[K/N] Implement new class initialization order.

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersBlocksAndObject.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM, JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM, JVM_IR
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersEnumImplementingInterfaceWithDefaultMember.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM_IR
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersInheritance.kt

@@ -1,5 +1,4 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: NATIVE
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersInheritanceMixedWithObject.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM, JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM, JVM_IR
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersInheritanceMultiLevel.kt

@@ -1,5 +1,4 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: NATIVE
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersInheritanceMultipleSupertypes.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM_IR
 
 var initOrder = ""
 

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersInheritanceMultipleSupertypesMixedOrder.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM_IR
 
 // This test is essentially the same one as initializersInheritanceMultipleSupertypes,
 // but with different super type kinds order (interface, class, interface)
@@ -59,11 +59,11 @@ fun box(): String {
     if (Foo.fooProp2 != "foo2") return "FAIL: fooProp2=${Foo.fooProp2}"
 
     // Order: superclass, then superinterfaces (declaration order), then Foo itself.
-    if (initOrder != "IF2 BAR1 BAR2 IF1 FOO1 FOO2 ") return "FAIL: initOrder=$initOrder"
+    if (initOrder != "BAR1 BAR2 IF2 IF1 FOO1 FOO2 ") return "FAIL: initOrder=$initOrder"
 
     // Accessing companion members again must not re-run any initializer.
     if (Foo.fooProp2 != "foo2") return "FAIL: fooProp2 (second access)=${Foo.fooProp2}"
-    if (initOrder != "IF2 BAR1 BAR2 IF1 FOO1 FOO2 ") return "FAIL: initOrder after re-access=$initOrder"
+    if (initOrder != "BAR1 BAR2 IF2 IF1 FOO1 FOO2 ") return "FAIL: initOrder after re-access=$initOrder"
 
     return "OK"
 }

compiler/testData/codegen/box/companionBlocksAndExtensions/initializersTriggeredByObject.kt

@@ -1,5 +1,5 @@
 // LANGUAGE: +CompanionBlocksAndExtensions
-// IGNORE_BACKEND: JVM, JVM_IR, NATIVE
+// IGNORE_BACKEND: JVM, JVM_IR
 
 var initOrder = ""
 

compiler/testData/codegen/box/objects/companionObjectAccess/companionInitOrderWithSuperclassCrossModule.kt

@@ -1,5 +1,7 @@
 // ISSUE: KT-86521 Native: init order of companion objects is different from JVM
 // IGNORE_BACKEND: NATIVE
+// ^ On Native `CompanionBlocksAndExtensions` language feature enables the JVM-like initialization.
+//   See nativeCompanionInitOrderCrossModule* tests for Native-specific treatment.
 // ISSUE: KT-84267 K/Wasm: init order of companion objects is different from JVM
 // ISSUE: KT-86640 K/Wasm: cross-module signature mismatch for parent companion getInstance
 // IGNORE_KLIB_RUNTIME_ERRORS_WITH_CUSTOM_SECOND_STAGE: Wasm-js:2.3,2.4

compiler/testData/codegen/box/objects/companionObjectAccess/companionObjectInitOrderWithSuperclass.kt

@@ -1,5 +1,7 @@
 // ISSUE: KT-86521 Native: init order of companion objects is different from JVM
 // IGNORE_BACKEND: NATIVE
+// ^ On Native `CompanionBlocksAndExtensions` language feature enables the JVM-like initialization.
+//   See nativeCompanionInitOrder* tests for Native-specific treatment.
 // ISSUE: KT-84267 K/Wasm: init order of companion objects is different from JVM
 // IGNORE_KLIB_RUNTIME_ERRORS_WITH_CUSTOM_SECOND_STAGE: Wasm-js:2.3,2.4
 // ^^^KT-84267 is fixed in 2.4.20-beta1
@@ -189,6 +191,62 @@ class A16 : B16<String>() {
     companion object { init { log("A16.Companion") } }
 }
 
+// multiple interface inheritance
+interface I17 {
+    fun i() {}
+    companion object { init { log("I17.Companion") } }
+}
+interface J17 {
+    fun j() {}
+    companion object { init { log("J17.Companion") } }
+}
+interface K17 : I17 {
+    fun k() {}
+    companion object { init { log("K17.Companion") } }
+}
+interface L17 : J17 {
+    fun l() {}
+    companion object { init { log("L17.Companion") } }
+}
+interface M17 {
+    companion object { init { log("M17.Companion") } }
+}
+open class B17 : J17, K17 {
+    companion object { init { log("B17.Companion") } }
+}
+class A17: B17(), L17, M17 {
+    companion object { init { log("A17.Companion") } }
+}
+
+// multiple interface inheritance; with instance creation
+interface I18 {
+    fun i() {}
+    companion object { init { log("I18.Companion") } }
+}
+interface J18 {
+    fun j() {}
+    companion object { init { log("J18.Companion") } }
+}
+interface K18 : I18 {
+    fun k() {}
+    companion object { init { log("K18.Companion") } }
+}
+interface L18 : J18 {
+    fun l() {}
+    companion object { init { log("L18.Companion") } }
+}
+interface M18 {
+    companion object { init { log("M18.Companion") } }
+}
+open class B18 : J18, K18 {
+    init { log("B18.init") }
+    companion object { init { log("B18.Companion") } }
+}
+class A18: B18(), L18, M18 {
+    init { log("A18.init") }
+    companion object { init { log("A18.Companion") } }
+}
+
 fun box(): String {
     l = ""
     A1
@@ -279,5 +337,15 @@ fun box(): String {
     val r16 = l
     if (r16 != "B16.Companion\nA16.Companion\n") return "fail test16: '$r16'"
 
+    l = ""
+    A17
+    val r17 = l
+    if (r17 != "J17.Companion\nI17.Companion\nK17.Companion\nB17.Companion\nL17.Companion\nA17.Companion\n") return "fail test17: '$r17'"
+
+    l = ""
+    A18()
+    val r18 = l
+    if (r18 != "J18.Companion\nI18.Companion\nK18.Companion\nB18.Companion\nL18.Companion\nA18.Companion\nB18.init\nA18.init\n") return "fail test18: '$r18'"
+
     return "OK"
 }