Java 8 rules for method overrides:

- report errors on implementing methods of Any in interfaces
- update testData

~~~

Java 8 override restrictions: interface can't implement a method of 'Any'
- update compiler sources

compiler/testData/codegen/box/classes/kt285.kt

@@ -1,12 +1,15 @@
 interface Trait {
     fun foo() = "O"
-    override fun toString() = "K"
+    fun bar(): String
 }
 
-class SimpleClass : Trait
+class SimpleClass : Trait {
+    override fun bar() = "K"
+}
 
+// Delegating 'toString' doesn't work, see KT-9519
 class ComplexClass : Trait by SimpleClass() {
-    override fun toString() = foo() + super.toString()
+    fun qux() = foo() + bar()
 }
 
-fun box() = ComplexClass().toString()
+fun box() = ComplexClass().qux()

compiler/testData/codegen/box/super/unqualifiedSuperWithMethodsOfAny.kt

@@ -8,10 +8,6 @@ interface IWithToString {
     override fun toString(): String
 }
 
-interface IWithDefaultToString {
-    override fun toString(): String = "I"
-}
-
 class C1 : ClassWithToString(), ISomething {
     override fun toString(): String = super.toString()
 }
@@ -20,15 +16,10 @@ class C2 : ClassWithToString(), IWithToString, ISomething  {
     override fun toString(): String = super.toString()
 }
 
-class C3 : IWithDefaultToString, ISomething  {
-    override fun toString(): String = super.toString()
-}
-
 fun box(): String {
     return when {
         C1().toString() != "C" -> "Failed #1"
         C2().toString() != "C" -> "Failed #2"
-        C3().toString() != "I" -> "Failed #3"
         else -> "OK"
     }
 }

compiler/testData/codegen/box/traits/kt5393_toString.kt

@@ -1,15 +0,0 @@
-interface A {
-    override fun toString(): String {
-        return "OK"
-    }
-}
-
-interface B : A
-
-class C : B {
-    override fun toString(): String {
-        return super.toString()
-    }
-}
-
-fun box() = "${C()}"

compiler/testData/codegen/boxInline/builders/builders.2.kt

@@ -3,8 +3,8 @@ package builders
 import java.util.ArrayList
 import java.util.HashMap
 
-interface Element {
-    fun render(builder: StringBuilder, indent: String)
+abstract class Element {
+    abstract fun render(builder: StringBuilder, indent: String)
 
     override fun toString(): String {
         val builder = StringBuilder()
@@ -13,13 +13,13 @@ interface Element {
     }
 }
 
-class TextElement(val text: String) : Element {
+class TextElement(val text: String) : Element() {
     override fun render(builder: StringBuilder, indent: String) {
         builder.append("$indent$text\n")
     }
 }
 
-abstract class Tag(val name: String) : Element {
+abstract class Tag(val name: String) : Element() {
     val children = ArrayList<Element>()
     val attributes = HashMap<String, String>()
 

compiler/testData/codegen/boxInline/builders/buildersAndLambdaCapturing.2.kt

@@ -3,8 +3,8 @@ package builders
 import java.util.ArrayList
 import java.util.HashMap
 
-interface Element {
-    fun render(builder: StringBuilder, indent: String)
+abstract class Element {
+    abstract fun render(builder: StringBuilder, indent: String)
 
     override fun toString(): String {
         val builder = StringBuilder()
@@ -13,13 +13,13 @@ interface Element {
     }
 }
 
-class TextElement(val text: String) : Element {
+class TextElement(val text: String) : Element() {
     override fun render(builder: StringBuilder, indent: String) {
         builder.append("$indent$text\n")
     }
 }
 
-abstract class Tag(val name: String) : Element {
+abstract class Tag(val name: String) : Element() {
     val children = ArrayList<Element>()
     val attributes = HashMap<String, String>()
 

compiler/testData/codegen/boxWithStdlib/dataClasses/tostring/alreadyInherited.kt

@@ -1,8 +1,8 @@
-interface SuperTrait {
+abstract class SuperTrait {
   override fun toString(): String = "!"
 }
 
-data class A(val x: Int): SuperTrait {
+data class A(val x: Int): SuperTrait() {
 }
 
 fun box(): String {

compiler/testData/diagnostics/tests/Builders.kt

@@ -49,8 +49,8 @@ fun main(args : Array<String>) {
   println(result)
 }
 
-interface Element {
-  fun render(builder : StringBuilder, indent : String)
+abstract class Element {
+  abstract fun render(builder : StringBuilder, indent : String)
 
   override fun toString() : String {
     val builder = StringBuilder()
@@ -59,13 +59,13 @@ interface Element {
   }
 }
 
-class TextElement(val text : String) : Element {
+class TextElement(val text : String) : Element() {
   override fun render(builder : StringBuilder, indent : String) {
     builder.append("$indent$text\n")
   }
 }
 
-abstract class Tag(val name : String) : Element {
+abstract class Tag(val name : String) : Element() {
   val children = ArrayList<Element>()
   val attributes = HashMap<String, String>()
 

compiler/testData/diagnostics/tests/Builders.txt

@@ -84,7 +84,8 @@ package html {
         public final override /*1*/ /*fake_override*/ fun kotlin.String.plus(): kotlin.Unit
     }
 
-    public interface Element {
+    public abstract class Element {
+        public constructor Element()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public abstract fun render(/*0*/ builder: java.lang.StringBuilder, /*1*/ indent: kotlin.String): kotlin.Unit

compiler/testData/diagnostics/tests/java8Overrides/hidingMethodOfAny.kt

@@ -0,0 +1,5 @@
+interface IA {
+    <!VIRTUAL_MEMBER_HIDDEN!>fun toString(): String<!> = "IB"
+
+    override fun equals(other: Any?): Boolean
+}

compiler/testData/diagnostics/tests/java8Overrides/hidingMethodOfAny.txt

@@ -0,0 +1,7 @@
+package
+
+public interface IA {
+    public abstract override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/java8Overrides/implementingMethodOfAny.kt

@@ -0,0 +1,9 @@
+interface IA {
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun toString(): String = "IA"<!>
+
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun equals(other: Any?): Boolean = <!SUPERCLASS_NOT_ACCESSIBLE_FROM_TRAIT!>super<!>.equals(other)<!>
+
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun hashCode(): Int {
+        return 42;
+    }<!>
+}

compiler/testData/diagnostics/tests/java8Overrides/implementingMethodOfAny.txt

@@ -0,0 +1,7 @@
+package
+
+public interface IA {
+    public open override /*1*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}

compiler/testData/diagnostics/tests/java8Overrides/notAMethodOfAny.kt

@@ -0,0 +1,3 @@
+interface IC {
+    fun toString(x: String): String = "IC$x"
+}

compiler/testData/diagnostics/tests/java8Overrides/notAMethodOfAny.txt

@@ -0,0 +1,8 @@
+package
+
+public interface IC {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+    public open fun toString(/*0*/ x: kotlin.String): kotlin.String
+}

compiler/testData/diagnostics/tests/java8Overrides/overridingMethodOfAnyChain.kt

@@ -0,0 +1,13 @@
+interface IA
+
+interface IB : IA {
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun toString(): String = "IB"<!>
+}
+
+interface IC : IB {
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun toString(): String = "IC"<!>
+}
+
+interface ID : IC {
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun toString(): String = "ID"<!>
+}

compiler/testData/diagnostics/tests/java8Overrides/overridingMethodOfAnyChain.txt

@@ -1,19 +1,24 @@
 package
 
-public interface A {
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String
-}
-
-public interface B : A {
+public interface IA {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
-public final class C : B {
-    public constructor C()
+public interface IB : IA {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}
+
+public interface IC : IB {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ fun toString(): kotlin.String
+}
+
+public interface ID : IC {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*1*/ fun toString(): kotlin.String

compiler/testData/diagnostics/tests/java8Overrides/overridingMethodOfAnyDiamond.kt

@@ -0,0 +1,11 @@
+interface ILeft {
+    override fun toString(): String
+}
+
+interface IRight {
+    override fun toString(): String
+}
+
+interface IDiamond : ILeft, IRight {
+    <!METHOD_OF_ANY_IMPLEMENTED_IN_INTERFACE!>override fun toString(): String = "IDiamond"<!>
+}

compiler/testData/diagnostics/tests/java8Overrides/overridingMethodOfAnyDiamond.txt

@@ -1,20 +1,19 @@
 package
 
-public final class C : IA, IB {
-    public constructor C()
+public interface IDiamond : ILeft, IRight {
     public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
     public open override /*2*/ fun toString(): kotlin.String
 }
 
-public interface IA {
+public interface ILeft {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String
+    public abstract override /*1*/ fun toString(): kotlin.String
 }
 
-public interface IB {
+public interface IRight {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String
+    public abstract override /*1*/ fun toString(): kotlin.String
 }

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withAmbiguousMethodOfAny.kt

@@ -1,12 +0,0 @@
-interface IA {
-    override fun toString(): String = "IA"
-}
-
-interface IB {
-    override fun toString(): String = "IB"
-}
-
-class C : IA, IB {
-    override fun toString(): String =
-            <!AMBIGUOUS_SUPER!>super<!>.<!DEBUG_INFO_ELEMENT_WITH_ERROR_TYPE!>toString<!>()
-}

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withMethodOfAnyImplementedInSuperInterface.kt

@@ -1,12 +0,0 @@
-interface A {
-    override fun toString(): String {
-        return "OK"
-    }
-}
-
-interface B : A
-
-class C : B {
-    override fun toString(): String =
-            super.toString()
-}

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withMethodOfAnyOverridenInInterface.kt

@@ -5,12 +5,4 @@ interface IWithToString {
 class A : IWithToString {
     // Should be Any#toString(), even though IWithToString defines an abstract toString.
     override fun toString(): String = super.toString()
-}
-
-interface IWithImplementedToString {
-    override fun toString(): String = "Heh"
-}
-
-class B : IWithImplementedToString {
-    override fun toString(): String = super.toString()
-}
+}

compiler/testData/diagnostics/tests/thisAndSuper/unqualifiedSuper/withMethodOfAnyOverridenInInterface.txt

@@ -7,19 +7,6 @@ public final class A : IWithToString {
     public open override /*1*/ fun toString(): kotlin.String
 }
 
-public final class B : IWithImplementedToString {
-    public constructor B()
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String
-}
-
-public interface IWithImplementedToString {
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ fun toString(): kotlin.String
-}
-
 public interface IWithToString {
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int