diff --git a/tests/tests-asn1c-compiler/104-param-1-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/104-param-1-OK.asn1.-Pfwide-types
index 7de1b8a..c5b7465 100644
--- a/tests/tests-asn1c-compiler/104-param-1-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/104-param-1-OK.asn1.-Pfwide-types
@@ -157,8 +157,7 @@
 	.tag2el = asn_MAP_Bunch_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Bunch = {
 	"Bunch",
diff --git a/tests/tests-asn1c-compiler/105-param-2-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/105-param-2-OK.asn1.-Pfwide-types
index 05b2a8e..0535c89 100644
--- a/tests/tests-asn1c-compiler/105-param-2-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/105-param-2-OK.asn1.-Pfwide-types
@@ -74,8 +74,7 @@
 	.tag2el = asn_MAP_SIGNED_16P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SIGNED_16P0 = {
 	"SIGNED",
@@ -165,8 +164,7 @@
 	.tag2el = asn_MAP_SIGNED_16P1_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SIGNED_16P1 = {
 	"SIGNED",
diff --git a/tests/tests-asn1c-compiler/106-param-constr-OK.asn1.-P b/tests/tests-asn1c-compiler/106-param-constr-OK.asn1.-P
index 7c96a85..1ba2161 100644
--- a/tests/tests-asn1c-compiler/106-param-constr-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/106-param-constr-OK.asn1.-P
@@ -167,8 +167,7 @@
 	.tag2el = asn_MAP_Narrow_15P0_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Narrow_15P0 = {
 	"Narrow",
diff --git a/tests/tests-asn1c-compiler/110-param-3-OK.asn1.-Pfcompound-names b/tests/tests-asn1c-compiler/110-param-3-OK.asn1.-Pfcompound-names
index 2b9b7e0..90d94db 100644
--- a/tests/tests-asn1c-compiler/110-param-3-OK.asn1.-Pfcompound-names
+++ b/tests/tests-asn1c-compiler/110-param-3-OK.asn1.-Pfcompound-names
@@ -98,8 +98,7 @@
 	.tag2el = asn_MAP_Flag_15P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Flag_15P0 = {
 	"Flag",
@@ -201,8 +200,7 @@
 	.tag2el = asn_MAP_Flag_15P1_tag2el_6,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Flag_15P1 = {
 	"Flag",
diff --git a/tests/tests-asn1c-compiler/119-per-strings-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/119-per-strings-OK.asn1.-Pgen-PER
index 8b04894..8f91298 100644
--- a/tests/tests-asn1c-compiler/119-per-strings-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/119-per-strings-OK.asn1.-Pgen-PER
@@ -1545,8 +1545,7 @@
 	.tag2el_count = 31,	/* Count of tags in the map */
 	asn_MAP_PDU_oms_1,	/* Optional members */
 	31, 0,	/* Root/Additions */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_PDU = {
 	"PDU",
diff --git a/tests/tests-asn1c-compiler/126-per-extensions-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/126-per-extensions-OK.asn1.-Pgen-PER
index 1490669..e5bf8c6 100644
--- a/tests/tests-asn1c-compiler/126-per-extensions-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/126-per-extensions-OK.asn1.-Pgen-PER
@@ -91,8 +91,7 @@
 	.tag2el_count = 4,	/* Count of tags in the map */
 	asn_MAP_PDU_oms_1,	/* Optional members */
 	0, 4,	/* Root/Additions */
-	-1,	/* Start extensions */
-	5	/* Stop extensions */
+	0,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_PDU = {
 	"PDU",
@@ -191,8 +190,7 @@
 	.tag2el_count = 1,	/* Count of tags in the map */
 	asn_MAP_Singleton_oms_1,	/* Optional members */
 	1, 0,	/* Root/Additions */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Singleton = {
 	"Singleton",
@@ -306,7 +304,7 @@
 	.tag2el_count = 3,	/* Count of tags in the map */
 	.to_canonical_order = asn_MAP_PDU_2_to_canonical_1,
 	.from_canonical_order = asn_MAP_PDU_2_from_canonical_1,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_PDU_2 = {
 	"PDU-2",
diff --git a/tests/tests-asn1c-compiler/127-per-long-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/127-per-long-OK.asn1.-Pgen-PER
index 40c39f8..5700eeb 100644
--- a/tests/tests-asn1c-compiler/127-per-long-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/127-per-long-OK.asn1.-Pgen-PER
@@ -303,8 +303,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/131-per-empty-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/131-per-empty-OK.asn1.-Pgen-PER
index 1cbc801..829dc4d 100644
--- a/tests/tests-asn1c-compiler/131-per-empty-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/131-per-empty-OK.asn1.-Pgen-PER
@@ -26,8 +26,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/134-per-long-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/134-per-long-OK.asn1.-Pgen-PER
index 17670fa..df46a74 100644
--- a/tests/tests-asn1c-compiler/134-per-long-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/134-per-long-OK.asn1.-Pgen-PER
@@ -225,8 +225,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/136-oer-long-OK.asn1.-Pgen-OER b/tests/tests-asn1c-compiler/136-oer-long-OK.asn1.-Pgen-OER
index 28a9055..e449bea 100644
--- a/tests/tests-asn1c-compiler/136-oer-long-OK.asn1.-Pgen-OER
+++ b/tests/tests-asn1c-compiler/136-oer-long-OK.asn1.-Pgen-OER
@@ -541,8 +541,7 @@
 	.tag2el_count = 12,	/* Count of tags in the map */
 	asn_MAP_T_oms_1,	/* Optional members */
 	1, 6,	/* Root/Additions */
-	5,	/* Start extensions */
-	13	/* Stop extensions */
+	6,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/137-oer-string-OK.asn1.-Pgen-OER b/tests/tests-asn1c-compiler/137-oer-string-OK.asn1.-Pgen-OER
index 0f75e76..6277490 100644
--- a/tests/tests-asn1c-compiler/137-oer-string-OK.asn1.-Pgen-OER
+++ b/tests/tests-asn1c-compiler/137-oer-string-OK.asn1.-Pgen-OER
@@ -213,8 +213,7 @@
 	.tag2el = asn_MAP_unconstrained_tag2el_2,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_unconstrained_2 = {
@@ -276,8 +275,7 @@
 	.tag2el = asn_MAP_constrained_tag2el_6,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_constrained_6 = {
@@ -329,8 +327,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/139-component-relation-OK.asn1.-P b/tests/tests-asn1c-compiler/139-component-relation-OK.asn1.-P
index 89468a4..b732a46 100644
--- a/tests/tests-asn1c-compiler/139-component-relation-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/139-component-relation-OK.asn1.-P
@@ -157,7 +157,7 @@
 	.tag2el = asn_MAP_value_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_3 = {
@@ -206,8 +206,7 @@
 	.tag2el = asn_MAP_Frame_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Frame = {
 	"Frame",
@@ -254,8 +253,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_PrimitiveMessage = {
 	"PrimitiveMessage",
@@ -301,8 +299,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ComplexMessage = {
 	"ComplexMessage",
diff --git a/tests/tests-asn1c-compiler/140-component-relation-OK.asn1.-P b/tests/tests-asn1c-compiler/140-component-relation-OK.asn1.-P
index 89468a4..b732a46 100644
--- a/tests/tests-asn1c-compiler/140-component-relation-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/140-component-relation-OK.asn1.-P
@@ -157,7 +157,7 @@
 	.tag2el = asn_MAP_value_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_3 = {
@@ -206,8 +206,7 @@
 	.tag2el = asn_MAP_Frame_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Frame = {
 	"Frame",
@@ -254,8 +253,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_PrimitiveMessage = {
 	"PrimitiveMessage",
@@ -301,8 +299,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ComplexMessage = {
 	"ComplexMessage",
diff --git a/tests/tests-asn1c-compiler/141-component-relation-OK.asn1.-P b/tests/tests-asn1c-compiler/141-component-relation-OK.asn1.-P
index 9befb07..b3e7e4f 100644
--- a/tests/tests-asn1c-compiler/141-component-relation-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/141-component-relation-OK.asn1.-P
@@ -163,7 +163,7 @@
 	.tag2el = asn_MAP_value_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_3 = {
@@ -213,8 +213,7 @@
 	.tag2el = asn_MAP_Frame_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Frame = {
 	"Frame",
@@ -333,8 +332,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_PrimitiveMessage = {
 	"PrimitiveMessage",
@@ -380,8 +378,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ComplexMessage = {
 	"ComplexMessage",
diff --git a/tests/tests-asn1c-compiler/142-anonymous-types-deco-OK.asn1.-Pfcompound-names b/tests/tests-asn1c-compiler/142-anonymous-types-deco-OK.asn1.-Pfcompound-names
index 30be937..1d2ee81 100644
--- a/tests/tests-asn1c-compiler/142-anonymous-types-deco-OK.asn1.-Pfcompound-names
+++ b/tests/tests-asn1c-compiler/142-anonymous-types-deco-OK.asn1.-Pfcompound-names
@@ -64,7 +64,7 @@
 	.tag2el = asn_MAP_CommonType_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_CommonType = {
 	"CommonType",
@@ -209,8 +209,7 @@
 	.tag2el = asn_MAP_anonType_tag2el_2,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_anonType_2 = {
@@ -251,7 +250,7 @@
 	.tag2el = asn_MAP_Type1_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Type1 = {
 	"Type1",
@@ -396,8 +395,7 @@
 	.tag2el = asn_MAP_anonType_tag2el_2,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_anonType_2 = {
@@ -438,7 +436,7 @@
 	.tag2el = asn_MAP_Type2_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Type2 = {
 	"Type2",
diff --git a/tests/tests-asn1c-compiler/143-inner-parameterization-OK.asn1.-P b/tests/tests-asn1c-compiler/143-inner-parameterization-OK.asn1.-P
index 01dab4e..0a50ab8 100644
--- a/tests/tests-asn1c-compiler/143-inner-parameterization-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/143-inner-parameterization-OK.asn1.-P
@@ -53,8 +53,7 @@
 	.tag2el = asn_MAP_Message_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Message = {
 	"Message",
@@ -180,8 +179,7 @@
 	.tag2el = asn_MAP_SpecializedContent_21P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SpecializedContent_21P0 = {
 	"SpecializedContent",
@@ -222,8 +220,7 @@
 	.tag2el = asn_MAP_SpecializedContent_21P1_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SpecializedContent_21P1 = {
 	"SpecializedContent",
diff --git a/tests/tests-asn1c-compiler/144-ios-parameterization-OK.asn1.-P b/tests/tests-asn1c-compiler/144-ios-parameterization-OK.asn1.-P
index 9020ba7..89a6699 100644
--- a/tests/tests-asn1c-compiler/144-ios-parameterization-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/144-ios-parameterization-OK.asn1.-P
@@ -42,8 +42,7 @@
 	.tag2el = asn_MAP_Message_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Message = {
 	"Message",
@@ -217,7 +216,7 @@
 	.tag2el = asn_MAP_value_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_3 = {
@@ -266,8 +265,7 @@
 	.tag2el = asn_MAP_SpecializedContent_30P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SpecializedContent_30P0 = {
 	"SpecializedContent",
diff --git a/tests/tests-asn1c-compiler/146-ios-parameterization-per-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/146-ios-parameterization-per-OK.asn1.-Pgen-PER
index b232b5b..5e59610 100644
--- a/tests/tests-asn1c-compiler/146-ios-parameterization-per-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/146-ios-parameterization-per-OK.asn1.-Pgen-PER
@@ -42,8 +42,7 @@
 	.tag2el = asn_MAP_Message_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Message = {
 	"Message",
@@ -233,7 +232,7 @@
 	.tag2el_count = 2,	/* Count of tags in the map */
 	.to_canonical_order = asn_MAP_value_to_canonical_3,
 	.from_canonical_order = asn_MAP_value_from_canonical_3,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_3 = {
@@ -282,8 +281,7 @@
 	.tag2el = asn_MAP_SpecializedContent_30P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SpecializedContent_30P0 = {
 	"SpecializedContent",
diff --git a/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-OER b/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-OER
index b8e9b11..ec984ce 100644
--- a/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-OER
+++ b/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-OER
@@ -260,8 +260,7 @@
 	.tag2el = asn_MAP_Soo_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Soo = {
 	"Soo",
diff --git a/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-PER
index c4cfef0..fd7c39e 100644
--- a/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/147-inherit-per-constraints-OK.asn1.-Pgen-PER
@@ -268,8 +268,7 @@
 	.tag2el = asn_MAP_Soo_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Soo = {
 	"Soo",
diff --git a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pfwide-types
index 6b10989..9403b97 100644
--- a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pfwide-types
@@ -904,8 +904,7 @@
 	.tag2el = asn_MAP_Test_tag2el_1,
 	.tag2el_count = 7,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Test = {
 	"Test",
diff --git a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-OER b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-OER
index 508ccbc..71cb428 100644
--- a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-OER
+++ b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-OER
@@ -979,8 +979,7 @@
 	.tag2el = asn_MAP_Test_tag2el_1,
 	.tag2el_count = 7,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Test = {
 	"Test",
diff --git a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-PER
index 7ba0c05..2858cc3 100644
--- a/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/154-with-REAL-components-OK.asn1.-Pgen-PER
@@ -1010,8 +1010,7 @@
 	.tag2el = asn_MAP_Test_tag2el_1,
 	.tag2el_count = 7,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Test = {
 	"Test",
diff --git a/tests/tests-asn1c-compiler/155-parameterization-more-than-two-level-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/155-parameterization-more-than-two-level-OK.asn1.-Pgen-PER
index df71c35..1a5121f 100644
--- a/tests/tests-asn1c-compiler/155-parameterization-more-than-two-level-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/155-parameterization-more-than-two-level-OK.asn1.-Pgen-PER
@@ -689,7 +689,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_value_4 = {
@@ -747,8 +747,7 @@
 	.tag2el = asn_MAP_Packet_51P0_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Packet_51P0 = {
 	"Packet",
diff --git a/tests/tests-asn1c-compiler/157-per-canonical-order-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/157-per-canonical-order-OK.asn1.-Pgen-PER
index e17c392..ba6520c 100644
--- a/tests/tests-asn1c-compiler/157-per-canonical-order-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/157-per-canonical-order-OK.asn1.-Pgen-PER
@@ -98,7 +98,7 @@
 	.tag2el_count = 4,	/* Count of tags in the map */
 	.to_canonical_order = asn_MAP_T_to_canonical_1,
 	.from_canonical_order = asn_MAP_T_from_canonical_1,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/19-param-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/19-param-OK.asn1.-Pfwide-types
index 1c16740..2e9ee7f 100644
--- a/tests/tests-asn1c-compiler/19-param-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/19-param-OK.asn1.-Pfwide-types
@@ -110,8 +110,7 @@
 	.tag2el = asn_MAP_toBeSigned_tag2el_2,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_toBeSigned_2 = {
@@ -173,8 +172,7 @@
 	.tag2el = asn_MAP_SIGNED_15P0_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SIGNED_15P0 = {
 	"SIGNED",
diff --git a/tests/tests-asn1c-compiler/22-tags-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/22-tags-OK.asn1.-Pfwide-types
index dd286a5..e9d863d 100644
--- a/tests/tests-asn1c-compiler/22-tags-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/22-tags-OK.asn1.-Pfwide-types
@@ -73,7 +73,7 @@
 	.tag2el = asn_MAP_b_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_b_3 = {
@@ -133,8 +133,7 @@
 	.tag2el = asn_MAP_T1_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T1 = {
 	"T1",
diff --git a/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfcompound-names b/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfcompound-names
index 0169848..fc39f33 100644
--- a/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfcompound-names
+++ b/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfcompound-names
@@ -121,8 +121,7 @@
 	.tag2el = asn_MAP_Tree_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Tree = {
 	"Tree",
@@ -293,8 +292,7 @@
 	.tag2el = asn_MAP_Member_tag2el_5,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	0,	/* Start extensions */
-	2	/* Stop extensions */
+	1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_Member_5 = {
@@ -382,7 +380,7 @@
 	.tag2el = asn_MAP_other_tag2el_9,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_other_9 = {
diff --git a/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfwide-types
index cbb8e90..2a4cf8f 100644
--- a/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/31-set-of-OK.asn1.-Pfwide-types
@@ -121,8 +121,7 @@
 	.tag2el = asn_MAP_Tree_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Tree = {
 	"Tree",
@@ -293,8 +292,7 @@
 	.tag2el = asn_MAP_Member_tag2el_5,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	0,	/* Start extensions */
-	2	/* Stop extensions */
+	1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_Member_5 = {
@@ -382,7 +380,7 @@
 	.tag2el = asn_MAP_other_tag2el_9,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_other_9 = {
diff --git a/tests/tests-asn1c-compiler/32-sequence-of-OK.asn1.-P b/tests/tests-asn1c-compiler/32-sequence-of-OK.asn1.-P
index b75a93b..2f73414 100644
--- a/tests/tests-asn1c-compiler/32-sequence-of-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/32-sequence-of-OK.asn1.-P
@@ -161,8 +161,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Error = {
 	"Error",
@@ -286,8 +285,7 @@
 	.tag2el = asn_MAP_SeqWithMandatory_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SeqWithMandatory = {
 	"SeqWithMandatory",
@@ -412,8 +410,7 @@
 	.tag2el = asn_MAP_SeqWithOptional_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_SeqWithOptional = {
 	"SeqWithOptional",
diff --git a/tests/tests-asn1c-compiler/37-indirect-choice-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/37-indirect-choice-OK.asn1.-Pfwide-types
index 44ec422..b1ea6bf 100644
--- a/tests/tests-asn1c-compiler/37-indirect-choice-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/37-indirect-choice-OK.asn1.-Pfwide-types
@@ -90,7 +90,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
@@ -174,7 +174,7 @@
 	.tag2el = asn_MAP_Choice1_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice1 = {
 	"Choice1",
@@ -286,7 +286,7 @@
 	.tag2el = asn_MAP_Choice2_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice2 = {
 	"Choice2",
diff --git a/tests/tests-asn1c-compiler/39-sequence-of-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/39-sequence-of-OK.asn1.-Pfwide-types
index 4a298ec..c535515 100644
--- a/tests/tests-asn1c-compiler/39-sequence-of-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/39-sequence-of-OK.asn1.-Pfwide-types
@@ -104,8 +104,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
@@ -181,8 +180,7 @@
 	.tag2el = asn_MAP_T2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T2 = {
 	"T2",
diff --git a/tests/tests-asn1c-compiler/42-real-life-OK.asn1.-PR b/tests/tests-asn1c-compiler/42-real-life-OK.asn1.-PR
index 84d06a1..b27e77a 100644
--- a/tests/tests-asn1c-compiler/42-real-life-OK.asn1.-PR
+++ b/tests/tests-asn1c-compiler/42-real-life-OK.asn1.-PR
@@ -137,8 +137,7 @@
 	.tag2el = asn_MAP_LogLine_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_LogLine = {
 	"LogLine",
@@ -290,8 +289,7 @@
 	.tag2el = asn_MAP_VariablePartSet_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_VariablePartSet = {
 	"VariablePartSet",
@@ -466,8 +464,7 @@
 	.tag2el = asn_MAP_vrange_tag2el_4,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_vrange_4 = {
@@ -518,7 +515,7 @@
 	.tag2el = asn_MAP_VariablePart_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 2	/* Extensions start */
+	.first_extension = 2	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_VariablePart = {
 	"VariablePart",
@@ -709,8 +706,7 @@
 	.tag2el = asn_MAP_notify_tag2el_7,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_notify_7 = {
@@ -762,8 +758,7 @@
 	.tag2el = asn_MAP_ActionItem_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	3	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ActionItem = {
 	"ActionItem",
diff --git a/tests/tests-asn1c-compiler/43-recursion-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/43-recursion-OK.asn1.-Pfwide-types
index c51e633..bdf973b 100644
--- a/tests/tests-asn1c-compiler/43-recursion-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/43-recursion-OK.asn1.-Pfwide-types
@@ -171,8 +171,7 @@
 	.tag2el = asn_MAP_Test_structure_1_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Test_structure_1 = {
 	"Test-structure-1",
@@ -333,7 +332,7 @@
 	.tag2el = asn_MAP_Choice_1_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice_1 = {
 	"Choice-1",
diff --git a/tests/tests-asn1c-compiler/44-choice-in-sequence-OK.asn1.-P b/tests/tests-asn1c-compiler/44-choice-in-sequence-OK.asn1.-P
index e9f4993..003c11a 100644
--- a/tests/tests-asn1c-compiler/44-choice-in-sequence-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/44-choice-in-sequence-OK.asn1.-P
@@ -102,7 +102,7 @@
 	.tag2el = asn_MAP_e_tag2el_6,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_e_6 = {
@@ -151,7 +151,7 @@
 	.tag2el = asn_MAP_h_tag2el_9,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_h_9 = {
@@ -221,7 +221,7 @@
 	.tag2el = asn_MAP_b_tag2el_3,
 	.tag2el_count = 5,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_b_3 = {
@@ -276,8 +276,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 6,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/46-redefine-OK.asn1.-PR b/tests/tests-asn1c-compiler/46-redefine-OK.asn1.-PR
index f7edb4c..ea18361 100644
--- a/tests/tests-asn1c-compiler/46-redefine-OK.asn1.-PR
+++ b/tests/tests-asn1c-compiler/46-redefine-OK.asn1.-PR
@@ -91,8 +91,7 @@
 	.tag2el = asn_MAP_ConstructedType_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ConstructedType = {
 	"ConstructedType",
diff --git a/tests/tests-asn1c-compiler/47-set-ext-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/47-set-ext-OK.asn1.-Pfwide-types
index 1a55fe8..5aca445 100644
--- a/tests/tests-asn1c-compiler/47-set-ext-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/47-set-ext-OK.asn1.-Pfwide-types
@@ -231,7 +231,7 @@
 	.tag2el = asn_MAP_T3_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T3 = {
 	"T3",
@@ -306,7 +306,7 @@
 	.tag2el = asn_MAP_T4_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T4 = {
 	"T4",
diff --git a/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pfwide-types
index 16b63d3..a0aff4a 100644
--- a/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pfwide-types
@@ -2197,8 +2197,7 @@
 	.tag2el = asn_MAP_Sequence_tag2el_1,
 	.tag2el_count = 7,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	5,	/* Start extensions */
-	8	/* Stop extensions */
+	6,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
diff --git a/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pgen-PER
index 25035fd..50a674e 100644
--- a/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/50-constraint-OK.asn1.-Pgen-PER
@@ -2427,8 +2427,7 @@
 	.tag2el_count = 7,	/* Count of tags in the map */
 	asn_MAP_Sequence_oms_1,	/* Optional members */
 	3, 1,	/* Root/Additions */
-	5,	/* Start extensions */
-	8	/* Stop extensions */
+	6,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
diff --git a/tests/tests-asn1c-compiler/59-choice-extended-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/59-choice-extended-OK.asn1.-Pfwide-types
index e2dab3c..16122b8 100644
--- a/tests/tests-asn1c-compiler/59-choice-extended-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/59-choice-extended-OK.asn1.-Pfwide-types
@@ -93,7 +93,7 @@
 	.tag2el = asn_MAP_Choice_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice = {
 	"Choice",
diff --git a/tests/tests-asn1c-compiler/60-any-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/60-any-OK.asn1.-Pfwide-types
index 8e5ee2d..5c21afa 100644
--- a/tests/tests-asn1c-compiler/60-any-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/60-any-OK.asn1.-Pfwide-types
@@ -53,8 +53,7 @@
 	.tag2el = asn_MAP_T1_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T1 = {
 	"T1",
@@ -128,8 +127,7 @@
 	.tag2el = asn_MAP_T2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T2 = {
 	"T2",
@@ -198,8 +196,7 @@
 	0,	/* No top level tags */
 	0,	/* No tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T3 = {
 	"T3",
diff --git a/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfnative-types b/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfnative-types
index 1d99041..aee1948 100644
--- a/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfnative-types
+++ b/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfnative-types
@@ -430,8 +430,7 @@
 	.tag2el = asn_MAP_Ts_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Ts = {
 	"Ts",
diff --git a/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfwide-types
index 30cc719..a04cdda 100644
--- a/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/65-multi-tag-OK.asn1.-Pfwide-types
@@ -430,8 +430,7 @@
 	.tag2el = asn_MAP_Ts_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Ts = {
 	"Ts",
diff --git a/tests/tests-asn1c-compiler/69-reserved-words-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/69-reserved-words-OK.asn1.-Pfwide-types
index 063aa6e..b732292 100644
--- a/tests/tests-asn1c-compiler/69-reserved-words-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/69-reserved-words-OK.asn1.-Pfwide-types
@@ -162,8 +162,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/70-xer-test-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/70-xer-test-OK.asn1.-Pfwide-types
index ac22bc8..7879a7c 100644
--- a/tests/tests-asn1c-compiler/70-xer-test-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/70-xer-test-OK.asn1.-Pfwide-types
@@ -239,7 +239,7 @@
 	.tag2el = asn_MAP_PDU_tag2el_1,
 	.tag2el_count = 15,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 15	/* Extensions start */
+	.first_extension = 15	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_PDU = {
 	"PDU",
@@ -344,8 +344,7 @@
 	.tag2el = asn_MAP_Sequence_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
@@ -684,8 +683,7 @@
 	.tag2el = asn_MAP_ExtensibleSequence_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	0,	/* Start extensions */
-	4	/* Stop extensions */
+	1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ExtensibleSequence = {
 	"ExtensibleSequence",
@@ -765,8 +763,7 @@
 	.tag2el = asn_MAP_ExtensibleSequence2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	0,	/* Start extensions */
-	3	/* Stop extensions */
+	1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_ExtensibleSequence2 = {
 	"ExtensibleSequence2",
@@ -1558,7 +1555,7 @@
 	.tag2el = asn_MAP_SimpleChoice_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_SimpleChoice = {
 	"SimpleChoice",
diff --git a/tests/tests-asn1c-compiler/72-same-names-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/72-same-names-OK.asn1.-Pfwide-types
index 1140af1..7f53a51 100644
--- a/tests/tests-asn1c-compiler/72-same-names-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/72-same-names-OK.asn1.-Pfwide-types
@@ -66,8 +66,7 @@
 	.tag2el = asn_MAP_Member_tag2el_2,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_Member_2 = {
@@ -199,8 +198,7 @@
 	.tag2el = asn_MAP_another_name_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_another_name_3 = {
@@ -241,7 +239,7 @@
 	.tag2el = asn_MAP_one_name_tag2el_2,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_one_name_2 = {
@@ -281,8 +279,7 @@
 	.tag2el = asn_MAP_Type1_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Type1 = {
 	"Type1",
@@ -475,8 +472,7 @@
 	.tag2el = asn_MAP_another_name_tag2el_3,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_another_name_3 = {
@@ -518,8 +514,7 @@
 	.tag2el = asn_MAP_one_name_tag2el_2,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_one_name_2 = {
@@ -571,8 +566,7 @@
 	.tag2el = asn_MAP_another_name_tag2el_8,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_another_name_8 = {
@@ -672,7 +666,7 @@
 	.tag2el = asn_MAP_Type2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Type2 = {
 	"Type2",
diff --git a/tests/tests-asn1c-compiler/73-circular-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/73-circular-OK.asn1.-Pfwide-types
index f297904..592e869 100644
--- a/tests/tests-asn1c-compiler/73-circular-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/73-circular-OK.asn1.-Pfwide-types
@@ -94,8 +94,7 @@
 	.tag2el = asn_MAP_Type_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Type = {
 	"Type",
@@ -281,8 +280,7 @@
 	.tag2el = asn_MAP_Epyt_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Epyt = {
 	"Epyt",
diff --git a/tests/tests-asn1c-compiler/84-param-tags-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/84-param-tags-OK.asn1.-Pfwide-types
index 6d9bba7..d4e4aa7 100644
--- a/tests/tests-asn1c-compiler/84-param-tags-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/84-param-tags-OK.asn1.-Pfwide-types
@@ -105,8 +105,7 @@
 	.tag2el = asn_MAP_TestType_16P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_TestType_16P0 = {
 	"TestType",
@@ -170,8 +169,7 @@
 	.tag2el = asn_MAP_TestType_16P1_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_TestType_16P1 = {
 	"TestType",
@@ -254,7 +252,7 @@
 	.tag2el = asn_MAP_TestChoice_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_TestChoice = {
 	"TestChoice",
@@ -379,8 +377,7 @@
 	.tag2el = asn_MAP_AutoType_34P0_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_AutoType_34P0 = {
 	"AutoType",
@@ -421,8 +418,7 @@
 	.tag2el = asn_MAP_AutoType_34P1_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_AutoType_34P1 = {
 	"AutoType",
@@ -505,7 +501,7 @@
 	.tag2el = asn_MAP_AutoChoice_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_AutoChoice = {
 	"AutoChoice",
diff --git a/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfcompound-names b/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfcompound-names
index 5b01772..bce1e67 100644
--- a/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfcompound-names
+++ b/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfcompound-names
@@ -55,7 +55,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfwide-types
index 5e99804..b239e7f 100644
--- a/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/89-bit-string-enum-OK.asn1.-Pfwide-types
@@ -55,7 +55,7 @@
 	.tag2el = asn_MAP_T_tag2el_1,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_T = {
 	"T",
diff --git a/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfindirect-choice b/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfindirect-choice
index 4ab6ef1..f417380 100644
--- a/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfindirect-choice
+++ b/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfindirect-choice
@@ -161,8 +161,7 @@
 	.tag2el = asn_MAP_Everything_tag2el_1,
 	.tag2el_count = 10,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Everything = {
 	"Everything",
@@ -259,7 +258,7 @@
 	.tag2el = asn_MAP_Choice1_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice1 = {
 	"Choice1",
@@ -356,7 +355,7 @@
 	.tag2el = asn_MAP_Choice2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice2 = {
 	"Choice2",
@@ -455,8 +454,7 @@
 	.tag2el = asn_MAP_a_tag2el_2,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_a_2 = {
@@ -554,7 +552,7 @@
 	.tag2el = asn_MAP_Choice3_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice3 = {
 	"Choice3",
@@ -685,8 +683,7 @@
 	.tag2el = asn_MAP_Member_tag2el_2,
 	.tag2el_count = 5,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	3,	/* Start extensions */
-	6	/* Stop extensions */
+	4,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_Member_2 = {
@@ -833,8 +830,7 @@
 	.tag2el = asn_MAP_Sequence_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	5	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
@@ -960,8 +956,7 @@
 	.tag2el = asn_MAP_b_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_b_3 = {
@@ -1013,8 +1008,7 @@
 	.tag2el = asn_MAP_Alpha_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Alpha = {
 	"Alpha",
@@ -1098,8 +1092,7 @@
 	.tag2el = asn_MAP_Beta_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Beta = {
 	"Beta",
@@ -1196,8 +1189,7 @@
 	.tag2el = asn_MAP_Gamma_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Gamma = {
 	"Gamma",
diff --git a/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfwide-types
index 85e4e63..dafb176 100644
--- a/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/92-circular-loops-OK.asn1.-Pfwide-types
@@ -161,8 +161,7 @@
 	.tag2el = asn_MAP_Everything_tag2el_1,
 	.tag2el_count = 10,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Everything = {
 	"Everything",
@@ -259,7 +258,7 @@
 	.tag2el = asn_MAP_Choice1_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice1 = {
 	"Choice1",
@@ -355,7 +354,7 @@
 	.tag2el = asn_MAP_Choice2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 1	/* Extensions start */
+	.first_extension = 1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice2 = {
 	"Choice2",
@@ -454,8 +453,7 @@
 	.tag2el = asn_MAP_a_tag2el_2,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_a_2 = {
@@ -553,7 +551,7 @@
 	.tag2el = asn_MAP_Choice3_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice3 = {
 	"Choice3",
@@ -684,8 +682,7 @@
 	.tag2el = asn_MAP_Member_tag2el_2,
 	.tag2el_count = 5,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	3,	/* Start extensions */
-	6	/* Stop extensions */
+	4,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_Member_2 = {
@@ -832,8 +829,7 @@
 	.tag2el = asn_MAP_Sequence_tag2el_1,
 	.tag2el_count = 4,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	1,	/* Start extensions */
-	5	/* Stop extensions */
+	2,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
@@ -959,8 +955,7 @@
 	.tag2el = asn_MAP_b_tag2el_3,
 	.tag2el_count = 1,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_b_3 = {
@@ -1012,8 +1007,7 @@
 	.tag2el = asn_MAP_Alpha_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Alpha = {
 	"Alpha",
@@ -1097,8 +1091,7 @@
 	.tag2el = asn_MAP_Beta_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Beta = {
 	"Beta",
@@ -1195,8 +1188,7 @@
 	.tag2el = asn_MAP_Gamma_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Gamma = {
 	"Gamma",
diff --git a/tests/tests-asn1c-compiler/93-asn1c-controls-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/93-asn1c-controls-OK.asn1.-Pfwide-types
index 25b381d..f02a3aa 100644
--- a/tests/tests-asn1c-compiler/93-asn1c-controls-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/93-asn1c-controls-OK.asn1.-Pfwide-types
@@ -55,8 +55,7 @@
 	.tag2el = asn_MAP_Sequence_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Sequence = {
 	"Sequence",
@@ -307,7 +306,7 @@
 	.tag2el = asn_MAP_Choice_tag2el_1,
 	.tag2el_count = 3,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice = {
 	"Choice",
diff --git a/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pfwide-types b/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pfwide-types
index 5cdf71e..c5682cd 100644
--- a/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pfwide-types
+++ b/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pfwide-types
@@ -90,7 +90,7 @@
 	.tag2el = asn_MAP_ch_tag2el_4,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_ch_4 = {
@@ -160,7 +160,7 @@
 	.tag2el = asn_MAP_Choice_tag2el_1,
 	.tag2el_count = 5,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = 3	/* Extensions start */
+	.first_extension = 3	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice = {
 	"Choice",
@@ -242,7 +242,7 @@
 	.tag2el = asn_MAP_Choice2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice2 = {
 	"Choice2",
diff --git a/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pgen-PER b/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pgen-PER
index 8c759dc..ae45367 100644
--- a/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pgen-PER
+++ b/tests/tests-asn1c-compiler/95-choice-per-order-OK.asn1.-Pgen-PER
@@ -106,7 +106,7 @@
 	.tag2el_count = 2,	/* Count of tags in the map */
 	.to_canonical_order = asn_MAP_ch_to_canonical_4,
 	.from_canonical_order = asn_MAP_ch_from_canonical_4,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 static /* Use -fall-defs-global to expose */
 asn_TYPE_descriptor_t asn_DEF_ch_4 = {
@@ -179,7 +179,7 @@
 	.tag2el_count = 5,	/* Count of tags in the map */
 	.to_canonical_order = asn_MAP_Choice_to_canonical_1,
 	.from_canonical_order = asn_MAP_Choice_from_canonical_1,
-	.ext_start = 3	/* Extensions start */
+	.first_extension = 3	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice = {
 	"Choice",
@@ -269,7 +269,7 @@
 	.tag2el = asn_MAP_Choice2_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0,
-	.ext_start = -1	/* Extensions start */
+	.first_extension = -1	/* Extensions start */
 };
 asn_TYPE_descriptor_t asn_DEF_Choice2 = {
 	"Choice2",
diff --git a/tests/tests-asn1c-compiler/98-attribute-class-OK.asn1.-P b/tests/tests-asn1c-compiler/98-attribute-class-OK.asn1.-P
index 589b80e..6f2ef86 100644
--- a/tests/tests-asn1c-compiler/98-attribute-class-OK.asn1.-P
+++ b/tests/tests-asn1c-compiler/98-attribute-class-OK.asn1.-P
@@ -89,8 +89,7 @@
 	.tag2el = asn_MAP_Attribute_tag2el_1,
 	.tag2el_count = 2,	/* Count of tags in the map */
 	0, 0, 0,	/* Optional elements (not needed) */
-	-1,	/* Start extensions */
-	-1	/* Stop extensions */
+	-1,	/* First extension addition */
 };
 asn_TYPE_descriptor_t asn_DEF_Attribute = {
 	"Attribute",