KT-7883 Receiver parameter falsely marked as unused

#KT-7883 fixed

idea/ide-common/src/org/jetbrains/kotlin/idea/util/extensionsUtils.kt

@@ -17,13 +17,17 @@
 package org.jetbrains.kotlin.idea.util
 
 import org.jetbrains.kotlin.descriptors.CallableDescriptor
-import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
+import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
+import org.jetbrains.kotlin.psi.JetPsiUtil
+import org.jetbrains.kotlin.psi.JetThisExpression
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
-import org.jetbrains.kotlin.resolve.scopes.JetScope
-import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.resolve.calls.smartcasts.SmartCastUtils
-import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
+import org.jetbrains.kotlin.resolve.scopes.JetScope
+import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
+import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
+import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
 
 public enum class CallType {
     NORMAL,
@@ -102,3 +106,15 @@ public fun CallableDescriptor.substituteExtensionIfCallable(
     }
 }
 
+public fun ReceiverValue.getThisReceiverOwner(bindingContext: BindingContext): DeclarationDescriptor? {
+    return when (this) {
+        is ExpressionReceiver -> {
+            val thisRef = (JetPsiUtil.deparenthesize(this.getExpression()) as? JetThisExpression)?.getInstanceReference() ?: return null
+            bindingContext[BindingContext.REFERENCE_TARGET, thisRef]
+        }
+
+        is ThisReceiver -> this.getDeclarationDescriptor()
+
+        else -> null
+    }
+}

idea/src/org/jetbrains/kotlin/idea/highlighter/KotlinRecursiveCallLineMarkerProvider.kt

@@ -27,6 +27,7 @@ import com.intellij.psi.PsiElement
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
+import org.jetbrains.kotlin.idea.util.getThisReceiverOwner
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.parents
 import org.jetbrains.kotlin.resolve.BindingContext
@@ -77,17 +78,9 @@ public class KotlinRecursiveCallLineMarkerProvider() : LineMarkerProvider {
         if (resolvedCall.getCandidateDescriptor().getOriginal() != enclosingFunctionDescriptor) return false
 
         fun isDifferentReceiver(receiver: ReceiverValue): Boolean {
-            val receiverOwner =
-                    when (receiver) {
-                        is ExpressionReceiver -> {
-                            val thisRef = (JetPsiUtil.deparenthesize(receiver.getExpression()) as?
-                                    JetThisExpression)?.getInstanceReference() ?: return true
-                            bindingContext[BindingContext.REFERENCE_TARGET, thisRef] ?: return true
-                        }
+            if (receiver == ReceiverValue.NO_RECEIVER) return false
 
-                        is ThisReceiver -> receiver.getDeclarationDescriptor()
-                        else -> return false
-                    }
+            val receiverOwner = receiver.getThisReceiverOwner(bindingContext) ?: return true
 
             return when (receiverOwner) {
                 is SimpleFunctionDescriptor -> receiverOwner != enclosingFunctionDescriptor

idea/src/org/jetbrains/kotlin/idea/inspections/UnusedReceiverParameterInspection.kt

@@ -19,16 +19,23 @@ package org.jetbrains.kotlin.idea.inspections
 import com.intellij.codeInspection.*
 import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiElementVisitor
+import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.ReceiverParameterDescriptor
+import org.jetbrains.kotlin.descriptors.SimpleFunctionDescriptor
 import org.jetbrains.kotlin.idea.JetBundle
 import org.jetbrains.kotlin.idea.caches.resolve.analyze
 import org.jetbrains.kotlin.idea.search.usagesSearch.descriptor
+import org.jetbrains.kotlin.idea.util.getThisReceiverOwner
 import org.jetbrains.kotlin.lexer.JetTokens
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.isOverridable
 import org.jetbrains.kotlin.psi.typeRefHelpers.setReceiverTypeReference
+import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.calls.callUtil.getResolvedCall
+import org.jetbrains.kotlin.resolve.scopes.receivers.ExpressionReceiver
 import org.jetbrains.kotlin.resolve.scopes.receivers.ExtensionReceiver
+import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
+import org.jetbrains.kotlin.resolve.scopes.receivers.ThisReceiver
 import kotlin.properties.Delegates
 
 public class UnusedReceiverParameterInspection : AbstractKotlinInspection() {
@@ -52,10 +59,9 @@ public class UnusedReceiverParameterInspection : AbstractKotlinInspection() {
 
                         val bindingContext = element.analyze()
                         val resolvedCall = element.getResolvedCall(bindingContext) ?: return
-                        if ((resolvedCall.getDispatchReceiver() as? ExtensionReceiver)?.getDeclarationDescriptor() == callable) {
-                            used = true
-                        }
-                        else if (((resolvedCall.getExtensionReceiver() as? ExtensionReceiver)?.getDeclarationDescriptor() == callable)) {
+
+                        if (resolvedCall.getDispatchReceiver().getThisReceiverOwner(bindingContext) == callable ||
+                            resolvedCall.getExtensionReceiver().getThisReceiverOwner(bindingContext) == callable) {
                             used = true
                         }
                         else if ((resolvedCall.getCandidateDescriptor() as? ReceiverParameterDescriptor)?.getContainingDeclaration() == callable) {

idea/testData/inspections/unusedReceiverParameter/invokeConvention.kt

@@ -0,0 +1,5 @@
+// KT-7883 Receiver parameter falsely marked as unused
+
+fun (() -> Any).foo() {
+    this()
+}