Support delegating to interfaces in ultra-light classes

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/ultraLightPsi.kt

@@ -18,9 +18,11 @@ import org.jetbrains.kotlin.asJava.builder.LightClassData
 import org.jetbrains.kotlin.asJava.elements.KtLightDeclaration
 import org.jetbrains.kotlin.asJava.elements.KtLightField
 import org.jetbrains.kotlin.asJava.elements.KtLightMethod
+import org.jetbrains.kotlin.backend.common.CodegenUtil
 import org.jetbrains.kotlin.backend.common.DataClassMethodGenerator
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
 import org.jetbrains.kotlin.codegen.JvmCodegenUtil
+import org.jetbrains.kotlin.codegen.kotlinType
 import org.jetbrains.kotlin.codegen.state.KotlinTypeMapper
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.descriptors.annotations.Annotated
@@ -33,6 +35,7 @@ import org.jetbrains.kotlin.name.SpecialNames
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.containingClass
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.DelegationResolver
 import org.jetbrains.kotlin.resolve.DescriptorToSourceUtils
 import org.jetbrains.kotlin.resolve.DescriptorUtils
 import org.jetbrains.kotlin.resolve.annotations.JVM_STATIC_ANNOTATION_FQ_NAME
@@ -293,6 +296,7 @@ open class KtUltraLightClass(classOrObject: KtClassOrObject, internal val suppor
         }
 
         addMethodsFromDataClass(result)
+        addDelegatesToInterfaceMethods(result)
 
         result
     }
@@ -332,6 +336,28 @@ open class KtUltraLightClass(classOrObject: KtClassOrObject, internal val suppor
         }.generate()
     }
 
+    private fun addDelegatesToInterfaceMethods(result: MutableList<KtLightMethod>) {
+        classOrObject.superTypeListEntries.filterIsInstance<KtDelegatedSuperTypeEntry>().forEach {
+            addDelegatesToInterfaceMethods(it, result)
+        }
+    }
+
+    private fun addDelegatesToInterfaceMethods(superTypeEntry: KtDelegatedSuperTypeEntry, result: MutableList<KtLightMethod>) {
+        val classDescriptor = classOrObject.resolve() as? ClassDescriptor ?: return
+        val typeReference = superTypeEntry.typeReference ?: return
+        val bindingContext = typeReference.analyze()
+
+        val superClassDescriptor = CodegenUtil.getSuperClassBySuperTypeListEntry(superTypeEntry, bindingContext) ?: return
+        val delegationType = superTypeEntry.delegateExpression.kotlinType(bindingContext) ?: return
+
+        for (delegate in DelegationResolver.getDelegates(classDescriptor, superClassDescriptor, delegationType).keys) {
+            when (delegate) {
+                is PropertyDescriptor -> delegate.accessors.mapTo(result, this::createGeneratedMethodFromDescriptor)
+                is FunctionDescriptor -> result.add(createGeneratedMethodFromDescriptor(delegate))
+            }
+        }
+    }
+
     private fun createConstructors(): List<KtLightMethod> {
         val result = arrayListOf<KtLightMethod>()
         val constructors = classOrObject.allConstructors

compiler/light-classes/src/org/jetbrains/kotlin/asJava/classes/ultraLightUtils.kt

@@ -29,6 +29,7 @@ import org.jetbrains.kotlin.config.JvmTarget
 import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.load.kotlin.TypeMappingMode
 import org.jetbrains.kotlin.psi.KtDeclaration
+import org.jetbrains.kotlin.psi.KtElement
 import org.jetbrains.kotlin.psi.KtTypeParameter
 import org.jetbrains.kotlin.psi.KtTypeParameterListOwner
 import org.jetbrains.kotlin.resolve.BindingContext
@@ -130,7 +131,7 @@ internal fun KtDeclaration.getKotlinType(): KotlinType? {
 }
 
 internal fun KtDeclaration.resolve() = LightClassGenerationSupport.getInstance(project).resolveToDescriptor(this)
-internal fun KtDeclaration.analyze() = LightClassGenerationSupport.getInstance(project).analyze(this)
+internal fun KtElement.analyze() = LightClassGenerationSupport.getInstance(project).analyze(this)
 
 // copy-pasted from kotlinInternalUastUtils.kt and post-processed
 internal fun KotlinType.asPsiType(
@@ -233,7 +234,7 @@ fun KtUltraLightClass.createGeneratedMethodFromDescriptor(
 private fun KtUltraLightClass.lightMethod(
     descriptor: FunctionDescriptor
 ): LightMethodBuilder {
-    val name = descriptor.name.asString()
+    val name = typeMapper(support).mapFunctionName(descriptor, OwnerKind.IMPLEMENTATION)
 
     val accessFlags: Int by lazyPub {
         val asmFlags = AsmUtil.getMethodAsmFlags(descriptor, OwnerKind.IMPLEMENTATION, support.deprecationResolver)

compiler/testData/asJava/ultraLightClasses/delegatingToInterfaces.kt

@@ -2,6 +2,11 @@
 interface Base {
     fun printMessage()
     fun printMessageLine()
+
+    val x: Int
+    var y: Int
+
+    fun String.foo(y: Any?): Int
 }
 
 class BaseImpl(val x: Int) : Base {
@@ -9,7 +14,6 @@ class BaseImpl(val x: Int) : Base {
     override fun printMessageLine() { println(x) }
 }
 
-/** should load cls */
 class Derived(b: Base) : Base by b {
     override fun printMessage() { print("abc") }
 }

idea/idea-analysis/src/org/jetbrains/kotlin/idea/caches/resolve/IDELightClassGenerationSupport.kt

@@ -122,8 +122,6 @@ class IDELightClassGenerationSupport(private val project: Project) : LightClassG
 
 
         if (declaration is KtClassOrObject) {
-            declaration.superTypeListEntries.find { it is KtDelegatedSuperTypeEntry }?.let { return it }
-
             declaration.primaryConstructor?.let { findTooComplexDeclaration(it) }?.let { return it }
 
             for (d in declaration.declarations) {