diff, dns_db_t *db, dns_dbversion_t *ver, bool warn) {
 								 &ardataset);
 				break;
 			default:
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 
 			if (result == ISC_R_SUCCESS) {
diff --git a/lib/dns/dispatch.c b/lib/dns/dispatch.c
index 0fcac79d3c9..c7e683b9316 100644
--- a/lib/dns/dispatch.c
+++ b/lib/dns/dispatch.c
@@ -1543,8 +1543,7 @@ dispatch_getnext(dns_dispatch_t *disp, dns_dispentry_t *resp, int32_t timeout) {
 		break;
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -1710,8 +1709,7 @@ startrecv(isc_nmhandle_t *handle, dns_dispatch_t *disp, dns_dispentry_t *resp) {
 		break;
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -1838,8 +1836,7 @@ dns_dispatch_connect(dns_dispentry_t *resp) {
 			break;
 
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		break;
diff --git a/lib/dns/dnsrps.c b/lib/dns/dnsrps.c
index 9ff55b27a43..30b7052b3ed 100644
--- a/lib/dns/dnsrps.c
+++ b/lib/dns/dnsrps.c
@@ -311,8 +311,7 @@ dns_dnsrps_2policy(librpz_policy_t rps_policy) {
 	case LIBRPZ_POLICY_GIVEN:
 	case LIBRPZ_POLICY_DISABLED:
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/dns/dnstap.c b/lib/dns/dnstap.c
index 44e5f6e160e..e013ec27fab 100644
--- a/lib/dns/dnstap.c
+++ b/lib/dns/dnstap.c
@@ -635,8 +635,7 @@ dnstap_type(dns_dtmsgtype_t msgtype) {
 	case DNS_DTTYPE_UR:
 		return (DNSTAP__MESSAGE__TYPE__UPDATE_RESPONSE);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -985,8 +984,7 @@ dns_dt_open(const char *filename, dns_dtmode_t mode, isc_mem_t *mctx,
 		result = ISC_R_NOTIMPLEMENTED;
 		goto cleanup;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc_mem_attach(mctx, &handle->mctx);
diff --git a/lib/dns/ds.c b/lib/dns/ds.c
index 7b39d853001..22f158bd71e 100644
--- a/lib/dns/ds.c
+++ b/lib/dns/ds.c
@@ -63,8 +63,7 @@ dns_ds_fromkeyrdata(const dns_name_t *owner, dns_rdata_t *key,
 		break;
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	name = dns_fixedname_initname(&fname);
diff --git a/lib/dns/ecs.c b/lib/dns/ecs.c
index ae88c4713e1..8dbf720f64e 100644
--- a/lib/dns/ecs.c
+++ b/lib/dns/ecs.c
@@ -66,8 +66,7 @@ dns_ecs_equals(const dns_ecs_t *ecs1, const dns_ecs_t *ecs2) {
 		addr2 = (const unsigned char *)&ecs2->addr.type.in6;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
diff --git a/lib/dns/hmac_link.c b/lib/dns/hmac_link.c
index 244e1f15774..5764a0ff072 100644
--- a/lib/dns/hmac_link.c
+++ b/lib/dns/hmac_link.c
@@ -370,8 +370,7 @@ hmac__get_tag_key(const isc_md_type_t *type) {
 	} else if (type == ISC_MD_SHA512) {
 		return (TAG_HMACSHA512_KEY);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -390,8 +389,7 @@ hmac__get_tag_bits(const isc_md_type_t *type) {
 	} else if (type == ISC_MD_SHA512) {
 		return (TAG_HMACSHA512_BITS);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -443,8 +441,7 @@ hmac__to_dst_alg(const isc_md_type_t *type) {
 	} else if (type == ISC_MD_SHA512) {
 		return (DST_ALG_HMACSHA512);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/dns/journal.c b/lib/dns/journal.c
index 89ac28c4f92..d9aee371c6c 100644
--- a/lib/dns/journal.c
+++ b/lib/dns/journal.c
@@ -825,8 +825,7 @@ ixfr_order(const void *av, const void *bv) {
 		aop = 0;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	switch (b->op) {
@@ -839,8 +838,7 @@ ixfr_order(const void *av, const void *bv) {
 		bop = 0;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	r = bop - aop;
diff --git a/lib/dns/keymgr.c b/lib/dns/keymgr.c
index 6bc11dbb62c..660b8cd26f1 100644
--- a/lib/dns/keymgr.c
+++ b/lib/dns/keymgr.c
@@ -1366,8 +1366,7 @@ keymgr_transition_time(dns_dnsseckey_t *key, int type,
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 		break;
 	}
 
diff --git a/lib/dns/master.c b/lib/dns/master.c
index 020e4a1b8d3..a9cfe4d4fa5 100644
--- a/lib/dns/master.c
+++ b/lib/dns/master.c
@@ -540,8 +540,7 @@ loadctx_create(dns_masterformat_t format, isc_mem_t *mctx, unsigned int options,
 		lctx->load = load_raw;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (lex != NULL) {
diff --git a/lib/dns/masterdump.c b/lib/dns/masterdump.c
index ae2e815c866..e2743de8065 100644
--- a/lib/dns/masterdump.c
+++ b/lib/dns/masterdump.c
@@ -1580,8 +1580,7 @@ dumpctx_create(isc_mem_t *mctx, dns_db_t *db, dns_dbversion_t *version,
 		dctx->dumpsets = dump_rdatasets_raw;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	result = totext_ctx_init(style, NULL, &dctx->tctx);
@@ -1701,8 +1700,7 @@ writeheader(dns_dumpctx_t *dctx) {
 
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc_mem_put(dctx->mctx, buffer.base, buffer.length);
diff --git a/lib/dns/message.c b/lib/dns/message.c
index 04a33452262..31d92a96ca7 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -883,8 +883,7 @@ getname(dns_name_t *name, isc_buffer_t *source, dns_message_t *msg,
 		}
 	}
 
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 }
 
 static isc_result_t
diff --git a/lib/dns/name.c b/lib/dns/name.c
index 2a8f9a5d771..d9d55eb4f15 100644
--- a/lib/dns/name.c
+++ b/lib/dns/name.c
@@ -1475,7 +1475,7 @@ dns_name_totext2(const dns_name_t *name, unsigned int options,
 		} else {
 			FATAL_ERROR(__FILE__, __LINE__,
 				    "Unexpected label type %02x", count);
-			/* NOTREACHED */
+			UNREACHABLE();
 		}
 
 		/*
@@ -1599,7 +1599,7 @@ dns_name_tofilenametext(const dns_name_t *name, bool omit_final_dot,
 		} else {
 			FATAL_ERROR(__FILE__, __LINE__,
 				    "Unexpected label type %02x", count);
-			/* NOTREACHED */
+			UNREACHABLE();
 		}
 
 		/*
diff --git a/lib/dns/opensslecdsa_link.c b/lib/dns/opensslecdsa_link.c
index f1cb63eb0ef..519e88b7e7a 100644
--- a/lib/dns/opensslecdsa_link.c
+++ b/lib/dns/opensslecdsa_link.c
@@ -1153,8 +1153,7 @@ dst__key_to_eckey(dst_key_t *key, EC_KEY **eckey) {
 		group_nid = NID_secp384r1;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	*eckey = EC_KEY_new_by_curve_name(group_nid);
diff --git a/lib/dns/opensslrsa_link.c b/lib/dns/opensslrsa_link.c
index 2e39bf69e21..be1998e3819 100644
--- a/lib/dns/opensslrsa_link.c
+++ b/lib/dns/opensslrsa_link.c
@@ -83,8 +83,7 @@ opensslrsa_createctx(dst_key_t *key, dst_context_t *dctx) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	evp_md_ctx = EVP_MD_CTX_create();
@@ -104,8 +103,7 @@ opensslrsa_createctx(dst_key_t *key, dst_context_t *dctx) {
 		type = EVP_sha512();
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!EVP_DigestInit_ex(evp_md_ctx, type, NULL)) {
@@ -426,8 +424,7 @@ opensslrsa_generate(dst_key_t *key, int exp, void (*callback)(int)) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (exp == 0) {
diff --git a/lib/dns/peer.c b/lib/dns/peer.c
index 2ada8416558..bac2624e09f 100644
--- a/lib/dns/peer.c
+++ b/lib/dns/peer.c
@@ -251,8 +251,7 @@ dns_peer_new(isc_mem_t *mem, const isc_netaddr_t *addr, dns_peer_t **peerptr) {
 		prefixlen = 128;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	return (dns_peer_newprefix(mem, addr, prefixlen, peerptr));
diff --git a/lib/dns/rbt.c b/lib/dns/rbt.c
index 9ebe4e50f26..fd6fb1f4277 100644
--- a/lib/dns/rbt.c
+++ b/lib/dns/rbt.c
@@ -1805,8 +1805,7 @@ nexttable:
 	}
 
 	/* We haven't found any matching node, this should not be possible. */
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 }
 
 static inline void
diff --git a/lib/dns/rbtdb.c b/lib/dns/rbtdb.c
index 8757fbd5ab0..79c65ae9cea 100644
--- a/lib/dns/rbtdb.c
+++ b/lib/dns/rbtdb.c
@@ -4440,7 +4440,7 @@ zone_findzonecut(dns_db_t *db, const dns_name_t *name, unsigned int options,
 
 	FATAL_ERROR(__FILE__, __LINE__, "zone_findzonecut() called!");
 
-	/* NOTREACHED */
+	UNREACHABLE();
 	return (ISC_R_NOTIMPLEMENTED);
 }
 
@@ -7606,8 +7606,7 @@ nodecount(dns_db_t *db, dns_dbtree_t tree) {
 		count = dns_rbt_nodecount(rbtdb->nsec3);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	RWUNLOCK(&rbtdb->tree_lock, isc_rwlocktype_read);
 
diff --git a/lib/dns/rdata/generic/amtrelay_260.c b/lib/dns/rdata/generic/amtrelay_260.c
index 020cfcf06d8..54e08ba6629 100644
--- a/lib/dns/rdata/generic/amtrelay_260.c
+++ b/lib/dns/rdata/generic/amtrelay_260.c
@@ -116,8 +116,7 @@ fromtext_amtrelay(ARGS_FROMTEXT) {
 		return (dns_name_fromtext(&name, &buffer, origin, options,
 					  target));
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -178,8 +177,7 @@ totext_amtrelay(ARGS_TOTEXT) {
 		return (dns_name_totext(&name, false, target));
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/loc_29.c b/lib/dns/rdata/generic/loc_29.c
index 4c203a4de32..d6632e61494 100644
--- a/lib/dns/rdata/generic/loc_29.c
+++ b/lib/dns/rdata/generic/loc_29.c
@@ -272,8 +272,7 @@ loc_getlatitude(isc_lex_t *lexer, unsigned long *latitude) {
 		*latitude = 0x80000000 - (d1 * 3600 + m1 * 60) * 1000 - s1;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	return (ISC_R_SUCCESS);
@@ -294,8 +293,7 @@ loc_getlongitude(isc_lex_t *lexer, unsigned long *longitude) {
 		*longitude = 0x80000000 - (d2 * 3600 + m2 * 60) * 1000 - s2;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/rdata/in_1/svcb_64.c b/lib/dns/rdata/in_1/svcb_64.c
index b2b8657b970..848505269be 100644
--- a/lib/dns/rdata/in_1/svcb_64.c
+++ b/lib/dns/rdata/in_1/svcb_64.c
@@ -322,8 +322,7 @@ svc_fromtext(isc_textregion_t *region, isc_buffer_t *target) {
 			RETERR(svcsortkeylist(target, used));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		len = isc_buffer_usedlength(target) -
@@ -732,8 +731,7 @@ generic_totext_in_svcb(ARGS_TOTEXT) {
 			}
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c
index 5865b8a4d64..4d910a640e9 100644
--- a/lib/dns/resolver.c
+++ b/lib/dns/resolver.c
@@ -2323,8 +2323,7 @@ addr2buf(void *buf, const size_t bufsize, const isc_sockaddr_t *sockaddr) {
 		memmove(buf, &netaddr.type.in6, 16);
 		return (16);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (0);
 }
@@ -7088,8 +7087,7 @@ is_answertarget_allowed(fetchctx_t *fctx, dns_name_t *qname, dns_name_t *rname,
 		RUNTIME_CHECK(result == ISC_R_SUCCESS);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (chainingp != NULL) {
diff --git a/lib/dns/rpz.c b/lib/dns/rpz.c
index 0f316308dda..d03330dca0c 100644
--- a/lib/dns/rpz.c
+++ b/lib/dns/rpz.c
@@ -280,8 +280,7 @@ dns_rpz_policy2str(dns_rpz_policy_t policy) {
 		str = "DNS64";
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (str);
 }
@@ -345,8 +344,7 @@ make_addr_set(dns_rpz_addr_zbits_t *tgt_set, dns_rpz_zbits_t zbits,
 		tgt_set->nsip = zbits;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -363,8 +361,7 @@ make_nm_set(dns_rpz_nm_zbits_t *tgt_set, dns_rpz_num_t rpz_num,
 		tgt_set->ns = DNS_RPZ_ZBIT(rpz_num);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -619,8 +616,7 @@ adj_trigger_cnt(dns_rpz_zones_t *rpzs, dns_rpz_num_t rpz_num,
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (inc) {
@@ -2658,8 +2654,7 @@ dns_rpz_find_ip(dns_rpz_zones_t *rpzs, dns_rpz_type_t rpz_type,
 		rpz_num = zbit_to_num(found->set.nsip & tgt_set.nsip);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	result = ip2name(&found->ip, found->prefix, dns_rootname, ip_name);
 	RWUNLOCK(&rpzs->search_lock, isc_rwlocktype_read);
diff --git a/lib/dns/rrl.c b/lib/dns/rrl.c
index 142b47fd1d1..9d3c8f6fa34 100644
--- a/lib/dns/rrl.c
+++ b/lib/dns/rrl.c
@@ -482,8 +482,7 @@ get_rate(dns_rrl_t *rrl, dns_rrl_rtype_t rtype) {
 	case DNS_RRL_RTYPE_ALL:
 		return (&rrl->all_per_second);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -852,8 +851,7 @@ make_log_buf(dns_rrl_t *rrl, dns_rrl_entry_t *e, const char *str1,
 		ADD_LOG_CSTR(&lb, "slip ");
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	switch (e->key.s.rtype) {
@@ -881,8 +879,7 @@ make_log_buf(dns_rrl_t *rrl, dns_rrl_entry_t *e, const char *str1,
 		ADD_LOG_CSTR(&lb, "all ");
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (plural) {
diff --git a/lib/dns/sdb.c b/lib/dns/sdb.c
index 54e9b48018b..2608c294c22 100644
--- a/lib/dns/sdb.c
+++ b/lib/dns/sdb.c
@@ -1069,8 +1069,7 @@ expirenode(dns_db_t *db, dns_dbnode_t *node, isc_stdtime_t now) {
 	UNUSED(db);
 	UNUSED(node);
 	UNUSED(now);
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 }
 
 static void
diff --git a/lib/dns/sdlz.c b/lib/dns/sdlz.c
index ba50846794d..9b2af6d0ed9 100644
--- a/lib/dns/sdlz.c
+++ b/lib/dns/sdlz.c
@@ -736,8 +736,7 @@ expirenode(dns_db_t *db, dns_dbnode_t *node, isc_stdtime_t now) {
 	UNUSED(db);
 	UNUSED(node);
 	UNUSED(now);
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 }
 
 static void
diff --git a/lib/dns/ssu.c b/lib/dns/ssu.c
index a254c610f4a..92db924469f 100644
--- a/lib/dns/ssu.c
+++ b/lib/dns/ssu.c
@@ -227,8 +227,7 @@ reverse_from_address(dns_name_t *tcpself, const isc_netaddr_t *tcpaddr) {
 		RUNTIME_CHECK(result < sizeof(buf));
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	isc_buffer_init(&b, buf, strlen(buf));
 	isc_buffer_add(&b, strlen(buf));
@@ -269,8 +268,7 @@ stf_from_address(dns_name_t *stfself, const isc_netaddr_t *tcpaddr) {
 		RUNTIME_CHECK(result < sizeof(buf));
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	isc_buffer_init(&b, buf, strlen(buf));
 	isc_buffer_add(&b, strlen(buf));
diff --git a/lib/dns/tests/dnstest.c b/lib/dns/tests/dnstest.c
index 47ff71644d9..e3da9d47856 100644
--- a/lib/dns/tests/dnstest.c
+++ b/lib/dns/tests/dnstest.c
@@ -372,7 +372,7 @@ fromhex(char c) {
 
 	printf("bad input format: %02x\n", c);
 	exit(3);
-	/* NOTREACHED */
+	UNREACHABLE();
 }
 
 /*
diff --git a/lib/dns/tests/geoip_test.c b/lib/dns/tests/geoip_test.c
index 2523c7b8f0c..abe64f9e4e5 100644
--- a/lib/dns/tests/geoip_test.c
+++ b/lib/dns/tests/geoip_test.c
@@ -120,8 +120,7 @@ entry_exists(dns_geoip_subtype_t subtype, const char *addr) {
 	} else if (inet_pton(AF_INET, addr, &in4) == 1) {
 		isc_netaddr_fromin(&na, &in4);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	db = geoip2_database(&geoip, fix_subtype(&geoip, subtype));
diff --git a/lib/dns/transport.c b/lib/dns/transport.c
index 7937f2d2104..e7fbb70ac3c 100644
--- a/lib/dns/transport.c
+++ b/lib/dns/transport.c
@@ -327,8 +327,7 @@ dns_transport_get_prefer_server_ciphers(const dns_transport_t *transport,
 		return (true);
 	}
 
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 	return false;
 }
 
diff --git a/lib/dns/tsec.c b/lib/dns/tsec.c
index 6127cf34e9b..fcb761348bc 100644
--- a/lib/dns/tsec.c
+++ b/lib/dns/tsec.c
@@ -91,8 +91,7 @@ dns_tsec_create(isc_mem_t *mctx, dns_tsectype_t type, dst_key_t *key,
 		tsec->ukey.key = key;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	tsec->magic = DNS_TSEC_MAGIC;
@@ -118,8 +117,7 @@ dns_tsec_destroy(dns_tsec_t **tsecp) {
 		dst_key_free(&tsec->ukey.key);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	tsec->magic = 0;
@@ -146,7 +144,6 @@ dns_tsec_getkey(dns_tsec_t *tsec, void *keyp) {
 		*(dst_key_t **)keyp = tsec->ukey.key;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
diff --git a/lib/dns/update.c b/lib/dns/update.c
index 610643b8071..9241b1cad65 100644
--- a/lib/dns/update.c
+++ b/lib/dns/update.c
@@ -1970,8 +1970,7 @@ next_state:
 					       state->keyset_kskonly));
 				sigs++;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 			ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
 			ISC_LIST_APPEND(state->work.tuples, t, link);
@@ -2145,8 +2144,7 @@ next_state:
 					       state->keyset_kskonly));
 				sigs++;
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 			ISC_LIST_UNLINK(state->nsec_mindiff.tuples, t, link);
 			ISC_LIST_APPEND(state->work.tuples, t, link);
@@ -2173,8 +2171,7 @@ next_state:
 		INSIST(ISC_LIST_EMPTY(state->nsec_mindiff.tuples));
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 failure:
@@ -2234,8 +2231,7 @@ dns__update_soaserial(uint32_t serial, dns_updatemethod_t method) {
 		}
 		return (serial);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2266,8 +2262,7 @@ dns_update_soaserial(uint32_t serial, dns_updatemethod_t method,
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (used != NULL) {
diff --git a/lib/dns/validator.c b/lib/dns/validator.c
index 5014e500fb1..64f876f807e 100644
--- a/lib/dns/validator.c
+++ b/lib/dns/validator.c
@@ -3085,8 +3085,7 @@ validator_start(isc_task_t *task, isc_event_t *event) {
 
 		result = validate_nx(val, false);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (result != DNS_R_WAIT) {
diff --git a/lib/dns/xfrin.c b/lib/dns/xfrin.c
index 2136cb7fc5e..5df10d3dede 100644
--- a/lib/dns/xfrin.c
+++ b/lib/dns/xfrin.c
@@ -682,8 +682,7 @@ redo:
 		FAIL(DNS_R_EXTRADATA);
 		FALLTHROUGH;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	result = ISC_R_SUCCESS;
 failure:
@@ -1029,8 +1028,7 @@ xfrin_start(dns_xfrin_ctx_t *xfr) {
 				     connect_xfr, 30000, 0, tlsctx);
 	} break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/zone.c b/lib/dns/zone.c
index 58f17334700..646bfd1f5da 100644
--- a/lib/dns/zone.c
+++ b/lib/dns/zone.c
@@ -10135,8 +10135,7 @@ normalize_key(dns_rdata_t *rr, dns_rdata_t *target, unsigned char *data,
 				     &dnskey, &buf);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (ISC_R_SUCCESS);
 }
@@ -18176,8 +18175,7 @@ got_transfer_quota(isc_task_t *task, isc_event_t *event) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	UNLOCK_ZONE(zone);
 	INSIST(isc_sockaddr_pf(&primaryaddr) == isc_sockaddr_pf(&sourceaddr));
@@ -19952,8 +19950,7 @@ dns_zone_setdialup(dns_zone_t *zone, dns_dialuptype_t dialup) {
 		DNS_ZONE_SETFLAG(zone, DNS_ZONEFLG_NOREFRESH);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	UNLOCK_ZONE(zone);
 }
@@ -20035,8 +20032,7 @@ dns_zonemgr_getcount(dns_zonemgr_t *zmgr, int state) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	RWUNLOCK(&zmgr->rwlock, isc_rwlocktype_read);
diff --git a/lib/isc/app.c b/lib/isc/app.c
index d5bf097e99b..d02371c9500 100644
--- a/lib/isc/app.c
+++ b/lib/isc/app.c
@@ -245,8 +245,7 @@ isc_app_ctxrun(isc_appctx_t *ctx) {
 							     true);
 					break;
 				default:
-					INSIST(0);
-					ISC_UNREACHABLE();
+					UNREACHABLE();
 				}
 			}
 		} else {
diff --git a/lib/isc/assertions.c b/lib/isc/assertions.c
index 5470d81715a..8b954cf475e 100644
--- a/lib/isc/assertions.c
+++ b/lib/isc/assertions.c
@@ -48,7 +48,6 @@ isc_assertion_failed(const char *file, int line, isc_assertiontype_t type,
 		     const char *cond) {
 	isc_assertion_failed_cb(file, line, type, cond);
 	abort();
-	/* NOTREACHED */
 }
 
 /*% Set callback. */
diff --git a/lib/isc/include/isc/assertions.h b/lib/isc/include/isc/assertions.h
index 7045179cbaf..d5dbced8534 100644
--- a/lib/isc/include/isc/assertions.h
+++ b/lib/isc/include/isc/assertions.h
@@ -66,4 +66,9 @@ isc_assertion_typetotext(isc_assertiontype_t type);
 					isc_assertiontype_invariant, #cond), \
 		 0)))
 
+#define ISC_UNREACHABLE()                                                   \
+	(isc_assertion_failed(__FILE__, __LINE__, isc_assertiontype_insist, \
+			      "unreachable"),                               \
+	 __builtin_unreachable())
+
 ISC_LANG_ENDDECLS
diff --git a/lib/isc/include/isc/util.h b/lib/isc/include/isc/util.h
index d0cd0197d38..63d3af340c4 100644
--- a/lib/isc/include/isc/util.h
+++ b/lib/isc/include/isc/util.h
@@ -218,12 +218,6 @@
  * Performance
  */
 
-#ifdef HAVE_BUILTIN_UNREACHABLE
-#define ISC_UNREACHABLE() __builtin_unreachable();
-#else /* ifdef HAVE_BUILTIN_UNREACHABLE */
-#define ISC_UNREACHABLE()
-#endif /* ifdef HAVE_BUILTIN_UNREACHABLE */
-
 /* GCC defines __SANITIZE_ADDRESS__, so reuse the macro for clang */
 #if __has_feature(address_sanitizer)
 #define __SANITIZE_ADDRESS__ 1
@@ -278,6 +272,8 @@ mock_assert(const int result, const char *const expression,
 	((!(expression))                                                      \
 		 ? (mock_assert(0, #expression, __FILE__, __LINE__), abort()) \
 		 : (void)0)
+#define UNREACHABLE() \
+	(mock_assert(0, "unreachable", __FILE__, __LINE__), abort())
 #define _assert_true(c, e, f, l) \
 	((c) ? (void)0 : (_assert_true(0, e, f, l), abort()))
 #define _assert_int_equal(a, b, f, l) \
@@ -300,6 +296,8 @@ mock_assert(const int result, const char *const expression,
 /*% Invariant Assertion */
 #define INVARIANT(e) ISC_INVARIANT(e)
 
+#define UNREACHABLE() ISC_UNREACHABLE()
+
 #endif /* UNIT_TESTING */
 
 /*
diff --git a/lib/isc/interfaceiter.c b/lib/isc/interfaceiter.c
index 54b13eba65b..abb16f4b6da 100644
--- a/lib/isc/interfaceiter.c
+++ b/lib/isc/interfaceiter.c
@@ -125,8 +125,7 @@ get_addr(unsigned int family, isc_netaddr_t *dst, struct sockaddr *src,
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isc/log.c b/lib/isc/log.c
index f41c39237dd..95c3e6b05d6 100644
--- a/lib/isc/log.c
+++ b/lib/isc/log.c
@@ -707,8 +707,7 @@ isc_log_createchannel(isc_logconfig_t *lcfg, const char *name,
 		break;
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	ISC_LIST_PREPEND(lcfg->channels, channel, link);
diff --git a/lib/isc/mem.c b/lib/isc/mem.c
index f21954b65af..ea6d4cc95e5 100644
--- a/lib/isc/mem.c
+++ b/lib/isc/mem.c
@@ -319,8 +319,7 @@ delete_trace_entry(isc_mem_t *mctx, const void *ptr, size_t size,
 	 * If we get here, we didn't find the item on the list.  We're
 	 * screwed.
 	 */
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 unlock:
 	MCTXUNLOCK(mctx);
 }
@@ -1436,8 +1435,7 @@ isc__mem_checkdestroyed(void) {
 			print_contexts(file);
 		}
 #endif /* if ISC_MEM_TRACKLINES */
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	UNLOCK(&contextslock);
 }
diff --git a/lib/isc/net.c b/lib/isc/net.c
index 9a720837607..5525762d93a 100644
--- a/lib/isc/net.c
+++ b/lib/isc/net.c
@@ -506,8 +506,7 @@ cmsgsend(int s, int level, int type, struct addrinfo *res) {
 		break;
 #endif /* ifdef IPV6_TCLASS */
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (sendmsg(s, &msg, 0) < 0) {
diff --git a/lib/isc/netaddr.c b/lib/isc/netaddr.c
index 9ccf12e74b6..940fbf0370c 100644
--- a/lib/isc/netaddr.c
+++ b/lib/isc/netaddr.c
@@ -352,8 +352,7 @@ isc_netaddr_fromsockaddr(isc_netaddr_t *t, const isc_sockaddr_t *s) {
 		t->zone = 0;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isc/netmgr/http.c b/lib/isc/netmgr/http.c
index 0d06c1b9020..d09ad5b8c7a 100644
--- a/lib/isc/netmgr/http.c
+++ b/lib/isc/netmgr/http.c
@@ -2107,8 +2107,7 @@ server_on_request_recv(nghttp2_session *ngsession,
 		INSIST(socket->h2.content_length > 0);
 		isc_buffer_usedregion(&socket->h2.rbuf, &data);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	server_call_cb(socket, session, ISC_R_SUCCESS, &data);
@@ -2671,8 +2670,7 @@ isc__nm_http_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!isc__nm_in_netthread()) {
diff --git a/lib/isc/netmgr/netmgr.c b/lib/isc/netmgr/netmgr.c
index 4216b5c24b1..122e5e84a20 100644
--- a/lib/isc/netmgr/netmgr.c
+++ b/lib/isc/netmgr/netmgr.c
@@ -521,8 +521,7 @@ isc__netmgr_destroy(isc_nm_t **netmgrp) {
 #ifdef NETMGR_TRACE
 	if (isc_refcount_current(&mgr->references) > 1) {
 		isc__nm_dump_active(mgr);
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 #endif
 
@@ -720,8 +719,7 @@ process_all_queues(isc__networker_t *worker) {
 			reschedule = true;
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -793,8 +791,7 @@ isc__nm_async_task(isc__networker_t *worker, isc__netievent_t *ev0) {
 	case ISC_R_SUCCESS:
 		return;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -922,8 +919,7 @@ process_netievent(isc__networker_t *worker, isc__netievent_t *ievent) {
 		NETIEVENT_CASE(resume);
 		NETIEVENT_CASE_NOMORE(pause);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (true);
 }
@@ -1074,8 +1070,7 @@ isc__nm_enqueue_ievent(isc__networker_t *worker, isc__netievent_t *event) {
 	} else {
 		switch (event->type) {
 		case netievent_prio:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 			break;
 		case netievent_privilegedtask:
 			type = NETIEVENT_PRIVILEGED;
@@ -1462,8 +1457,7 @@ isc___nmsocket_init(isc_nmsocket_t *sock, isc_nm_t *mgr, isc_nmsocket_type type,
 			 */
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		break;
 	case isc_nm_tcpsocket:
@@ -1482,8 +1476,7 @@ isc___nmsocket_init(isc_nmsocket_t *sock, isc_nm_t *mgr, isc_nmsocket_type type,
 			sock->statsindex = tcp6statsindex;
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		break;
 	default:
@@ -1921,8 +1914,7 @@ isc__nm_failed_read_cb(isc_nmsocket_t *sock, isc_result_t result, bool async) {
 		isc__nm_tlsdns_failed_read_cb(sock, result, async);
 		return;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2142,8 +2134,7 @@ isc__nm_alloc_cb(uv_handle_t *handle, size_t size, uv_buf_t *buf) {
 		buf->len = ISC_NETMGR_TCP_RECVBUF_SIZE;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	REQUIRE(buf->len <= ISC_NETMGR_RECVBUF_SIZE);
@@ -2182,8 +2173,7 @@ isc__nm_start_reading(isc_nmsocket_t *sock) {
 		UV_RUNTIME_CHECK(uv_read_start, r);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	atomic_store(&sock->reading, true);
 }
@@ -2208,8 +2198,7 @@ isc__nm_stop_reading(isc_nmsocket_t *sock) {
 		UV_RUNTIME_CHECK(uv_read_stop, r);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	atomic_store(&sock->reading, false);
 }
@@ -2234,8 +2223,7 @@ processbuffer(isc_nmsocket_t *sock) {
 	case isc_nm_tlsdnssocket:
 		return (isc__nm_tlsdns_processbuffer(sock));
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2514,8 +2502,7 @@ isc_nm_send(isc_nmhandle_t *handle, isc_region_t *region, isc_nm_cb_t cb,
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2545,8 +2532,7 @@ isc_nm_read(isc_nmhandle_t *handle, isc_nm_recv_cb_t cb, void *cbarg) {
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2573,8 +2559,7 @@ isc_nm_cancelread(isc_nmhandle_t *handle) {
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2594,8 +2579,7 @@ isc_nm_pauseread(isc_nmhandle_t *handle) {
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2615,8 +2599,7 @@ isc_nm_resumeread(isc_nmhandle_t *handle) {
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2646,8 +2629,7 @@ isc_nm_stoplistening(isc_nmsocket_t *sock) {
 		break;
 #endif
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -2828,7 +2810,7 @@ isc__nmsocket_reset(isc_nmsocket_t *sock) {
 		break;
 	default:
 		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 		break;
 	}
 
@@ -2870,8 +2852,7 @@ isc__nmsocket_shutdown(isc_nmsocket_t *sock) {
 	case isc_nm_tlsdnslistener:
 		return;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -3348,8 +3329,7 @@ isc__nm_set_network_buffers(isc_nm_t *nm, uv_handle_t *handle) {
 			atomic_load_relaxed(&nm->send_udp_buffer_size);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (recv_buffer_size > 0) {
@@ -3457,8 +3437,7 @@ isc_nm_bad_request(isc_nmhandle_t *handle) {
 	case isc_nm_tlssocket:
 #endif /* HAVE_LIBNGHTTP2 */
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 		break;
 	}
 }
@@ -3481,8 +3460,7 @@ isc_nm_xfr_allowed(isc_nmhandle_t *handle) {
 		return (false);
 	}
 
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 
 	return (false);
 }
@@ -3526,7 +3504,7 @@ isc_nm_set_maxage(isc_nmhandle_t *handle, const uint32_t ttl) {
 #endif /* HAVE_LIBNGHTTP2 */
 	default:
 		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 		break;
 	}
 }
@@ -3602,8 +3580,7 @@ nmsocket_type_totext(isc_nmsocket_type type) {
 	case isc_nm_httpsocket:
 		return ("isc_nm_httpsocket");
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isc/netmgr/tcp.c b/lib/isc/netmgr/tcp.c
index 85edea5df6b..9fc80c4d20f 100644
--- a/lib/isc/netmgr/tcp.c
+++ b/lib/isc/netmgr/tcp.c
@@ -647,8 +647,7 @@ isc__nm_tcp_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!isc__nm_in_netthread()) {
@@ -1158,8 +1157,7 @@ tcp_stop_cb(uv_handle_t *handle) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
@@ -1177,8 +1175,7 @@ tcp_close_sock(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index a0d7961ff80..53c2f30ff2b 100644
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -613,8 +613,7 @@ isc__nm_tcpdns_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!isc__nm_in_netthread()) {
@@ -1210,8 +1209,7 @@ tcpdns_stop_cb(uv_handle_t *handle) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
@@ -1229,8 +1227,7 @@ tcpdns_close_sock(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
diff --git a/lib/isc/netmgr/tlsdns.c b/lib/isc/netmgr/tlsdns.c
index 1347666232d..4864fcc477b 100644
--- a/lib/isc/netmgr/tlsdns.c
+++ b/lib/isc/netmgr/tlsdns.c
@@ -685,8 +685,7 @@ isc__nm_tlsdns_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!isc__nm_in_netthread()) {
@@ -760,8 +759,7 @@ isc__nm_async_tlsdnsshutdown(isc__networker_t *worker, isc__netievent_t *ev0) {
 		tls_shutdown(sock);
 		return;
 	case 0:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	case SSL_ERROR_ZERO_RETURN:
 		tls_error(sock, ISC_R_EOF);
 		break;
@@ -1737,8 +1735,7 @@ tlsdns_send_direct(isc_nmsocket_t *sock, isc__nm_uvreq_t *req) {
 	case SSL_ERROR_WANT_READ:
 		break;
 	case 0:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	default:
 		return (ISC_R_TLSERROR);
 	}
@@ -1764,8 +1761,7 @@ tlsdns_stop_cb(uv_handle_t *handle) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
@@ -1788,8 +1784,7 @@ tlsdns_close_sock(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
diff --git a/lib/isc/netmgr/tlsstream.c b/lib/isc/netmgr/tlsstream.c
index 6df651f2048..252b52da9f5 100644
--- a/lib/isc/netmgr/tlsstream.c
+++ b/lib/isc/netmgr/tlsstream.c
@@ -856,8 +856,7 @@ isc__nm_tls_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	atomic_store(&sock->listening, false);
diff --git a/lib/isc/netmgr/udp.c b/lib/isc/netmgr/udp.c
index 1067f015331..3a43cd3b84d 100644
--- a/lib/isc/netmgr/udp.c
+++ b/lib/isc/netmgr/udp.c
@@ -516,8 +516,7 @@ isc__nm_udp_stoplistening(isc_nmsocket_t *sock) {
 
 	if (!atomic_compare_exchange_strong(&sock->closing, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	if (!isc__nm_in_netthread()) {
@@ -1175,8 +1174,7 @@ udp_stop_cb(uv_handle_t *handle) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
@@ -1197,8 +1195,7 @@ udp_close_cb(uv_handle_t *handle) {
 
 	if (!atomic_compare_exchange_strong(&sock->closed, &(bool){ false },
 					    true)) {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	isc__nm_incstats(sock, STATID_CLOSE);
diff --git a/lib/isc/rwlock.c b/lib/isc/rwlock.c
index 4c11feb5181..c76ea74dda3 100644
--- a/lib/isc/rwlock.c
+++ b/lib/isc/rwlock.c
@@ -62,8 +62,7 @@ isc_rwlock_lock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	return (ISC_R_SUCCESS);
 }
@@ -94,8 +93,7 @@ isc_rwlock_trylock(isc_rwlock_t *rwl, isc_rwlocktype_t type) {
 	case EAGAIN:
 		return (ISC_R_LOCKBUSY);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isc/siphash.c b/lib/isc/siphash.c
index 0f83ef5f2e6..1a863ff8e1d 100644
--- a/lib/isc/siphash.c
+++ b/lib/isc/siphash.c
@@ -142,8 +142,7 @@ isc_siphash24(const uint8_t *k, const uint8_t *in, const size_t inlen,
 	case 0:
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	v3 ^= b;
@@ -208,8 +207,7 @@ isc_halfsiphash24(const uint8_t *k, const uint8_t *in, const size_t inlen,
 	case 0:
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	v3 ^= b;
diff --git a/lib/isc/sockaddr.c b/lib/isc/sockaddr.c
index e2f363ef1bc..85b3d284394 100644
--- a/lib/isc/sockaddr.c
+++ b/lib/isc/sockaddr.c
@@ -295,8 +295,7 @@ isc_sockaddr_anyofpf(isc_sockaddr_t *sockaddr, int pf) {
 		isc_sockaddr_any6(sockaddr);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -366,8 +365,7 @@ isc_sockaddr_fromnetaddr(isc_sockaddr_t *sockaddr, const isc_netaddr_t *na,
 		sockaddr->type.sin6.sin6_port = htons(port);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	ISC_LINK_INIT(sockaddr, link);
 }
diff --git a/lib/isc/timer.c b/lib/isc/timer.c
index 720f972260b..f833000601f 100644
--- a/lib/isc/timer.c
+++ b/lib/isc/timer.c
@@ -118,7 +118,7 @@ schedule(isc_timer_t *timer, isc_time_t *now, bool signal_ok) {
 		break;
 	default:
 		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
@@ -426,7 +426,7 @@ dispatch(isc_timermgr_t *manager, isc_time_t *now) {
 			break;
 		default:
 			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		timer->index = 0;
diff --git a/lib/isc/tls.c b/lib/isc/tls.c
index a726d94aeb3..b71cdd6aade 100644
--- a/lib/isc/tls.c
+++ b/lib/isc/tls.c
@@ -511,8 +511,7 @@ get_tls_version_disable_bit(const isc_tls_protocol_version_t tls_ver) {
 #endif
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 		break;
 	};
 
diff --git a/lib/isc/url.c b/lib/isc/url.c
index 8758496e5b0..7f618743410 100644
--- a/lib/isc/url.c
+++ b/lib/isc/url.c
@@ -596,8 +596,7 @@ isc_url_parse(const char *buf, size_t buflen, bool is_connect,
 			break;
 
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		/* Nothing's changed; soldier on */
diff --git a/lib/isccc/sexpr.c b/lib/isccc/sexpr.c
index c703710c46e..62c80c46ed4 100644
--- a/lib/isccc/sexpr.c
+++ b/lib/isccc/sexpr.c
@@ -211,8 +211,7 @@ isccc_sexpr_print(isccc_sexpr_t *sexpr, FILE *stream) {
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isccfg/aclconf.c b/lib/isccfg/aclconf.c
index d03dc40fe32..716ffe6cee0 100644
--- a/lib/isccfg/aclconf.c
+++ b/lib/isccfg/aclconf.c
@@ -399,8 +399,7 @@ get_subtype(const cfg_obj_t *obj, isc_log_t *lctx, dns_geoip_subtype_t subtype,
 		}
 		return (subtype);
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/isccfg/namedconf.c b/lib/isccfg/namedconf.c
index 36e20cd1b28..203e066926c 100644
--- a/lib/isccfg/namedconf.c
+++ b/lib/isccfg/namedconf.c
@@ -3172,8 +3172,7 @@ parse_querysource(cfg_parser_t *pctx, const cfg_type_t *type, cfg_obj_t **ret) {
 	} else if ((*flagp & CFG_ADDR_V6OK) != 0) {
 		isc_netaddr_any6(&netaddr);
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	for (;;) {
@@ -3258,8 +3257,7 @@ doc_querysource(cfg_printer_t *pctx, const cfg_type_t *type) {
 	} else if ((*flagp & CFG_ADDR_V6OK) != 0) {
 		cfg_print_cstr(pctx, "<ipv6_address>");
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	cfg_print_cstr(pctx, " | * ) [ port ( <integer> | * ) ] ) | "
 			     "( [ [ address ] ( ");
@@ -3268,8 +3266,7 @@ doc_querysource(cfg_printer_t *pctx, const cfg_type_t *type) {
 	} else if ((*flagp & CFG_ADDR_V6OK) != 0) {
 		cfg_print_cstr(pctx, "<ipv6_address>");
 	} else {
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	cfg_print_cstr(pctx, " | * ) ] port ( <integer> | * ) ) )"
 			     " [ dscp <integer> ]");
@@ -3893,8 +3890,7 @@ cfg_print_zonegrammar(const unsigned int zonetype, unsigned int flags,
 		/* no zone type is specified for these */
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	for (clause = clauses; clause->name != NULL; clause++) {
diff --git a/lib/isccfg/parser.c b/lib/isccfg/parser.c
index 1b4e164725a..eeea6e77904 100644
--- a/lib/isccfg/parser.c
+++ b/lib/isccfg/parser.c
@@ -423,8 +423,7 @@ cfg_tuple_get(const cfg_obj_t *tupleobj, const char *name) {
 			return (tupleobj->value.tuple[i]);
 		}
 	}
-	INSIST(0);
-	ISC_UNREACHABLE();
+	UNREACHABLE();
 }
 
 isc_result_t
@@ -2679,8 +2678,7 @@ cfg_print_mapbody(cfg_printer_t *pctx, const cfg_obj_t *obj) {
 			} else if (result == ISC_R_NOTFOUND) {
 				/* do nothing */
 			} else {
-				INSIST(0);
-				ISC_UNREACHABLE();
+				UNREACHABLE();
 			}
 		}
 	}
@@ -3015,8 +3013,7 @@ token_addr(cfg_parser_t *pctx, unsigned int flags, isc_netaddr_t *na) {
 			isc_netaddr_any6(na);
 			return (ISC_R_SUCCESS);
 		} else {
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		if ((flags & (CFG_ADDR_V4OK | CFG_ADDR_V4PREFIXOK)) != 0) {
@@ -3294,8 +3291,7 @@ cfg_parse_netprefix(cfg_parser_t *pctx, const cfg_type_t *type,
 		addrlen = 128;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 	expectprefix = (result == ISC_R_IPV4PREFIX);
 	CHECK(cfg_peektoken(pctx, 0));
diff --git a/lib/ns/client.c b/lib/ns/client.c
index b0fa0c40e99..27fdffb15fb 100644
--- a/lib/ns/client.c
+++ b/lib/ns/client.c
@@ -678,8 +678,7 @@ renderend:
 					    ISC_MIN((int)respsize / 16, 256));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 #ifdef HAVE_DNSTAP
@@ -708,8 +707,7 @@ renderend:
 					    ISC_MIN((int)respsize / 16, 256));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
@@ -1072,8 +1070,7 @@ no_nsid:
 			memmove(addr, &client->ecs.addr.type, addrl);
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		isc_buffer_init(&buf, ecs, sizeof(ecs));
@@ -1193,8 +1190,7 @@ compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
 			inputlen = 32;
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		isc_siphash24(secret, input, inputlen, digest);
@@ -1235,8 +1231,7 @@ compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
 					 digest);
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 		for (i = 0; i < 8; i++) {
 			digest[i] ^= digest[i + 8];
@@ -1246,8 +1241,7 @@ compute_cookie(ns_client_t *client, uint32_t when, uint32_t nonce,
 	}
 
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
@@ -1871,8 +1865,7 @@ ns__client_request(isc_nmhandle_t *handle, isc_result_t eresult,
 					    ISC_MIN((int)reqsize / 16, 18));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	} else {
 		switch (isc_sockaddr_pf(&client->peeraddr)) {
@@ -1885,8 +1878,7 @@ ns__client_request(isc_nmhandle_t *handle, isc_result_t eresult,
 					    ISC_MIN((int)reqsize / 16, 18));
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 	}
 
diff --git a/lib/ns/query.c b/lib/ns/query.c
index 9a661c6d0a2..253baa42d5d 100644
--- a/lib/ns/query.c
+++ b/lib/ns/query.c
@@ -2731,8 +2731,7 @@ rpz_get_zbits(ns_client_t *client, dns_rdatatype_t ip_type,
 		}
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
@@ -2969,8 +2968,7 @@ rpz_get_p_name(ns_client_t *client, dns_name_t *p_name, dns_rpz_zone_t *rpz,
 		suffix = &rpz->nsip;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
@@ -3404,8 +3402,7 @@ dnsrps_rewrite_ip(ns_client_t *client, const isc_netaddr_t *netaddr,
 		recursed = true;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	do {
@@ -3455,8 +3452,7 @@ dnsrps_rewrite_name(ns_client_t *client, dns_name_t *trig_name, bool recursed,
 		trig = LIBRPZ_TRIG_NSDNAME;
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	dns_name_toregion(trig_name, &r);
@@ -7306,8 +7302,7 @@ query_checkrpz(query_ctx_t *qctx, isc_result_t result) {
 			qctx->want_restart = true;
 			return (ISC_R_COMPLETE);
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		/*
@@ -9202,8 +9197,7 @@ query_nodata(query_ctx_t *qctx, isc_result_t res) {
 				dns64_ttl(qctx->db, qctx->version);
 			break;
 		default:
-			INSIST(0);
-			ISC_UNREACHABLE();
+			UNREACHABLE();
 		}
 
 		SAVE(qctx->client->query.dns64_aaaa, qctx->rdataset);
@@ -11602,8 +11596,7 @@ query_setup_sortlist(query_ctx_t *qctx) {
 	case NS_SORTLISTTYPE_NONE:
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 }
 
diff --git a/lib/ns/tests/nstest.c b/lib/ns/tests/nstest.c
index 690af2c64be..8158a15aee7 100644
--- a/lib/ns/tests/nstest.c
+++ b/lib/ns/tests/nstest.c
@@ -919,7 +919,7 @@ fromhex(char c) {
 
 	printf("bad input format: %02x\n", c);
 	exit(3);
-	/* NOTREACHED */
+	UNREACHABLE();
 }
 
 isc_result_t
diff --git a/lib/ns/tests/query_test.c b/lib/ns/tests/query_test.c
index e1b05c61c10..9c8005fa5f9 100644
--- a/lib/ns/tests/query_test.c
+++ b/lib/ns/tests/query_test.c
@@ -433,8 +433,7 @@ run_start_test(const ns__query_start_test_params_t *test) {
 			 test->id.description, test->id.lineno);
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	/*
diff --git a/lib/ns/xfrout.c b/lib/ns/xfrout.c
index c763db873ed..04388d522cc 100644
--- a/lib/ns/xfrout.c
+++ b/lib/ns/xfrout.c
@@ -758,8 +758,7 @@ ns_xfr_start(ns_client_t *client, dns_rdatatype_t reqtype) {
 		mnemonic = "IXFR";
 		break;
 	default:
-		INSIST(0);
-		ISC_UNREACHABLE();
+		UNREACHABLE();
 	}
 
 	ns_client_log(client, DNS_LOGCATEGORY_XFER_OUT, NS_LOGMODULE_XFER_OUT,