Properly handle extensions to inlined classes when producing framework

See https://github.com/JetBrains/kotlin-native/issues/2120#issuecomment-424262886

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/objcexport/ObjCExportMapper.kt

@@ -11,12 +11,10 @@ import org.jetbrains.kotlin.backend.konan.*
 import org.jetbrains.kotlin.backend.konan.descriptors.allOverriddenDescriptors
 import org.jetbrains.kotlin.backend.konan.descriptors.isArray
 import org.jetbrains.kotlin.backend.konan.descriptors.isInterface
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.builtins.PrimitiveType
 import org.jetbrains.kotlin.builtins.UnsignedType
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.name.ClassId
-import org.jetbrains.kotlin.name.FqNameUnsafe
 import org.jetbrains.kotlin.resolve.descriptorUtil.*
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
@@ -34,18 +32,17 @@ internal abstract class ObjCExportMapper {
     }
 }
 
-private fun ObjCExportMapper.isRepresentedAsObjCInterface(descriptor: ClassDescriptor): Boolean =
-        !descriptor.isInterface && !isSpecialMapped(descriptor)
-
 internal fun ObjCExportMapper.getClassIfCategory(descriptor: CallableMemberDescriptor): ClassDescriptor? {
     if (descriptor.dispatchReceiverParameter != null) return null
 
     val extensionReceiverType = descriptor.extensionReceiverParameter?.type ?: return null
 
+    // FIXME: this code must rely on type mapping instead of copying its logic.
+
     if (extensionReceiverType.isObjCObjectType()) return null
 
     val erasedClass = extensionReceiverType.getErasedTypeClass()
-    return if (this.isRepresentedAsObjCInterface(erasedClass)) {
+    return if (!erasedClass.isInterface && !erasedClass.isInlined() && !this.isSpecialMapped(erasedClass)) {
         erasedClass
     } else {
         // E.g. receiver is protocol, or some type with custom mapping.

backend.native/tests/framework/values/values.kt

@@ -132,6 +132,9 @@ fun Any?.toString(): String = this?.toString() ?: "null"
 
 fun Any?.print() = println(this.toString())
 
+fun Char.boxChar(): Char? = this
+fun Char?.isA(): Boolean = (this == 'A')
+
 // Lambdas
 val sumLambda = { x: Int, y: Int -> x + y }
 
@@ -224,3 +227,12 @@ fun box(ic3: IC3): Any = ic3
 
 fun concatenateInlineClassValues(ic1: IC1, ic1N: IC1?, ic2: IC2, ic2N: IC2?, ic3: IC3, ic3N: IC3?): String =
         "${ic1.value} ${ic1N?.value} ${ic2.value} ${ic2N?.value} ${ic3.value} ${ic3N?.value}"
+
+fun IC1.getValue1() = this.value
+fun IC1?.getValueOrNull1() = this?.value
+
+fun IC2.getValue2() = value
+fun IC2?.getValueOrNull2() = this?.value
+
+fun IC3.getValue3() = value
+fun IC3?.getValueOrNull3() = this?.value

backend.native/tests/framework/values/values.swift

@@ -314,6 +314,11 @@ func testAnyPrint() throws {
     print("END")
 }
 
+func testCharExtensions() throws {
+    try assertTrue(ValuesKt.isA(ValuesKt.boxChar(65)))
+    try assertFalse(ValuesKt.isA(ValuesKt.boxChar(66)))
+}
+
 func testLambda() throws {
     try assertEquals(actual: ValuesKt.sumLambda(3, 4), expected: 7)
 }
@@ -404,6 +409,15 @@ func testInlineClasses() throws {
         actual: ValuesKt.concatenateInlineClassValues(ic1: ic1, ic1N: nil, ic2: ic2, ic2N: nil, ic3: nil, ic3N: nil),
         expected: "42 null foo null null null"
     )
+
+    try assertEquals(actual: ValuesKt.getValue1(ic1), expected: 42)
+    try assertEquals(actual: ValuesKt.getValueOrNull1(ic1N) as! Int, expected: 17)
+
+    try assertEquals(actual: ValuesKt.getValue2(ic2), expected: "foo")
+    try assertEquals(actual: ValuesKt.getValueOrNull2(ic2N), expected: "bar")
+
+    try assertEquals(actual: ValuesKt.getValue3(ic3), expected: ic3)
+    try assertEquals(actual: ValuesKt.getValueOrNull3(ic3N), expected: nil)
 }
 
 // -------- Execution of the test --------
@@ -431,6 +445,7 @@ class ValuesTests : TestProvider {
             TestCase(name: "TestStringExtension", method: withAutorelease(testStrExtFun)),
             TestCase(name: "TestAnyToString", method: withAutorelease(testAnyToString)),
             TestCase(name: "TestAnyPrint", method: withAutorelease(testAnyPrint)),
+            TestCase(name: "TestCharExtensions", method: withAutorelease(testCharExtensions)),
             TestCase(name: "TestLambda", method: withAutorelease(testLambda)),
             TestCase(name: "TestInterfaceExtension", method: withAutorelease(testInterfaceExtension)),
             TestCase(name: "TestClassInstances", method: withAutorelease(testClassInstances)),