Move: Fix warning on companion used as implicit dispatch receiver

Do not report conflict if target class is a sublcass of
companion object's containing class

core/descriptors/src/org/jetbrains/kotlin/resolve/DescriptorUtils.kt

@@ -405,4 +405,6 @@ fun DeclarationDescriptor.isPublishedApi(): Boolean {
 fun DeclarationDescriptor.isAncestorOf(descriptor: DeclarationDescriptor, strict: Boolean): Boolean
         = DescriptorUtils.isAncestor(this, descriptor, strict)
 
-fun DeclarationDescriptor.isCompanionObject(): Boolean = DescriptorUtils.isCompanionObject(this)
+fun DeclarationDescriptor.isCompanionObject(): Boolean = DescriptorUtils.isCompanionObject(this)
+
+fun ClassDescriptor.isSubclassOf(superclass: ClassDescriptor): Boolean = DescriptorUtils.isSubclass(this, superclass)

idea/src/org/jetbrains/kotlin/idea/refactoring/move/moveDeclarations/MoveDeclarationsDelegate.kt

@@ -31,6 +31,7 @@ import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.containingClassOrObject
+import org.jetbrains.kotlin.resolve.descriptorUtil.isSubclassOf
 
 sealed class MoveDeclarationsDelegate {
     abstract fun getContainerChangeInfo(originalDeclaration: KtNamedDeclaration, moveTarget: KotlinMoveTarget): ContainerChangeInfo
@@ -82,6 +83,23 @@ sealed class MoveDeclarationsDelegate {
             return collectOuterInstanceReferences(classToMove)
         }
 
+        private fun isValidTargetForImplicitCompanionAsDispatchReceiver(
+                moveDescriptor: MoveDeclarationsDescriptor,
+                companionDescriptor: ClassDescriptor
+        ): Boolean {
+            val moveTarget = moveDescriptor.moveTarget
+            return when (moveTarget) {
+                is KotlinMoveTargetForCompanion -> true
+                is KotlinMoveTargetForExistingElement -> {
+                    val targetClass = moveTarget.targetElement as? KtClassOrObject ?: return false
+                    val targetClassDescriptor = targetClass.resolveToDescriptor() as ClassDescriptor
+                    val companionClassDescriptor = companionDescriptor.containingDeclaration as? ClassDescriptor ?: return false
+                    targetClassDescriptor.isSubclassOf(companionClassDescriptor)
+                }
+                else -> false
+            }
+        }
+
         override fun collectConflicts(
                 descriptor: MoveDeclarationsDescriptor,
                 internalUsages: MutableSet<UsageInfo>,
@@ -94,7 +112,7 @@ sealed class MoveDeclarationsDelegate {
 
                 val isConflict = when (usage) {
                     is ImplicitCompanionAsDispatchReceiverUsageInfo -> {
-                        if (descriptor.moveTarget !is KotlinMoveTargetForCompanion) {
+                        if (!isValidTargetForImplicitCompanionAsDispatchReceiver(descriptor, usage.companionDescriptor)) {
                             conflicts.putValue(element, "Implicit companion object will be inaccessible: ${element.text}")
                         }
                         true

idea/src/org/jetbrains/kotlin/idea/refactoring/move/moveUtils.kt

@@ -129,7 +129,7 @@ fun KtElement.processInternalReferencesToUpdateOnPackageNameChange(
                     val dispatchReceiver = refExpr.getResolvedCall(bindingContext)?.dispatchReceiver
                     val implicitClass = (dispatchReceiver as? ImplicitClassReceiver)?.classDescriptor
                     if (implicitClass?.isCompanionObject ?: false) {
-                        return ::ImplicitCompanionAsDispatchReceiverUsageInfo
+                        return { ImplicitCompanionAsDispatchReceiverUsageInfo(it, implicitClass!!) }
                     }
                     if (dispatchReceiver != null || containingDescriptor.kind != ClassKind.OBJECT) return null
                 }
@@ -178,7 +178,10 @@ fun KtElement.processInternalReferencesToUpdateOnPackageNameChange(
     }
 }
 
-class ImplicitCompanionAsDispatchReceiverUsageInfo(callee: KtSimpleNameExpression) : UsageInfo(callee)
+class ImplicitCompanionAsDispatchReceiverUsageInfo(
+        callee: KtSimpleNameExpression,
+        val companionDescriptor: ClassDescriptor
+) : UsageInfo(callee)
 
 interface KotlinMoveUsage {
     val isInternal: Boolean

idea/testData/refactoring/move/kotlin/moveNestedClass/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver/after/test.kt

@@ -0,0 +1,19 @@
+package test
+
+open class A {
+    companion object {
+        fun Int.extFoo(n: Int) {}
+
+        val Int.extBar: Int get() = 1
+    }
+
+}
+
+class C : A() {
+    class B {
+        fun test() {
+            1.extFoo(1.extBar)
+        }
+    }
+
+}

idea/testData/refactoring/move/kotlin/moveNestedClass/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver/before/test.kt

@@ -0,0 +1,19 @@
+package test
+
+open class A {
+    companion object {
+        fun Int.extFoo(n: Int) {}
+
+        val Int.extBar: Int get() = 1
+    }
+
+    class <caret>B {
+        fun test() {
+            1.extFoo(1.extBar)
+        }
+    }
+}
+
+class C : A() {
+
+}

idea/testData/refactoring/move/kotlin/moveNestedClass/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver.test

@@ -0,0 +1,6 @@
+{
+  "mainFile": "test.kt",
+  "type": "MOVE_KOTLIN_NESTED_CLASS",
+  "targetClass": "test.C",
+  "withRuntime": "true"
+}

idea/tests/org/jetbrains/kotlin/idea/refactoring/move/MoveTestGenerated.java

@@ -372,6 +372,12 @@ public class MoveTestGenerated extends AbstractMoveTest {
         doTest(fileName);
     }
 
+    @TestMetadata("kotlin/moveNestedClass/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver.test")
+    public void testKotlin_moveNestedClass_nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver_NonInnerToSubclassWithCompanionAsImplicitDispatchReceiver() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/move/kotlin/moveNestedClass/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver/nonInnerToSubclassWithCompanionAsImplicitDispatchReceiver.test");
+        doTest(fileName);
+    }
+
     @TestMetadata("kotlin/moveNestedClass/nonInnerToTopLevel/nonInnerToTopLevel.test")
     public void testKotlin_moveNestedClass_nonInnerToTopLevel_NonInnerToTopLevel() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/refactoring/move/kotlin/moveNestedClass/nonInnerToTopLevel/nonInnerToTopLevel.test");