Fix some bugs appeared in 610c9b52

* Property references in top-level initializers
* Empty String constructor
* Special case when inheriting multiple method implementations
* Getting IR for error types

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/descriptors/DescriptorUtils.kt

@@ -48,14 +48,42 @@ internal val ClassDescriptor.implementedInterfaces: List<ClassDescriptor>
  *
  * TODO: this method is actually a part of resolve and probably duplicates another one
  */
-internal tailrec fun IrSimpleFunction.resolveFakeOverride(): IrSimpleFunction {
+internal fun IrSimpleFunction.resolveFakeOverride(): IrSimpleFunction {
     if (this.isReal) {
         return this
-    } else {
-        return overriddenSymbols
-                .firstOrNull { it.owner.modality != Modality.ABSTRACT }!!
-                .owner.resolveFakeOverride()
     }
+
+    val visited = mutableSetOf<IrSimpleFunction>()
+    val realSupers = mutableSetOf<IrSimpleFunction>()
+
+    fun findRealSupers(function: IrSimpleFunction) {
+        if (function in visited) return
+        visited += function
+        if (function.isReal) {
+            realSupers += function
+        } else {
+            function.overriddenSymbols.forEach { findRealSupers(it.owner) }
+        }
+    }
+
+    findRealSupers(this)
+
+    if (realSupers.size > 1) {
+        visited.clear()
+
+        fun excludeOverridden(function: IrSimpleFunction) {
+            if (function in visited) return
+            visited += function
+            function.overriddenSymbols.forEach {
+                realSupers.remove(it.owner)
+                excludeOverridden(it.owner)
+            }
+        }
+
+        realSupers.toList().forEach { excludeOverridden(it) }
+    }
+
+    return realSupers.first { it.modality != Modality.ABSTRACT }
 }
 
 private val intrinsicAnnotation = FqName("konan.internal.Intrinsic")

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/irasdescriptors/NewIrUtils.kt

@@ -37,6 +37,7 @@ import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.name.Name
 import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.serialization.deserialization.descriptors.DeserializedPropertyDescriptor
+import org.jetbrains.kotlin.types.ErrorUtils
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
 
@@ -178,7 +179,7 @@ fun IrModuleFragment.referenceAllTypeExternalClassifiers(symbolTable: SymbolTabl
 
     fun KotlinType.referenceAllClassifiers() {
         TypeUtils.getClassDescriptor(this)?.let {
-            if (it.module != moduleDescriptor) {
+            if (!ErrorUtils.isError(it) && it.module != moduleDescriptor) {
                 if (it.kind == ClassKind.ENUM_ENTRY) {
                     symbolTable.referenceEnumEntry(it)
                 } else {

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/llvm/IrToBitcode.kt

@@ -1990,7 +1990,7 @@ internal class CodeGeneratorVisitor(val context: Context, val lifetimes: Map<IrE
                 assert(args.isNotEmpty() && args[0].type == int32Type)
                 functionGenerationContext.allocArray(codegen.typeInfoValue(constructedClass), args[0],
                         resultLifetime(callee))
-            } else if (constructedClass == context.builtIns.string) {
+            } else if (constructedClass == context.ir.symbols.string.owner) {
                 // TODO: consider returning the empty string literal instead.
                 assert(args.isEmpty())
                 functionGenerationContext.allocArray(codegen.typeInfoValue(constructedClass), count = kImmZero,

backend.native/compiler/ir/backend.native/src/org/jetbrains/kotlin/backend/konan/lower/DelegationLowering.kt

@@ -190,10 +190,12 @@ internal class PropertyDelegationLowering(val context: KonanBackendContext) : Fi
         if (kProperties.isNotEmpty()) {
             val initializers = kProperties.values.sortedBy { it.second }.map { it.first }
             // TODO: move to object for lazy initialization.
-            irFile.addChild(kPropertiesField.apply {
+            irFile.declarations.add(0, kPropertiesField.apply {
                 initializer = IrExpressionBodyImpl(UNDEFINED_OFFSET, UNDEFINED_OFFSET,
                         context.createArrayOfExpression(kPropertyImplType, initializers, UNDEFINED_OFFSET, UNDEFINED_OFFSET))
             })
+
+            kPropertiesField.parent = irFile
         }
     }