Generate equals/hashCode(): Use class literals when possible

#KT-18683 Fixed

idea/src/org/jetbrains/kotlin/idea/actions/generate/KotlinGenerateEqualsAndHashcodeAction.kt

@@ -24,6 +24,7 @@ import com.intellij.openapi.project.Project
 import com.intellij.psi.PsiNameIdentifierOwner
 import com.intellij.util.IncorrectOperationException
 import org.jetbrains.kotlin.builtins.KotlinBuiltIns
+import org.jetbrains.kotlin.config.LanguageFeature
 import org.jetbrains.kotlin.descriptors.ClassDescriptor
 import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.VariableDescriptor
@@ -34,11 +35,15 @@ import org.jetbrains.kotlin.idea.core.CollectingNameValidator
 import org.jetbrains.kotlin.idea.core.KotlinNameSuggester
 import org.jetbrains.kotlin.idea.core.insertMembersAfter
 import org.jetbrains.kotlin.idea.core.quoteIfNeeded
+import org.jetbrains.kotlin.idea.project.languageVersionSettings
+import org.jetbrains.kotlin.idea.project.platform
 import org.jetbrains.kotlin.idea.util.IdeDescriptorRenderers
 import org.jetbrains.kotlin.idea.util.application.runWriteAction
+import org.jetbrains.kotlin.js.resolve.JsPlatform
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.getElementTextWithContext
 import org.jetbrains.kotlin.resolve.BindingContext
+import org.jetbrains.kotlin.resolve.TargetPlatform
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
 import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
 import org.jetbrains.kotlin.resolve.lazy.BodyResolveMode
@@ -134,7 +139,27 @@ class KotlinGenerateEqualsAndHashcodeAction : KotlinGenerateMemberActionBase<Kot
         }
     }
 
-    private fun generateEquals(project: Project, info: Info): KtNamedFunction? {
+    private fun generateClassLiteralsNotEqual(paramName: String, targetClass: KtClassOrObject): String {
+        val defaultExpression = "$paramName?.javaClass != javaClass"
+        if (!targetClass.languageVersionSettings.supportsFeature(LanguageFeature.BoundCallableReferences)) return defaultExpression
+        return when (targetClass.platform) {
+            is JsPlatform -> "other == null || $paramName::class.js != this::class.js"
+            is TargetPlatform.Default -> "other == null || $paramName::class != this::class"
+            else -> defaultExpression
+        }
+    }
+
+    private fun generateClassLiteral(targetClass: KtClassOrObject): String {
+        val defaultExpression = "javaClass"
+        if (!targetClass.languageVersionSettings.supportsFeature(LanguageFeature.BoundCallableReferences)) return defaultExpression
+        return when (targetClass.platform) {
+            is JsPlatform -> "this::class.js"
+            is TargetPlatform.Default -> "this::class"
+            else -> defaultExpression
+        }
+    }
+
+    private fun generateEquals(project: Project, info: Info, targetClass: KtClassOrObject): KtNamedFunction? {
         with(info) {
             if (!needEquals) return null
 
@@ -149,7 +174,12 @@ class KotlinGenerateEqualsAndHashcodeAction : KotlinGenerateMemberActionBase<Kot
             }
 
             val useIsCheck = CodeInsightSettings.getInstance().USE_INSTANCEOF_ON_EQUALS_PARAMETER
-            val isNotInstanceCondition = if (useIsCheck) "$paramName !is $typeForCast" else "$paramName?.javaClass != javaClass"
+            val isNotInstanceCondition = if (useIsCheck) {
+                "$paramName !is $typeForCast"
+            }
+            else {
+                generateClassLiteralsNotEqual(paramName, targetClass)
+            }
             val bodyText = StringBuilder().apply {
                 append("if (this === $paramName) return true\n")
                 append("if ($isNotInstanceCondition) return false\n")
@@ -189,7 +219,7 @@ class KotlinGenerateEqualsAndHashcodeAction : KotlinGenerateMemberActionBase<Kot
         }
     }
 
-    private fun generateHashCode(project: Project, info: Info): KtNamedFunction? {
+    private fun generateHashCode(project: Project, info: Info, targetClass: KtClassOrObject): KtNamedFunction? {
         fun VariableDescriptor.genVariableHashCode(parenthesesNeeded: Boolean): String {
             val ref = (DescriptorToSourceUtilsIde.getAnyDeclaration(project, this) as PsiNameIdentifierOwner).nameIdentifier!!.text
             val isNullable = TypeUtils.isNullableType(type)
@@ -226,7 +256,7 @@ class KotlinGenerateEqualsAndHashcodeAction : KotlinGenerateMemberActionBase<Kot
             val initialValue = when {
                 !builtins.isMemberOfAny(superHashCode) -> "super.hashCode()"
                 propertyIterator.hasNext() -> propertyIterator.next().genVariableHashCode(false)
-                else -> "javaClass.hashCode()"
+                else -> generateClassLiteral(targetClass) + ".hashCode()"
             }
 
             val bodyText = if (propertyIterator.hasNext()) {
@@ -249,8 +279,8 @@ class KotlinGenerateEqualsAndHashcodeAction : KotlinGenerateMemberActionBase<Kot
         val targetClass = info.classDescriptor.source.getPsi() as KtClass
         val prototypes = ArrayList<KtDeclaration>(2)
                 .apply {
-                    addIfNotNull(generateEquals(project, info))
+                    addIfNotNull(generateEquals(project, info, targetClass))
-                    addIfNotNull(generateHashCode(project, info))
+                    addIfNotNull(generateHashCode(project, info, targetClass))
                 }
         val anchor = with(targetClass.declarations) { lastIsInstanceOrNull<KtNamedFunction>() ?: lastOrNull() }
         return insertMembersAfter(editor, targetClass, prototypes, anchor)

idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsCommon.kt

@@ -0,0 +1,8 @@
+// PLATFORM: Common
+class A(val n: Int, val s: String) {<caret>
+    val f: Float = 1.0f
+
+    fun foo() {
+
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsCommon.kt.after

@@ -0,0 +1,28 @@
+// PLATFORM: Common
+class A(val n: Int, val s: String) {
+    val f: Float = 1.0f
+
+    fun foo() {
+
+    }
+
+    <caret>override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || other::class != this::class) return false
+
+        other as A
+
+        if (n != other.n) return false
+        if (s != other.s) return false
+        if (f != other.f) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = n
+        result = 31 * result + s.hashCode()
+        result = 31 * result + f.hashCode()
+        return result
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsJS.kt

@@ -0,0 +1,8 @@
+// PLATFORM: JavaScript
+class A(val n: Int, val s: String) {<caret>
+    val f: Float = 1.0f
+
+    fun foo() {
+
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsJS.kt.after

@@ -0,0 +1,28 @@
+// PLATFORM: JavaScript
+class A(val n: Int, val s: String) {
+    val f: Float = 1.0f
+
+    fun foo() {
+
+    }
+
+    <caret>override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || other::class.js != this::class.js) return false
+
+        other as A
+
+        if (n != other.n) return false
+        if (s != other.s) return false
+        if (f != other.f) return false
+
+        return true
+    }
+
+    override fun hashCode(): Int {
+        var result = n
+        result = 31 * result + s.hashCode()
+        result = 31 * result + f.hashCode()
+        return result
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/noVarsCommon.kt

@@ -0,0 +1,6 @@
+// PLATFORM: Common
+class A {<caret>
+    fun foo() {
+
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/noVarsCommon.kt.after

@@ -0,0 +1,16 @@
+// PLATFORM: Common
+class A {
+    fun foo() {
+
+    }
+
+    <caret>override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || other::class != this::class) return false
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return this::class.hashCode()
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/noVarsJS.kt

@@ -0,0 +1,6 @@
+// PLATFORM: JavaScript
+class A {<caret>
+    fun foo() {
+
+    }
+}

idea/testData/codeInsight/generate/equalsWithHashCode/noVarsJS.kt.after

@@ -0,0 +1,16 @@
+// PLATFORM: JavaScript
+class A {
+    fun foo() {
+
+    }
+
+    <caret>override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other == null || other::class.js != this::class.js) return false
+        return true
+    }
+
+    override fun hashCode(): Int {
+        return this::class.js.hashCode()
+    }
+}

idea/tests/org/jetbrains/kotlin/idea/codeInsight/generate/AbstractCodeInsightActionTest.kt

@@ -28,6 +28,11 @@ import junit.framework.TestCase
 import org.jetbrains.kotlin.idea.test.ConfigLibraryUtil
 import org.jetbrains.kotlin.idea.test.KotlinLightCodeInsightFixtureTestCase
 import org.jetbrains.kotlin.idea.test.KotlinWithJdkAndRuntimeLightProjectDescriptor
+import org.jetbrains.kotlin.js.resolve.JsPlatform
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.targetPlatform
+import org.jetbrains.kotlin.resolve.TargetPlatform
+import org.jetbrains.kotlin.resolve.jvm.platform.JvmPlatform
 import org.jetbrains.kotlin.test.InTextDirectivesUtils
 import org.jetbrains.kotlin.test.KotlinTestUtils
 import java.io.File
@@ -61,6 +66,8 @@ abstract class AbstractCodeInsightActionTest : KotlinLightCodeInsightFixtureTest
         val conflictFile = File("$path.messages")
         val afterFile = File("$path.after")
 
+        var mainPsiFile: KtFile? = null
+
         try {
             ConfigLibraryUtil.configureLibrariesByDirective(myModule, PlatformTestUtil.getCommunityPath(), fileText)
 
@@ -76,7 +83,18 @@ abstract class AbstractCodeInsightActionTest : KotlinLightCodeInsightFixtureTest
                         myFixture.configureByFile(File(rootDir, it).path.replace(File.separator, "/"))
                     }
             configureExtra(path, fileText)
-            myFixture.configureByFile(path)
+            mainPsiFile = myFixture.configureByFile(path) as KtFile
+
+            val targetPlatformName = InTextDirectivesUtils.findStringWithPrefixes(fileText, "// PLATFORM: ")
+            if (targetPlatformName != null) {
+                val targetPlatform = when (targetPlatformName) {
+                    "JVM" -> JvmPlatform
+                    "JavaScript" -> JsPlatform
+                    "Common" -> TargetPlatform.Default
+                    else -> error("Unexpected platform name: $targetPlatformName")
+                }
+                mainPsiFile.targetPlatform = targetPlatform
+            }
 
             val action = createAction(fileText)
 
@@ -103,6 +121,7 @@ abstract class AbstractCodeInsightActionTest : KotlinLightCodeInsightFixtureTest
             KotlinTestUtils.assertEqualsToFile(conflictFile, e.message!!)
         }
         finally {
+            mainPsiFile?.targetPlatform = null
             ConfigLibraryUtil.unconfigureLibrariesByDirective(myModule, fileText)
         }
     }

idea/tests/org/jetbrains/kotlin/idea/codeInsight/generate/GenerateHashCodeAndEqualsActionTestGenerated.java

@@ -108,6 +108,18 @@ public class GenerateHashCodeAndEqualsActionTestGenerated extends AbstractGenera
         doTest(fileName);
     }
 
+    @TestMetadata("multipleVarsCommon.kt")
+    public void testMultipleVarsCommon() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsCommon.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("multipleVarsJS.kt")
+    public void testMultipleVarsJS() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsJS.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("multipleVarsNullable.kt")
     public void testMultipleVarsNullable() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/multipleVarsNullable.kt");
@@ -132,6 +144,18 @@ public class GenerateHashCodeAndEqualsActionTestGenerated extends AbstractGenera
         doTest(fileName);
     }
 
+    @TestMetadata("noVarsCommon.kt")
+    public void testNoVarsCommon() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/noVarsCommon.kt");
+        doTest(fileName);
+    }
+
+    @TestMetadata("noVarsJS.kt")
+    public void testNoVarsJS() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/noVarsJS.kt");
+        doTest(fileName);
+    }
+
     @TestMetadata("noVarsWithSuperClass.kt")
     public void testNoVarsWithSuperClass() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("idea/testData/codeInsight/generate/equalsWithHashCode/noVarsWithSuperClass.kt");