Don't require to override abstract methods in expect class

#KT-16099 Fixed

compiler/frontend/src/org/jetbrains/kotlin/resolve/DeclarationsChecker.kt

@@ -32,7 +32,7 @@ import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.psi.psiUtil.hasActualModifier
 import org.jetbrains.kotlin.psi.psiUtil.visibilityModifier
 import org.jetbrains.kotlin.resolve.BindingContext.*
-import org.jetbrains.kotlin.resolve.DescriptorUtils.classCanHaveAbstractMembers
+import org.jetbrains.kotlin.resolve.DescriptorUtils.classCanHaveAbstractDeclaration
 import org.jetbrains.kotlin.resolve.DescriptorUtils.classCanHaveOpenMembers
 import org.jetbrains.kotlin.resolve.calls.results.TypeSpecificityComparator
 import org.jetbrains.kotlin.resolve.descriptorUtil.builtIns
@@ -585,7 +585,7 @@ class DeclarationsChecker(
         if (modifierList != null) {
             if (modifierList.hasModifier(KtTokens.ABSTRACT_KEYWORD)) {
                 //has abstract modifier
-                if (!classCanHaveAbstractMembers(classDescriptor)) {
+                if (!classCanHaveAbstractDeclaration(classDescriptor)) {
                     trace.report(ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS.on(property, property.name ?: "", classDescriptor))
                     return
                 }
@@ -705,7 +705,7 @@ class DeclarationsChecker(
         if (containingDescriptor is ClassDescriptor) {
             val inInterface = containingDescriptor.kind == ClassKind.INTERFACE
             val isExpectClass = containingDescriptor.isExpect
-            if (hasAbstractModifier && !classCanHaveAbstractMembers(containingDescriptor)) {
+            if (hasAbstractModifier && !classCanHaveAbstractDeclaration(containingDescriptor)) {
                 trace.report(ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS.on(function, functionDescriptor.name.asString(), containingDescriptor))
             }
             val hasBody = function.hasBody()

compiler/frontend/src/org/jetbrains/kotlin/resolve/OverrideResolver.kt

@@ -33,7 +33,7 @@ import org.jetbrains.kotlin.diagnostics.Errors.*
 import org.jetbrains.kotlin.incremental.components.NoLookupLocation
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.resolve.DescriptorUtils.classCanHaveAbstractMembers
+import org.jetbrains.kotlin.resolve.DescriptorUtils.classCanHaveAbstractFakeOverride
 import org.jetbrains.kotlin.resolve.OverridingUtil.OverrideCompatibilityInfo.Result.OVERRIDABLE
 import org.jetbrains.kotlin.resolve.calls.callResolverUtil.isOrOverridesSynthesized
 import org.jetbrains.kotlin.types.*
@@ -211,7 +211,7 @@ class OverrideResolver(
         }
 
         internal fun doReportErrors() {
-            val canHaveAbstractMembers = classCanHaveAbstractMembers(classDescriptor)
+            val canHaveAbstractMembers = classCanHaveAbstractFakeOverride(classDescriptor)
             if (abstractInBaseClassNoImpl.isNotEmpty() && !canHaveAbstractMembers) {
                 trace.report(ABSTRACT_CLASS_MEMBER_NOT_IMPLEMENTED.on(klass, klass, abstractInBaseClassNoImpl.first()))
             }

compiler/testData/diagnostics/tests/multiplatform/headerClass/dontOverrideMethodsFromInterfaceInCommonCode.kt

@@ -0,0 +1,28 @@
+// !LANGUAGE: +MultiPlatformProjects
+// MODULE: m1-common
+// FILE: common.kt
+
+interface Foo {
+    fun foo()
+}
+
+expect class ImplicitFoo : Foo
+
+expect class ExplicitFoo : Foo {
+    override fun foo()
+}
+
+expect class ImplicitFooCheck : Foo
+
+// MODULE: m2-jvm(m1-common)
+// FILE: jvm.kt
+
+actual class ImplicitFoo : Foo {
+    override fun foo() {}
+}
+
+actual class ExplicitFoo : Foo {
+    actual override fun foo() {}
+}
+
+actual <!ABSTRACT_MEMBER_NOT_IMPLEMENTED!>class ImplicitFooCheck<!> : Foo

compiler/testData/diagnostics/tests/multiplatform/headerClass/dontOverrideMethodsFromInterfaceInCommonCode.txt

@@ -0,0 +1,65 @@
+// -- Module: <m1-common> --
+package
+
+public final expect class ExplicitFoo : Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open expect override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class ImplicitFoo : Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class ImplicitFooCheck : Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+
+// -- Module: <m2-jvm> --
+package
+
+public final actual class ExplicitFoo : Foo {
+    public constructor ExplicitFoo()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open actual override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final actual class ImplicitFoo : Foo {
+    public constructor ImplicitFoo()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final actual class ImplicitFooCheck : Foo {
+    public constructor ImplicitFooCheck()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithExplicitAbstractMember.kt

@@ -0,0 +1,23 @@
+// !LANGUAGE: +MultiPlatformProjects
+// MODULE: m1-common
+// FILE: common.kt
+
+interface Foo {
+    fun foo()
+}
+
+expect class NonAbstractClass : Foo {
+    <!ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS!>abstract<!> fun bar()
+
+    <!ABSTRACT_PROPERTY_IN_NON_ABSTRACT_CLASS!>abstract<!> val baz: Int
+
+    <!ABSTRACT_FUNCTION_IN_NON_ABSTRACT_CLASS!>abstract<!> override fun foo()
+}
+
+expect abstract class AbstractClass : Foo {
+    abstract fun bar()
+
+    abstract val baz: Int
+
+    abstract override fun foo()
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithExplicitAbstractMember.txt

@@ -0,0 +1,26 @@
+package
+
+public abstract expect class AbstractClass : Foo {
+    public expect abstract val baz: kotlin.Int
+    public abstract expect fun bar(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public interface Foo {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class NonAbstractClass : Foo {
+    public expect abstract val baz: kotlin.Int
+    public abstract expect fun bar(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithoutExplicitOverrideOfMethod.kt

@@ -0,0 +1,36 @@
+// !LANGUAGE: +MultiPlatformProjects
+// MODULE: m1-common
+// FILE: common.kt
+
+expect abstract class Base {
+    abstract fun foo()
+}
+
+expect class DerivedImplicit : Base
+
+expect class DerivedExplicit : Base {
+    override fun foo()
+}
+
+expect class DerivedExplicitCheck : Base {
+    override fun foo()
+}
+
+// MODULE: m2-jvm(m1-common)
+// FILE: jvm.kt
+
+actual abstract class Base {
+    actual abstract fun foo()
+}
+
+actual class DerivedImplicit : Base() {
+    override fun foo() {}
+}
+
+actual class DerivedExplicit : Base() {
+    actual override fun foo() {}
+}
+
+actual class DerivedExplicitCheck : Base() {
+    override fun <!ACTUAL_MISSING!>foo<!>() {}
+}

compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithoutExplicitOverrideOfMethod.txt

@@ -0,0 +1,66 @@
+// -- Module: <m1-common> --
+package
+
+public abstract expect class Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class DerivedExplicit : Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open expect override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class DerivedExplicitCheck : Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open expect override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final expect class DerivedImplicit : Base {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract expect override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+
+// -- Module: <m2-jvm> --
+package
+
+public abstract actual class Base {
+    public constructor Base()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public abstract actual fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final actual class DerivedExplicit : Base {
+    public constructor DerivedExplicit()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open actual override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final actual class DerivedExplicitCheck : Base {
+    public constructor DerivedExplicitCheck()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final actual class DerivedImplicit : Base {
+    public constructor DerivedImplicit()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun foo(): kotlin.Unit
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}

compiler/testData/multiplatform/explicitActualOnOverrideOfAbstractMethod/common.kt

@@ -0,0 +1,5 @@
+expect abstract class Base {
+    abstract fun foo()
+}
+
+expect class DerivedImplicit : Base

compiler/testData/multiplatform/explicitActualOnOverrideOfAbstractMethod/jvm.kt

@@ -0,0 +1,7 @@
+actual abstract class Base {
+    actual abstract fun foo()
+}
+
+actual class DerivedImplicit : Base() {
+    override fun foo() {}
+}

compiler/testData/multiplatform/explicitActualOnOverrideOfAbstractMethod/output.txt

@@ -0,0 +1,7 @@
+-- Common --
+Exit code: OK
+Output:
+
+-- JVM --
+Exit code: OK
+Output:

compiler/tests/org/jetbrains/kotlin/checkers/DiagnosticsTestGenerated.java

@@ -14067,6 +14067,18 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("dontOverrideMethodsFromInterfaceInCommonCode.kt")
+                public void testDontOverrideMethodsFromInterfaceInCommonCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/dontOverrideMethodsFromInterfaceInCommonCode.kt");
+                    doTest(fileName);
+                }
+
+                @TestMetadata("expectClassWithExplicitAbstractMember.kt")
+                public void testExpectClassWithExplicitAbstractMember() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithExplicitAbstractMember.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("expectClassWithoutConstructor.kt")
                 public void testExpectClassWithoutConstructor() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithoutConstructor.kt");
@@ -14079,6 +14091,12 @@ public class DiagnosticsTestGenerated extends AbstractDiagnosticsTest {
                     doTest(fileName);
                 }
 
+                @TestMetadata("extendExpectedClassWithoutExplicitOverrideOfMethod.kt")
+                public void testExtendExpectedClassWithoutExplicitOverrideOfMethod() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithoutExplicitOverrideOfMethod.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("extraHeaderOnMembers.kt")
                 public void testExtraHeaderOnMembers() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt");

compiler/tests/org/jetbrains/kotlin/checkers/javac/DiagnosticsUsingJavacTestGenerated.java

@@ -14067,6 +14067,18 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                     doTest(fileName);
                 }
 
+                @TestMetadata("dontOverrideMethodsFromInterfaceInCommonCode.kt")
+                public void testDontOverrideMethodsFromInterfaceInCommonCode() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/dontOverrideMethodsFromInterfaceInCommonCode.kt");
+                    doTest(fileName);
+                }
+
+                @TestMetadata("expectClassWithExplicitAbstractMember.kt")
+                public void testExpectClassWithExplicitAbstractMember() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithExplicitAbstractMember.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("expectClassWithoutConstructor.kt")
                 public void testExpectClassWithoutConstructor() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/expectClassWithoutConstructor.kt");
@@ -14079,6 +14091,12 @@ public class DiagnosticsUsingJavacTestGenerated extends AbstractDiagnosticsUsing
                     doTest(fileName);
                 }
 
+                @TestMetadata("extendExpectedClassWithoutExplicitOverrideOfMethod.kt")
+                public void testExtendExpectedClassWithoutExplicitOverrideOfMethod() throws Exception {
+                    String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/extendExpectedClassWithoutExplicitOverrideOfMethod.kt");
+                    doTest(fileName);
+                }
+
                 @TestMetadata("extraHeaderOnMembers.kt")
                 public void testExtraHeaderOnMembers() throws Exception {
                     String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/multiplatform/headerClass/extraHeaderOnMembers.kt");

compiler/tests/org/jetbrains/kotlin/multiplatform/MultiPlatformIntegrationTestGenerated.java

@@ -54,6 +54,12 @@ public class MultiPlatformIntegrationTestGenerated extends AbstractMultiPlatform
         doTest(fileName);
     }
 
+    @TestMetadata("explicitActualOnOverrideOfAbstractMethod")
+    public void testExplicitActualOnOverrideOfAbstractMethod() throws Exception {
+        String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/multiplatform/explicitActualOnOverrideOfAbstractMethod/");
+        doTest(fileName);
+    }
+
     @TestMetadata("genericDeclarations")
     public void testGenericDeclarations() throws Exception {
         String fileName = KotlinTestUtils.navigationMetadata("compiler/testData/multiplatform/genericDeclarations/");

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

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
+ * Copyright 2010-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -458,7 +458,11 @@ public class DescriptorUtils {
                KotlinTypeChecker.DEFAULT.equalTypes(builtIns.getAnyType(), type);
     }
 
-    public static boolean classCanHaveAbstractMembers(@NotNull ClassDescriptor classDescriptor) {
+    public static boolean classCanHaveAbstractFakeOverride(@NotNull ClassDescriptor classDescriptor) {
+        return classCanHaveAbstractDeclaration(classDescriptor) || classDescriptor.isExpect();
+    }
+
+    public static boolean classCanHaveAbstractDeclaration(@NotNull ClassDescriptor classDescriptor) {
         return classDescriptor.getModality() == Modality.ABSTRACT
                || isSealedClass(classDescriptor)
                || classDescriptor.getKind() == ClassKind.ENUM_CLASS;

idea/testData/quickfix/override/dontOfferToImplementMembersForExpectedClass.kt

@@ -0,0 +1,12 @@
+// "Implement members" "false"
+// ACTION: Create test
+// ACTION: Make internal
+// ACTION: Make private
+// ACTION: Move 'A' to separate file
+
+interface I {
+    fun foo()
+}
+
+@Suppress("UNSUPPORTED_FEATURE")
+expect <caret>class A : I

idea/tests/org/jetbrains/kotlin/idea/quickfix/QuickFixTestGenerated.java

@@ -8072,6 +8072,12 @@ public class QuickFixTestGenerated extends AbstractQuickFixTest {
             doTest(fileName);
         }
 
+        @TestMetadata("dontOfferToImplementMembersForExpectedClass.kt")
+        public void testDontOfferToImplementMembersForExpectedClass() throws Exception {
+            String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/override/dontOfferToImplementMembersForExpectedClass.kt");
+            doTest(fileName);
+        }
+
         @TestMetadata("implemenAsConstructorParameter.kt")
         public void testImplemenAsConstructorParameter() throws Exception {
             String fileName = KotlinTestUtils.navigationMetadata("idea/testData/quickfix/override/implemenAsConstructorParameter.kt");