From 1bca314f04dd012a1af5bb315ed600f6cc8639eb Mon Sep 17 00:00:00 2001
From: Toshiaki Kameyama <kmymtsak@gmail.com>
Date: Wed, 29 Jun 2022 13:42:13 +0900
Subject: [PATCH] [kotlin] Fix false positive "Receiver parameter is never
 used" with reified type parameter

^KTIJ-10490 Fixed

closes https://github.com/JetBrains/intellij-community/pull/2070

GitOrigin-RevId: bc7a3937ced466edeba8331e8fbb10743a68c48d
---
 .../inspections/UnusedReceiverParameterInspection.kt   |  9 +++++++++
 .../idea/inspections/LocalInspectionTestGenerated.java | 10 ++++++++++
 .../unusedReceiverParameter/reified.kt                 |  5 +++++
 .../unusedReceiverParameter/reified.kt.after           |  5 +++++
 .../unusedReceiverParameter/reifiedWithClassLiteral.kt |  7 +++++++
 5 files changed, 36 insertions(+)
 create mode 100644 plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt
 create mode 100644 plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt.after
 create mode 100644 plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reifiedWithClassLiteral.kt

diff --git a/plugins/kotlin/idea/src/org/jetbrains/kotlin/idea/inspections/UnusedReceiverParameterInspection.kt b/plugins/kotlin/idea/src/org/jetbrains/kotlin/idea/inspections/UnusedReceiverParameterInspection.kt
index 65442ada3a89..83b6fbd60f09 100644
--- a/plugins/kotlin/idea/src/org/jetbrains/kotlin/idea/inspections/UnusedReceiverParameterInspection.kt
+++ b/plugins/kotlin/idea/src/org/jetbrains/kotlin/idea/inspections/UnusedReceiverParameterInspection.kt
@@ -25,6 +25,7 @@ import org.jetbrains.kotlin.idea.refactoring.changeSignature.modify
 import org.jetbrains.kotlin.idea.refactoring.changeSignature.runChangeSignature
 import org.jetbrains.kotlin.idea.refactoring.explicateAsTextForReceiver
 import org.jetbrains.kotlin.idea.refactoring.getThisLabelName
+import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
 import org.jetbrains.kotlin.idea.util.getThisReceiverOwner
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -40,6 +41,7 @@ import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.resolve.calls.model.VariableAsFunctionResolvedCall
 import org.jetbrains.kotlin.resolve.calls.util.getResolvedCall
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
+import org.jetbrains.kotlin.utils.addToStdlib.safeAs
 
 class UnusedReceiverParameterInspection : AbstractKotlinInspection(), CleanupLocalInspectionTool {
     override fun buildVisitor(holder: ProblemsHolder, isOnTheFly: Boolean, session: LocalInspectionToolSession): PsiElementVisitor {
@@ -183,6 +185,13 @@ fun isUsageOfDescriptor(descriptor: DeclarationDescriptor, element: KtElement, c
     }
 
     if (element !is KtExpression) return false
+
+    if (element is KtClassLiteralExpression) {
+        val typeParameter = element.receiverExpression?.mainReference?.resolve() as? KtTypeParameter
+        val typeParameterDescriptor = context[BindingContext.TYPE_PARAMETER, typeParameter]
+        if (descriptor.safeAs<CallableDescriptor>()?.typeParameters?.any { it == typeParameterDescriptor } == true) return true
+    }
+
     return when (element) {
         is KtDestructuringDeclarationEntry -> {
             listOf { context[BindingContext.COMPONENT_RESOLVED_CALL, element] }
diff --git a/plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java b/plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
index 7f4973a3fd32..1f43f811eaf4 100644
--- a/plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
+++ b/plugins/kotlin/idea/tests/test/org/jetbrains/kotlin/idea/inspections/LocalInspectionTestGenerated.java
@@ -15954,6 +15954,16 @@ public abstract class LocalInspectionTestGenerated extends AbstractLocalInspecti
         public void testPropertyWithTypeParameterInClass2() throws Exception {
             runTest("testData/inspectionsLocal/unusedReceiverParameter/propertyWithTypeParameterInClass2.kt");
         }
+
+        @TestMetadata("reified.kt")
+        public void testReified() throws Exception {
+            runTest("testData/inspectionsLocal/unusedReceiverParameter/reified.kt");
+        }
+
+        @TestMetadata("reifiedWithClassLiteral.kt")
+        public void testReifiedWithClassLiteral() throws Exception {
+            runTest("testData/inspectionsLocal/unusedReceiverParameter/reifiedWithClassLiteral.kt");
+        }
     }
 
     @RunWith(JUnit3RunnerWithInners.class)
diff --git a/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt
new file mode 100644
index 000000000000..b4af40d283ff
--- /dev/null
+++ b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt
@@ -0,0 +1,5 @@
+inline fun <reified T> <caret>T.testFun(t: T): String = t.toString()
+
+fun main() {
+    5.testFun(5)
+}
diff --git a/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt.after b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt.after
new file mode 100644
index 000000000000..65bc1fa11a60
--- /dev/null
+++ b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reified.kt.after
@@ -0,0 +1,5 @@
+inline fun <reified T> testFun(t: T): String = t.toString()
+
+fun main() {
+    testFun(5)
+}
\ No newline at end of file
diff --git a/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reifiedWithClassLiteral.kt b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reifiedWithClassLiteral.kt
new file mode 100644
index 000000000000..59af9a796ef9
--- /dev/null
+++ b/plugins/kotlin/idea/tests/testData/inspectionsLocal/unusedReceiverParameter/reifiedWithClassLiteral.kt
@@ -0,0 +1,7 @@
+// PROBLEM: none
+// WITH_STDLIB
+inline fun <reified T> <caret>T.testFun(): String = (T::class.java).name
+
+fun main() {
+    5.testFun()
+}
\ No newline at end of file