Added test to check default params in declaration (issue KT-23239)

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

@@ -0,0 +1,30 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// IGNORE_BACKEND: JVM_IR
+// FILE: common.kt
+
+expect open class C() {
+    open fun f(p: Int = 2) : String
+}
+
+// FILE: platform.kt
+
+import kotlin.test.assertEquals
+
+actual open class C {
+    actual open fun f(p: Int) = "C" + p
+}
+
+open class D : C() {
+    override open fun f(p: Int) = "D" + p
+}
+
+fun box(): String {
+
+    assertEquals("C2", C().f())
+    assertEquals("C9", C().f(9))
+    assertEquals("D2", D().f())
+    assertEquals("D5", D().f(5))
+
+    return "OK"
+}

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

@@ -0,0 +1,34 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// IGNORE_BACKEND: JVM_IR
+// FILE: common.kt
+
+expect open class A() {
+    open fun f(p: Int = 1) : String
+}
+
+expect open class B : A {
+    override open fun f(p: Int) : String
+}
+
+// FILE: platform.kt
+
+import kotlin.test.assertEquals
+
+actual open class A {
+    actual open fun f(p: Int) = "A" + p
+}
+
+actual open class B : A() {
+    actual override open fun f(p: Int) = "B" + p
+}
+
+fun box(): String {
+
+    assertEquals("A1", A().f())
+    assertEquals("A9", A().f(9))
+    assertEquals("B1", B().f())
+    assertEquals("B5", B().f(5))
+
+    return "OK"
+}

compiler/testData/codegen/box/multiplatform/defaultArguments/kt23239.kt

@@ -0,0 +1,34 @@
+// !LANGUAGE: +MultiPlatformProjects
+// WITH_RUNTIME
+// IGNORE_BACKEND: JVM_IR
+// FILE: common.kt
+
+expect open class C() {
+    open fun f(p: Int = 1) : String
+    open fun f2(p1: Int = 1, p2: Int = 2) : String
+    open fun ff(p1: Int, p2: Int = 2) : String
+    open fun fff(p1: Int, p2: Int, p3: Int = 3) : String
+    open fun fffx(p1: Int, p2: Int = 4, p3: Int = 5) : String
+}
+// FILE: platform.kt
+
+import kotlin.test.assertEquals
+
+actual open class C {
+    actual open fun f(p: Int) =  "f" + p
+    actual open fun f2(p1: Int, p2: Int) = "f2" + p1 + "" + p2
+    actual open fun ff(p1: Int, p2: Int) = "ff" + p1 + "" + p2
+    actual open fun fff(p1: Int, p2: Int, p3: Int) = "fff" + p1 + "" + p2 + "" + p3
+    actual open fun fffx(p1: Int, p2: Int, p3: Int) = "fffx" + p1 + "" + p2 + "" + p3
+}
+
+fun box(): String {
+
+    assertEquals("f1", C().f())
+    assertEquals("f212", C().f2())
+    assertEquals("ff12", C().ff(1))
+    assertEquals("fff123", C().fff(1, 2))
+    assertEquals("fffx345", C().fffx(3))
+
+    return "OK"
+}