Support default arguments for expected declarations

#KT-21913 Fixed

compiler/testData/codegen/box/multiplatform/defaultArguments/constructor.kt

@@ -0,0 +1,21 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// FILE: common.kt
+
+expect class Foo(a: String, b: Int = 0, c: Double? = null)
+
+// FILE: jvm.kt
+
+import kotlin.test.assertEquals
+
+actual class Foo actual constructor(a: String, b: Int, c: Double?) {
+    val result: String = a + "," + b + "," + c
+}
+
+fun box(): String {
+    assertEquals("OK,0,null", Foo("OK").result)
+    assertEquals("OK,42,null", Foo("OK", 42).result)
+    assertEquals("OK,42,3.14", Foo("OK", 42, 3.14).result)
+
+    return "OK"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/function.kt

@@ -0,0 +1,32 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// FILE: common.kt
+
+expect fun topLevel(a: String, b: Int = 0, c: Double? = null): String
+
+expect class Foo() {
+    fun member(a: String, b: Int = 0, c: Double? = null): String
+}
+
+// FILE: jvm.kt
+
+import kotlin.test.assertEquals
+
+actual fun topLevel(a: String, b: Int, c: Double?): String = a + "," + b + "," + c
+
+actual class Foo actual constructor() {
+    actual fun member(a: String, b: Int, c: Double?): String = a + "," + b + "," + c
+}
+
+fun box(): String {
+    assertEquals("OK,0,null", topLevel("OK"))
+    assertEquals("OK,42,null", topLevel("OK", 42))
+    assertEquals("OK,42,3.14", topLevel("OK", 42, 3.14))
+
+    val foo = Foo()
+    assertEquals("OK,0,null", foo.member("OK"))
+    assertEquals("OK,42,null", foo.member("OK", 42))
+    assertEquals("OK,42,3.14", foo.member("OK", 42, 3.14))
+
+    return "OK"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromCommonClass.kt

@@ -0,0 +1,24 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// FILE: common.kt
+
+open class A() {
+    fun member(a: String, b: Int = 0, c: Double? = null): String = a + "," + b + "," + c
+}
+
+expect class B() : A
+
+// FILE: jvm.kt
+
+import kotlin.test.assertEquals
+
+actual class B actual constructor() : A()
+
+fun box(): String {
+    val b = B()
+    assertEquals("OK,0,null", b.member("OK"))
+    assertEquals("OK,42,null", b.member("OK", 42))
+    assertEquals("OK,42,3.14", b.member("OK", 42, 3.14))
+
+    return "OK"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/inheritedFromExpectedClass.kt

@@ -0,0 +1,28 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// FILE: common.kt
+
+expect open class A() {
+    fun member(a: String, b: Int = 0, c: Double? = null): String
+}
+
+expect class B() : A
+
+// FILE: jvm.kt
+
+import kotlin.test.assertEquals
+
+actual open class A actual constructor() {
+    actual fun member(a: String, b: Int, c: Double?): String = a + "," + b + "," + c
+}
+
+actual class B actual constructor() : A()
+
+fun box(): String {
+    val b = B()
+    assertEquals("OK,0,null", b.member("OK"))
+    assertEquals("OK,42,null", b.member("OK", 42))
+    assertEquals("OK,42,3.14", b.member("OK", 42, 3.14))
+
+    return "OK"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/inlineFunctionWithDefaultLambda.kt

@@ -0,0 +1,32 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// FILE: common.kt
+
+expect inline fun topLevel(a: String, b: Int = 0, c: () -> Double? = { null }): String
+
+expect class Foo() {
+    inline fun member(a: String, b: Int = 0, c: () -> Double? = { null }): String
+}
+
+// FILE: jvm.kt
+
+import kotlin.test.assertEquals
+
+actual inline fun topLevel(a: String, b: Int, c: () -> Double?): String = a + "," + b + "," + c()
+
+actual class Foo actual constructor() {
+    actual inline fun member(a: String, b: Int, c: () -> Double?): String = a + "," + b + "," + c()
+}
+
+fun box(): String {
+    assertEquals("OK,0,null", topLevel("OK"))
+    assertEquals("OK,42,null", topLevel("OK", 42))
+    assertEquals("OK,42,3.14", topLevel("OK", 42, { 3.14 }))
+
+    val foo = Foo()
+    assertEquals("OK,0,null", foo.member("OK"))
+    assertEquals("OK,42,null", foo.member("OK", 42))
+    assertEquals("OK,42,3.14", foo.member("OK", 42, { 3.14 }))
+
+    return "OK"
+}