diff --git a/lib/dns/include/dns/rdata.h b/lib/dns/include/dns/rdata.h
index aa0b48013c..a6e22e7e59 100644
--- a/lib/dns/include/dns/rdata.h
+++ b/lib/dns/include/dns/rdata.h
@@ -523,7 +523,8 @@ dns_rdata_tostruct(const dns_rdata_t *rdata, void *target, isc_mem_t *mctx);
  *
  * Result:
  *\li	Success
- *\li	Resource Limit: Not enough memory
+ *\li	Not Implemented
+ *\li	Unexpected end of input
  */
 
 void
diff --git a/lib/dns/rdata.c b/lib/dns/rdata.c
index e1adee9dd8..919c312ac6 100644
--- a/lib/dns/rdata.c
+++ b/lib/dns/rdata.c
@@ -420,11 +420,14 @@ name_duporclone(const dns_name_t *source, isc_mem_t *mctx, dns_name_t *target) {
 
 static inline void *
 mem_maybedup(isc_mem_t *mctx, void *source, size_t length) {
-	void *copy;
+	void *copy = NULL;
+
+	REQUIRE(source != NULL);
 
 	if (mctx == NULL) {
 		return (source);
 	}
+
 	copy = isc_mem_allocate(mctx, length);
 	memmove(copy, source, length);
 
diff --git a/lib/dns/rdata/any_255/tsig_250.c b/lib/dns/rdata/any_255/tsig_250.c
index f84d8b7926..d6bf328798 100644
--- a/lib/dns/rdata/any_255/tsig_250.c
+++ b/lib/dns/rdata/any_255/tsig_250.c
@@ -496,9 +496,6 @@ tostruct_any_tsig(ARGS_TOSTRUCT) {
 	 */
 	INSIST(sr.length >= tsig->siglen);
 	tsig->signature = mem_maybedup(mctx, sr.base, tsig->siglen);
-	if (tsig->signature == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&sr, tsig->siglen);
 
 	/*
@@ -524,21 +521,9 @@ tostruct_any_tsig(ARGS_TOSTRUCT) {
 	 */
 	INSIST(sr.length == tsig->otherlen);
 	tsig->other = mem_maybedup(mctx, sr.base, tsig->otherlen);
-	if (tsig->other == NULL) {
-		goto cleanup;
-	}
 
 	tsig->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&tsig->algorithm, tsig->mctx);
-	}
-	if (mctx != NULL && tsig->signature != NULL) {
-		isc_mem_free(mctx, tsig->signature);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/amtrelay_260.c b/lib/dns/rdata/generic/amtrelay_260.c
index dfe4685a51..020cfcf06d 100644
--- a/lib/dns/rdata/generic/amtrelay_260.c
+++ b/lib/dns/rdata/generic/amtrelay_260.c
@@ -360,9 +360,6 @@ tostruct_amtrelay(ARGS_TOSTRUCT) {
 		if (region.length != 0) {
 			amtrelay->data = mem_maybedup(mctx, region.base,
 						      region.length);
-			if (amtrelay->data == NULL) {
-				return (ISC_R_NOMEMORY);
-			}
 		}
 		amtrelay->length = region.length;
 	}
diff --git a/lib/dns/rdata/generic/caa_257.c b/lib/dns/rdata/generic/caa_257.c
index 62adef4a79..eac735fc6b 100644
--- a/lib/dns/rdata/generic/caa_257.c
+++ b/lib/dns/rdata/generic/caa_257.c
@@ -529,9 +529,6 @@ tostruct_caa(ARGS_TOSTRUCT) {
 		return (ISC_R_UNEXPECTEDEND);
 	}
 	caa->tag = mem_maybedup(mctx, sr.base, caa->tag_len);
-	if (caa->tag == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&sr, caa->tag_len);
 
 	/*
@@ -539,9 +536,6 @@ tostruct_caa(ARGS_TOSTRUCT) {
 	 */
 	caa->value_len = sr.length;
 	caa->value = mem_maybedup(mctx, sr.base, sr.length);
-	if (caa->value == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 
 	caa->mctx = mctx;
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/rdata/generic/cert_37.c b/lib/dns/rdata/generic/cert_37.c
index 372060e21b..4ce0fad93e 100644
--- a/lib/dns/rdata/generic/cert_37.c
+++ b/lib/dns/rdata/generic/cert_37.c
@@ -207,10 +207,6 @@ tostruct_cert(ARGS_TOSTRUCT) {
 	cert->length = region.length;
 
 	cert->certificate = mem_maybedup(mctx, region.base, region.length);
-	if (cert->certificate == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	cert->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/csync_62.c b/lib/dns/rdata/generic/csync_62.c
index 32ea3142fc..9cea44881c 100644
--- a/lib/dns/rdata/generic/csync_62.c
+++ b/lib/dns/rdata/generic/csync_62.c
@@ -183,15 +183,8 @@ tostruct_csync(ARGS_TOSTRUCT) {
 
 	csync->len = region.length;
 	csync->typebits = mem_maybedup(mctx, region.base, region.length);
-	if (csync->typebits == NULL) {
-		goto cleanup;
-	}
-
 	csync->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/doa_259.c b/lib/dns/rdata/generic/doa_259.c
index 2a070221b5..d7c6129dd8 100644
--- a/lib/dns/rdata/generic/doa_259.c
+++ b/lib/dns/rdata/generic/doa_259.c
@@ -258,9 +258,6 @@ tostruct_doa(ARGS_TOSTRUCT) {
 	isc_region_consume(&region, 1);
 	INSIST(doa->mediatype_len <= region.length);
 	doa->mediatype = mem_maybedup(mctx, region.base, doa->mediatype_len);
-	if (doa->mediatype == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&region, doa->mediatype_len);
 
 	/*
@@ -270,21 +267,12 @@ tostruct_doa(ARGS_TOSTRUCT) {
 	doa->data = NULL;
 	if (doa->data_len > 0) {
 		doa->data = mem_maybedup(mctx, region.base, doa->data_len);
-		if (doa->data == NULL) {
-			goto cleanup;
-		}
 		isc_region_consume(&region, doa->data_len);
 	}
 
 	doa->mctx = mctx;
 
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL && doa->mediatype != NULL) {
-		isc_mem_free(mctx, doa->mediatype);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/ds_43.c b/lib/dns/rdata/generic/ds_43.c
index 4db39bcee8..6623711ceb 100644
--- a/lib/dns/rdata/generic/ds_43.c
+++ b/lib/dns/rdata/generic/ds_43.c
@@ -293,10 +293,6 @@ generic_tostruct_ds(ARGS_TOSTRUCT) {
 	ds->length = region.length;
 
 	ds->digest = mem_maybedup(mctx, region.base, region.length);
-	if (ds->digest == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	ds->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/gpos_27.c b/lib/dns/rdata/generic/gpos_27.c
index ab9fc9200f..96cdd501e4 100644
--- a/lib/dns/rdata/generic/gpos_27.c
+++ b/lib/dns/rdata/generic/gpos_27.c
@@ -140,43 +140,23 @@ tostruct_gpos(ARGS_TOSTRUCT) {
 	gpos->long_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	gpos->longitude = mem_maybedup(mctx, region.base, gpos->long_len);
-	if (gpos->longitude == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&region, gpos->long_len);
 
 	gpos->lat_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	gpos->latitude = mem_maybedup(mctx, region.base, gpos->lat_len);
-	if (gpos->latitude == NULL) {
-		goto cleanup_longitude;
-	}
 	isc_region_consume(&region, gpos->lat_len);
 
 	gpos->alt_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	if (gpos->lat_len > 0) {
 		gpos->altitude = mem_maybedup(mctx, region.base, gpos->alt_len);
-		if (gpos->altitude == NULL) {
-			goto cleanup_latitude;
-		}
 	} else {
 		gpos->altitude = NULL;
 	}
 
 	gpos->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup_latitude:
-	if (mctx != NULL && gpos->longitude != NULL) {
-		isc_mem_free(mctx, gpos->longitude);
-	}
-
-cleanup_longitude:
-	if (mctx != NULL && gpos->latitude != NULL) {
-		isc_mem_free(mctx, gpos->latitude);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/hinfo_13.c b/lib/dns/rdata/generic/hinfo_13.c
index 2616ee27dc..088bc688a7 100644
--- a/lib/dns/rdata/generic/hinfo_13.c
+++ b/lib/dns/rdata/generic/hinfo_13.c
@@ -125,26 +125,13 @@ tostruct_hinfo(ARGS_TOSTRUCT) {
 	hinfo->cpu_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	hinfo->cpu = mem_maybedup(mctx, region.base, hinfo->cpu_len);
-	if (hinfo->cpu == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&region, hinfo->cpu_len);
 
 	hinfo->os_len = uint8_fromregion(&region);
 	isc_region_consume(&region, 1);
 	hinfo->os = mem_maybedup(mctx, region.base, hinfo->os_len);
-	if (hinfo->os == NULL) {
-		goto cleanup;
-	}
-
 	hinfo->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL && hinfo->cpu != NULL) {
-		isc_mem_free(mctx, hinfo->cpu);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/hip_55.c b/lib/dns/rdata/generic/hip_55.c
index 334e4679a1..314bf1881a 100644
--- a/lib/dns/rdata/generic/hip_55.c
+++ b/lib/dns/rdata/generic/hip_55.c
@@ -322,42 +322,21 @@ tostruct_hip(ARGS_TOSTRUCT) {
 	hip->hit = hip->key = hip->servers = NULL;
 
 	hip->hit = mem_maybedup(mctx, region.base, hip->hit_len);
-	if (hip->hit == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&region, hip->hit_len);
 
 	INSIST(hip->key_len <= region.length);
 
 	hip->key = mem_maybedup(mctx, region.base, hip->key_len);
-	if (hip->key == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&region, hip->key_len);
 
 	hip->servers_len = region.length;
 	if (hip->servers_len != 0) {
 		hip->servers = mem_maybedup(mctx, region.base, region.length);
-		if (hip->servers == NULL) {
-			goto cleanup;
-		}
 	}
 
 	hip->offset = hip->servers_len;
 	hip->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (hip->hit != NULL) {
-		isc_mem_free(mctx, hip->hit);
-	}
-	if (hip->key != NULL) {
-		isc_mem_free(mctx, hip->key);
-	}
-	if (hip->servers != NULL) {
-		isc_mem_free(mctx, hip->servers);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/ipseckey_45.c b/lib/dns/rdata/generic/ipseckey_45.c
index 272a38a4f1..2813818086 100644
--- a/lib/dns/rdata/generic/ipseckey_45.c
+++ b/lib/dns/rdata/generic/ipseckey_45.c
@@ -400,13 +400,6 @@ tostruct_ipseckey(ARGS_TOSTRUCT) {
 	if (ipseckey->keylength != 0U) {
 		ipseckey->key = mem_maybedup(mctx, region.base,
 					     ipseckey->keylength);
-		if (ipseckey->key == NULL) {
-			if (ipseckey->gateway_type == 3) {
-				dns_name_free(&ipseckey->gateway,
-					      ipseckey->mctx);
-			}
-			return (ISC_R_NOMEMORY);
-		}
 	} else {
 		ipseckey->key = NULL;
 	}
diff --git a/lib/dns/rdata/generic/isdn_20.c b/lib/dns/rdata/generic/isdn_20.c
index 6ab97ac3a1..f58c17e63d 100644
--- a/lib/dns/rdata/generic/isdn_20.c
+++ b/lib/dns/rdata/generic/isdn_20.c
@@ -146,9 +146,6 @@ tostruct_isdn(ARGS_TOSTRUCT) {
 	isdn->isdn_len = uint8_fromregion(&r);
 	isc_region_consume(&r, 1);
 	isdn->isdn = mem_maybedup(mctx, r.base, isdn->isdn_len);
-	if (isdn->isdn == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&r, isdn->isdn_len);
 
 	if (r.length == 0) {
@@ -159,19 +156,10 @@ tostruct_isdn(ARGS_TOSTRUCT) {
 		isc_region_consume(&r, 1);
 		isdn->subaddress = mem_maybedup(mctx, r.base,
 						isdn->subaddress_len);
-		if (isdn->subaddress == NULL) {
-			goto cleanup;
-		}
 	}
 
 	isdn->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL && isdn->isdn != NULL) {
-		isc_mem_free(mctx, isdn->isdn);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/key_25.c b/lib/dns/rdata/generic/key_25.c
index c6e3eefce6..688b6684ec 100644
--- a/lib/dns/rdata/generic/key_25.c
+++ b/lib/dns/rdata/generic/key_25.c
@@ -355,10 +355,6 @@ generic_tostruct_key(ARGS_TOSTRUCT) {
 	/* Data */
 	key->datalen = sr.length;
 	key->data = mem_maybedup(mctx, sr.base, key->datalen);
-	if (key->data == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	key->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/keydata_65533.c b/lib/dns/rdata/generic/keydata_65533.c
index 4bab60e4b7..c5670d01ab 100644
--- a/lib/dns/rdata/generic/keydata_65533.c
+++ b/lib/dns/rdata/generic/keydata_65533.c
@@ -384,10 +384,6 @@ tostruct_keydata(ARGS_TOSTRUCT) {
 	/* Data */
 	keydata->datalen = sr.length;
 	keydata->data = mem_maybedup(mctx, sr.base, keydata->datalen);
-	if (keydata->data == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	keydata->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/naptr_35.c b/lib/dns/rdata/generic/naptr_35.c
index e6ed027f17..6f78b73315 100644
--- a/lib/dns/rdata/generic/naptr_35.c
+++ b/lib/dns/rdata/generic/naptr_35.c
@@ -521,27 +521,18 @@ tostruct_naptr(ARGS_TOSTRUCT) {
 	isc_region_consume(&r, 1);
 	INSIST(naptr->flags_len <= r.length);
 	naptr->flags = mem_maybedup(mctx, r.base, naptr->flags_len);
-	if (naptr->flags == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&r, naptr->flags_len);
 
 	naptr->service_len = uint8_fromregion(&r);
 	isc_region_consume(&r, 1);
 	INSIST(naptr->service_len <= r.length);
 	naptr->service = mem_maybedup(mctx, r.base, naptr->service_len);
-	if (naptr->service == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&r, naptr->service_len);
 
 	naptr->regexp_len = uint8_fromregion(&r);
 	isc_region_consume(&r, 1);
 	INSIST(naptr->regexp_len <= r.length);
 	naptr->regexp = mem_maybedup(mctx, r.base, naptr->regexp_len);
-	if (naptr->regexp == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&r, naptr->regexp_len);
 
 	dns_name_init(&name, NULL);
@@ -550,18 +541,6 @@ tostruct_naptr(ARGS_TOSTRUCT) {
 	name_duporclone(&name, mctx, &naptr->replacement);
 	naptr->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL && naptr->flags != NULL) {
-		isc_mem_free(mctx, naptr->flags);
-	}
-	if (mctx != NULL && naptr->service != NULL) {
-		isc_mem_free(mctx, naptr->service);
-	}
-	if (mctx != NULL && naptr->regexp != NULL) {
-		isc_mem_free(mctx, naptr->regexp);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/nsec3_50.c b/lib/dns/rdata/generic/nsec3_50.c
index 8bc44f13c6..6960f75ea6 100644
--- a/lib/dns/rdata/generic/nsec3_50.c
+++ b/lib/dns/rdata/generic/nsec3_50.c
@@ -306,34 +306,17 @@ tostruct_nsec3(ARGS_TOSTRUCT) {
 	nsec3->salt_length = uint8_consume_fromregion(&region);
 	INSIST(nsec3->salt_length <= region.length);
 	nsec3->salt = mem_maybedup(mctx, region.base, nsec3->salt_length);
-	if (nsec3->salt == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&region, nsec3->salt_length);
 
 	nsec3->next_length = uint8_consume_fromregion(&region);
 	INSIST(nsec3->next_length <= region.length);
 	nsec3->next = mem_maybedup(mctx, region.base, nsec3->next_length);
-	if (nsec3->next == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&region, nsec3->next_length);
 
 	nsec3->len = region.length;
 	nsec3->typebits = mem_maybedup(mctx, region.base, region.length);
-	if (nsec3->typebits == NULL) {
-		goto cleanup;
-	}
-
 	nsec3->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (nsec3->next != NULL) {
-		isc_mem_free(mctx, nsec3->next);
-	}
-	isc_mem_free(mctx, nsec3->salt);
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/nsec3param_51.c b/lib/dns/rdata/generic/nsec3param_51.c
index bac40b45f5..43f9a4512b 100644
--- a/lib/dns/rdata/generic/nsec3param_51.c
+++ b/lib/dns/rdata/generic/nsec3param_51.c
@@ -243,9 +243,6 @@ tostruct_nsec3param(ARGS_TOSTRUCT) {
 	INSIST(nsec3param->salt_length == region.length);
 	nsec3param->salt = mem_maybedup(mctx, region.base,
 					nsec3param->salt_length);
-	if (nsec3param->salt == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	isc_region_consume(&region, nsec3param->salt_length);
 
 	nsec3param->mctx = mctx;
diff --git a/lib/dns/rdata/generic/nsec_47.c b/lib/dns/rdata/generic/nsec_47.c
index 96db05fea7..01044ead26 100644
--- a/lib/dns/rdata/generic/nsec_47.c
+++ b/lib/dns/rdata/generic/nsec_47.c
@@ -178,18 +178,8 @@ tostruct_nsec(ARGS_TOSTRUCT) {
 
 	nsec->len = region.length;
 	nsec->typebits = mem_maybedup(mctx, region.base, region.length);
-	if (nsec->typebits == NULL) {
-		goto cleanup;
-	}
-
 	nsec->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&nsec->next, mctx);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/null_10.c b/lib/dns/rdata/generic/null_10.c
index 126e361861..90ddd2234d 100644
--- a/lib/dns/rdata/generic/null_10.c
+++ b/lib/dns/rdata/generic/null_10.c
@@ -108,10 +108,6 @@ tostruct_null(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	null->length = r.length;
 	null->data = mem_maybedup(mctx, r.base, r.length);
-	if (null->data == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	null->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/nxt_30.c b/lib/dns/rdata/generic/nxt_30.c
index fa03bdf512..1cc4c822c3 100644
--- a/lib/dns/rdata/generic/nxt_30.c
+++ b/lib/dns/rdata/generic/nxt_30.c
@@ -257,18 +257,8 @@ tostruct_nxt(ARGS_TOSTRUCT) {
 
 	nxt->len = region.length;
 	nxt->typebits = mem_maybedup(mctx, region.base, region.length);
-	if (nxt->typebits == NULL) {
-		goto cleanup;
-	}
-
 	nxt->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&nxt->next, mctx);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/openpgpkey_61.c b/lib/dns/rdata/generic/openpgpkey_61.c
index b6db9d758b..6beef9e491 100644
--- a/lib/dns/rdata/generic/openpgpkey_61.c
+++ b/lib/dns/rdata/generic/openpgpkey_61.c
@@ -156,15 +156,8 @@ tostruct_openpgpkey(ARGS_TOSTRUCT) {
 	 */
 	sig->length = sr.length;
 	sig->keyring = mem_maybedup(mctx, sr.base, sig->length);
-	if (sig->keyring == NULL) {
-		goto cleanup;
-	}
-
 	sig->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/opt_41.c b/lib/dns/rdata/generic/opt_41.c
index 1ac13764b7..6e82d3abdd 100644
--- a/lib/dns/rdata/generic/opt_41.c
+++ b/lib/dns/rdata/generic/opt_41.c
@@ -330,10 +330,6 @@ tostruct_opt(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	opt->length = r.length;
 	opt->options = mem_maybedup(mctx, r.base, r.length);
-	if (opt->options == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	opt->offset = 0;
 	opt->mctx = mctx;
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/rdata/generic/rrsig_46.c b/lib/dns/rdata/generic/rrsig_46.c
index 1239d93cf1..a74675b2e6 100644
--- a/lib/dns/rdata/generic/rrsig_46.c
+++ b/lib/dns/rdata/generic/rrsig_46.c
@@ -501,18 +501,8 @@ tostruct_rrsig(ARGS_TOSTRUCT) {
 	 */
 	sig->siglen = sr.length;
 	sig->signature = mem_maybedup(mctx, sr.base, sig->siglen);
-	if (sig->signature == NULL) {
-		goto cleanup;
-	}
-
 	sig->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&sig->signer, mctx);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/sig_24.c b/lib/dns/rdata/generic/sig_24.c
index 369369608d..c585dfabda 100644
--- a/lib/dns/rdata/generic/sig_24.c
+++ b/lib/dns/rdata/generic/sig_24.c
@@ -493,18 +493,8 @@ tostruct_sig(ARGS_TOSTRUCT) {
 	 */
 	sig->siglen = sr.length;
 	sig->signature = mem_maybedup(mctx, sr.base, sig->siglen);
-	if (sig->signature == NULL) {
-		goto cleanup;
-	}
-
 	sig->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&sig->signer, mctx);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/sink_40.c b/lib/dns/rdata/generic/sink_40.c
index 2120a4a6a4..38104cf90c 100644
--- a/lib/dns/rdata/generic/sink_40.c
+++ b/lib/dns/rdata/generic/sink_40.c
@@ -214,10 +214,6 @@ tostruct_sink(ARGS_TOSTRUCT) {
 	/* Data */
 	sink->datalen = sr.length;
 	sink->data = mem_maybedup(mctx, sr.base, sink->datalen);
-	if (sink->data == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	sink->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/sshfp_44.c b/lib/dns/rdata/generic/sshfp_44.c
index d71a3963eb..5a214f326f 100644
--- a/lib/dns/rdata/generic/sshfp_44.c
+++ b/lib/dns/rdata/generic/sshfp_44.c
@@ -218,10 +218,6 @@ tostruct_sshfp(ARGS_TOSTRUCT) {
 	sshfp->length = region.length;
 
 	sshfp->digest = mem_maybedup(mctx, region.base, region.length);
-	if (sshfp->digest == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	sshfp->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/tkey_249.c b/lib/dns/rdata/generic/tkey_249.c
index 66ad6c4445..675b827365 100644
--- a/lib/dns/rdata/generic/tkey_249.c
+++ b/lib/dns/rdata/generic/tkey_249.c
@@ -474,9 +474,6 @@ tostruct_tkey(ARGS_TOSTRUCT) {
 	 */
 	INSIST(tkey->keylen + 2U <= sr.length);
 	tkey->key = mem_maybedup(mctx, sr.base, tkey->keylen);
-	if (tkey->key == NULL) {
-		goto cleanup;
-	}
 	isc_region_consume(&sr, tkey->keylen);
 
 	/*
@@ -490,21 +487,8 @@ tostruct_tkey(ARGS_TOSTRUCT) {
 	 */
 	INSIST(tkey->otherlen <= sr.length);
 	tkey->other = mem_maybedup(mctx, sr.base, tkey->otherlen);
-	if (tkey->other == NULL) {
-		goto cleanup;
-	}
-
 	tkey->mctx = mctx;
 	return (ISC_R_SUCCESS);
-
-cleanup:
-	if (mctx != NULL) {
-		dns_name_free(&tkey->algorithm, mctx);
-	}
-	if (mctx != NULL && tkey->key != NULL) {
-		isc_mem_free(mctx, tkey->key);
-	}
-	return (ISC_R_NOMEMORY);
 }
 
 static inline void
diff --git a/lib/dns/rdata/generic/tlsa_52.c b/lib/dns/rdata/generic/tlsa_52.c
index 65a4f7fe13..298aae0040 100644
--- a/lib/dns/rdata/generic/tlsa_52.c
+++ b/lib/dns/rdata/generic/tlsa_52.c
@@ -231,10 +231,6 @@ generic_tostruct_tlsa(ARGS_TOSTRUCT) {
 	tlsa->length = region.length;
 
 	tlsa->data = mem_maybedup(mctx, region.base, region.length);
-	if (tlsa->data == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	tlsa->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/txt_16.c b/lib/dns/rdata/generic/txt_16.c
index 73b3f0c899..36d75b491a 100644
--- a/lib/dns/rdata/generic/txt_16.c
+++ b/lib/dns/rdata/generic/txt_16.c
@@ -172,10 +172,6 @@ generic_tostruct_txt(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	txt->txt_len = r.length;
 	txt->txt = mem_maybedup(mctx, r.base, r.length);
-	if (txt->txt == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	txt->offset = 0;
 	txt->mctx = mctx;
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/rdata/generic/uri_256.c b/lib/dns/rdata/generic/uri_256.c
index 626a34e2a0..a613e4d9bb 100644
--- a/lib/dns/rdata/generic/uri_256.c
+++ b/lib/dns/rdata/generic/uri_256.c
@@ -240,10 +240,6 @@ tostruct_uri(ARGS_TOSTRUCT) {
 	 */
 	uri->tgt_len = sr.length;
 	uri->target = mem_maybedup(mctx, sr.base, sr.length);
-	if (uri->target == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	uri->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/x25_19.c b/lib/dns/rdata/generic/x25_19.c
index 63f6be827f..f754443e63 100644
--- a/lib/dns/rdata/generic/x25_19.c
+++ b/lib/dns/rdata/generic/x25_19.c
@@ -154,10 +154,6 @@ tostruct_x25(ARGS_TOSTRUCT) {
 	x25->x25_len = uint8_fromregion(&r);
 	isc_region_consume(&r, 1);
 	x25->x25 = mem_maybedup(mctx, r.base, x25->x25_len);
-	if (x25->x25 == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	x25->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/generic/zonemd_63.c b/lib/dns/rdata/generic/zonemd_63.c
index f09ee5229c..8c8625e8f4 100644
--- a/lib/dns/rdata/generic/zonemd_63.c
+++ b/lib/dns/rdata/generic/zonemd_63.c
@@ -272,10 +272,6 @@ tostruct_zonemd(ARGS_TOSTRUCT) {
 	zonemd->length = region.length;
 
 	zonemd->digest = mem_maybedup(mctx, region.base, region.length);
-	if (zonemd->digest == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	zonemd->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/in_1/apl_42.c b/lib/dns/rdata/in_1/apl_42.c
index 7885af233b..bda153cd20 100644
--- a/lib/dns/rdata/in_1/apl_42.c
+++ b/lib/dns/rdata/in_1/apl_42.c
@@ -295,10 +295,6 @@ tostruct_in_apl(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	apl->apl_len = r.length;
 	apl->apl = mem_maybedup(mctx, r.base, r.length);
-	if (apl->apl == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	apl->offset = 0;
 	apl->mctx = mctx;
 	return (ISC_R_SUCCESS);
diff --git a/lib/dns/rdata/in_1/atma_34.c b/lib/dns/rdata/in_1/atma_34.c
index 30580d3056..c5f03c221f 100644
--- a/lib/dns/rdata/in_1/atma_34.c
+++ b/lib/dns/rdata/in_1/atma_34.c
@@ -234,10 +234,6 @@ tostruct_in_atma(ARGS_TOSTRUCT) {
 	isc_region_consume(&r, 1);
 	atma->atma_len = r.length;
 	atma->atma = mem_maybedup(mctx, r.base, r.length);
-	if (atma->atma == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	atma->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/in_1/dhcid_49.c b/lib/dns/rdata/in_1/dhcid_49.c
index ca3c393739..dd83c51a40 100644
--- a/lib/dns/rdata/in_1/dhcid_49.c
+++ b/lib/dns/rdata/in_1/dhcid_49.c
@@ -152,10 +152,6 @@ tostruct_in_dhcid(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &region);
 
 	dhcid->dhcid = mem_maybedup(mctx, region.base, region.length);
-	if (dhcid->dhcid == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	dhcid->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/in_1/eid_31.c b/lib/dns/rdata/in_1/eid_31.c
index 38a3887f3f..e71fda1af4 100644
--- a/lib/dns/rdata/in_1/eid_31.c
+++ b/lib/dns/rdata/in_1/eid_31.c
@@ -141,10 +141,6 @@ tostruct_in_eid(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	eid->eid_len = r.length;
 	eid->eid = mem_maybedup(mctx, r.base, r.length);
-	if (eid->eid == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	eid->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/in_1/nimloc_32.c b/lib/dns/rdata/in_1/nimloc_32.c
index d96967f6bd..f6045c5ace 100644
--- a/lib/dns/rdata/in_1/nimloc_32.c
+++ b/lib/dns/rdata/in_1/nimloc_32.c
@@ -141,10 +141,6 @@ tostruct_in_nimloc(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	nimloc->nimloc_len = r.length;
 	nimloc->nimloc = mem_maybedup(mctx, r.base, r.length);
-	if (nimloc->nimloc == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	nimloc->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }
diff --git a/lib/dns/rdata/in_1/nsap_22.c b/lib/dns/rdata/in_1/nsap_22.c
index 379842346f..22be56e2da 100644
--- a/lib/dns/rdata/in_1/nsap_22.c
+++ b/lib/dns/rdata/in_1/nsap_22.c
@@ -176,10 +176,6 @@ tostruct_in_nsap(ARGS_TOSTRUCT) {
 	dns_rdata_toregion(rdata, &r);
 	nsap->nsap_len = r.length;
 	nsap->nsap = mem_maybedup(mctx, r.base, r.length);
-	if (nsap->nsap == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
-
 	nsap->mctx = mctx;
 	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 e783f06083..b2b8657b97 100644
--- a/lib/dns/rdata/in_1/svcb_64.c
+++ b/lib/dns/rdata/in_1/svcb_64.c
@@ -1014,13 +1014,6 @@ generic_tostruct_in_svcb(ARGS_TOSTRUCT) {
 	svcb->svclen = region.length;
 	svcb->svc = mem_maybedup(mctx, region.base, region.length);
 
-	if (svcb->svc == NULL) {
-		if (mctx != NULL) {
-			dns_name_free(&svcb->svcdomain, svcb->mctx);
-		}
-		return (ISC_R_NOMEMORY);
-	}
-
 	svcb->offset = 0;
 	svcb->mctx = mctx;
 
diff --git a/lib/dns/rdata/in_1/wks_11.c b/lib/dns/rdata/in_1/wks_11.c
index 66883beeb2..f8567e6ec7 100644
--- a/lib/dns/rdata/in_1/wks_11.c
+++ b/lib/dns/rdata/in_1/wks_11.c
@@ -323,9 +323,6 @@ tostruct_in_wks(ARGS_TOSTRUCT) {
 	isc_region_consume(&region, 1);
 	wks->map_len = region.length;
 	wks->map = mem_maybedup(mctx, region.base, region.length);
-	if (wks->map == NULL) {
-		return (ISC_R_NOMEMORY);
-	}
 	wks->mctx = mctx;
 	return (ISC_R_SUCCESS);
 }