Supported KProperty2 and KMutableProperty2 for delegated properties

Consider this code:
object Delegate {
    operator fun getValue(t: Any?, p: KProperty<*>): String {
        return ""
    }
}

class A {
    val String.ext by Delegate
}

then the type of <p> is KProperty2 (it has 2 receivers).

Test fix + review fixes

compiler/frontend/src/org/jetbrains/kotlin/types/expressions/DoubleColonExpressionResolver.kt

@@ -772,7 +772,7 @@ class DoubleColonExpressionResolver(
                         val setter = descriptor.setter
                         setter == null || Visibilities.isVisible(receiverType?.let(::TransientReceiver), setter, scopeOwnerDescriptor)
                     }
-                    reflectionTypes.getKPropertyType(Annotations.EMPTY, receiverType, descriptor.type, mutable)
+                    reflectionTypes.getKPropertyType(Annotations.EMPTY, listOfNotNull(receiverType), descriptor.type, mutable)
                 }
                 is VariableDescriptor -> null
                 else -> throw UnsupportedOperationException("Callable reference resolved to an unsupported descriptor: $descriptor")

compiler/ir/ir.psi2ir/src/org/jetbrains/kotlin/psi2ir/generators/DelegatedPropertyGenerator.kt

@@ -80,9 +80,8 @@ class DelegatedPropertyGenerator(override val context: GeneratorContext) : Gener
     }
 
     private fun getKPropertyTypeForDelegatedProperty(propertyDescriptor: PropertyDescriptor): KotlinType {
-        val propertyReceiverType = propertyDescriptor.extensionReceiverParameter?.type ?:
-                                   propertyDescriptor.dispatchReceiverParameter?.type
-        return context.reflectionTypes.getKPropertyType(Annotations.EMPTY, propertyReceiverType, propertyDescriptor.type, propertyDescriptor.isVar)
+        val receivers = listOfNotNull(propertyDescriptor.extensionReceiverParameter, propertyDescriptor.dispatchReceiverParameter)
+        return context.reflectionTypes.getKPropertyType(Annotations.EMPTY, receivers.map{ it.type }, propertyDescriptor.type, propertyDescriptor.isVar)
     }
 
     private fun generateDelegateFieldForProperty(
@@ -195,7 +194,7 @@ class DelegatedPropertyGenerator(override val context: GeneratorContext) : Gener
     }
 
     private fun getKPropertyTypeForLocalDelegatedProperty(variableDescriptor: VariableDescriptorWithAccessors) =
-            context.reflectionTypes.getKPropertyType(Annotations.EMPTY, null, variableDescriptor.type, variableDescriptor.isVar)
+            context.reflectionTypes.getKPropertyType(Annotations.EMPTY, emptyList(), variableDescriptor.type, variableDescriptor.isVar)
 
     private fun createPropertyDelegateDescriptor(
             propertyDescriptor: PropertyDescriptor,

compiler/testData/ir/irText/declarations/provideDelegate/memberExtension.txt

@@ -37,7 +37,7 @@ FILE /memberExtension.kt
             $this: GET_VAR '<receiver: Host>' type=Host origin=null
             $receiver: CONST String type=kotlin.String value='K'
             host: GET_VAR '<receiver: Host>' type=Host origin=null
-            p: CALLABLE_REFERENCE 'plusK: String on String' type=kotlin.reflect.KProperty1<kotlin.String, kotlin.String> origin=PROPERTY_REFERENCE_FOR_DELEGATE
+            p: CALLABLE_REFERENCE 'plusK: String on String' type=kotlin.reflect.KProperty2<kotlin.String, Host, kotlin.String> origin=PROPERTY_REFERENCE_FOR_DELEGATE
       FUN DELEGATED_PROPERTY_ACCESSOR public final fun kotlin.String.<get-plusK>(): kotlin.String
         BLOCK_BODY
           RETURN type=kotlin.Nothing from='<get-plusK>() on String: String'
@@ -45,7 +45,7 @@ FILE /memberExtension.kt
               $this: GET_FIELD '`plusK$delegate`: Host.StringDelegate' type=Host.StringDelegate origin=null
                 receiver: GET_VAR '<receiver: Host>' type=Host origin=null
               receiver: GET_VAR '<receiver: plusK: String on String>' type=kotlin.String origin=null
-              p: CALLABLE_REFERENCE 'plusK: String on String' type=kotlin.reflect.KProperty1<kotlin.String, kotlin.String> origin=PROPERTY_REFERENCE_FOR_DELEGATE
+              p: CALLABLE_REFERENCE 'plusK: String on String' type=kotlin.reflect.KProperty2<kotlin.String, Host, kotlin.String> origin=PROPERTY_REFERENCE_FOR_DELEGATE
     PROPERTY public final val ok: kotlin.String
       FIELD PROPERTY_BACKING_FIELD public final val ok: kotlin.String
         EXPRESSION_BODY

core/descriptors/src/org/jetbrains/kotlin/builtins/ReflectionTypes.kt

@@ -60,6 +60,7 @@ class ReflectionTypes(module: ModuleDescriptor, private val notFoundClasses: Not
     val kProperty2: ClassDescriptor by ClassLookup(3)
     val kMutableProperty0: ClassDescriptor by ClassLookup(1)
     val kMutableProperty1: ClassDescriptor by ClassLookup(2)
+    val kMutableProperty2: ClassDescriptor by ClassLookup(3)
 
     fun getKClassType(annotations: Annotations, type: KotlinType, variance: Variance): KotlinType =
             KotlinTypeFactory.simpleNotNullType(annotations, kClass, listOf(TypeProjectionImpl(variance, type)))
@@ -77,23 +78,24 @@ class ReflectionTypes(module: ModuleDescriptor, private val notFoundClasses: Not
         return KotlinTypeFactory.simpleNotNullType(annotations, classDescriptor, arguments)
     }
 
-    fun getKPropertyType(annotations: Annotations, receiverType: KotlinType?, returnType: KotlinType, mutable: Boolean): KotlinType {
-        val classDescriptor = when {
-            receiverType != null -> when {
-                mutable -> kMutableProperty1
-                else -> kProperty1
-            }
-            else -> when {
+    fun getKPropertyType(annotations: Annotations, receiverTypes: List<KotlinType>, returnType: KotlinType, mutable: Boolean): KotlinType {
+        val classDescriptor = when (receiverTypes.size) {
+            0 -> when {
                 mutable -> kMutableProperty0
                 else -> kProperty0
             }
+            1 -> when {
+                mutable -> kMutableProperty1
+                else -> kProperty1
+            }
+            2 ->  when {
+                mutable -> kMutableProperty2
+                else -> kProperty2
+            }
+            else -> throw AssertionError("More than 2 receivers is not allowed")
         }
 
-        val arguments = ArrayList<TypeProjection>(2)
-        if (receiverType != null) {
-            arguments.add(TypeProjectionImpl(receiverType))
-        }
-        arguments.add(TypeProjectionImpl(returnType))
+        val arguments = (receiverTypes + returnType).map(::TypeProjectionImpl)
         return KotlinTypeFactory.simpleNotNullType(annotations, classDescriptor, arguments)
     }