diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/StackValue.java b/compiler/backend/src/org/jetbrains/kotlin/codegen/StackValue.java
index 8e525da0a78..9b3c73ea6a8 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/StackValue.java
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/StackValue.java
@@ -437,10 +437,15 @@ public abstract class StackValue {
         return new CoercionValue(value, castType);
     }
 
-    public static StackValue thisOrOuter(@NotNull ExpressionCodegen codegen, @NotNull ClassDescriptor descriptor, boolean isSuper, boolean isExplicit) {
-        // Coerce this/super for traits to support traits with required classes.
+    @NotNull
+    public static StackValue thisOrOuter(
+            @NotNull ExpressionCodegen codegen,
+            @NotNull ClassDescriptor descriptor,
+            boolean isSuper,
+            boolean isExplicit
+    ) {
         // Coerce explicit 'this' for the case when it is smart cast.
-        // Do not coerce for other classes due to the 'protected' access issues (JVMS 7, 4.9.2 Structural Constraints).
+        // Do not coerce for other cases due to the 'protected' access issues (JVMS 7, 4.9.2 Structural Constraints).
         boolean coerceType = descriptor.getKind() == ClassKind.INTERFACE || (isExplicit && !isSuper);
         return new ThisOuter(codegen, descriptor, isSuper, coerceType);
     }
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/instructions/eval/operationInstructions.kt b/compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/instructions/eval/operationInstructions.kt
index 79e834e0443..672f8172017 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/instructions/eval/operationInstructions.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/cfg/pseudocode/instructions/eval/operationInstructions.kt
@@ -16,17 +16,17 @@
 
 package org.jetbrains.kotlin.cfg.pseudocode.instructions.eval
 
-import org.jetbrains.kotlin.psi.JetElement
-import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
 import org.jetbrains.kotlin.cfg.pseudocode.PseudoValue
 import org.jetbrains.kotlin.cfg.pseudocode.PseudoValueFactory
-import org.jetbrains.kotlin.cfg.pseudocode.instructions.LexicalScope
-import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionWithNext
+import org.jetbrains.kotlin.cfg.pseudocode.TypePredicate
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionVisitor
 import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionVisitorWithResult
-import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
+import org.jetbrains.kotlin.cfg.pseudocode.instructions.InstructionWithNext
+import org.jetbrains.kotlin.cfg.pseudocode.instructions.LexicalScope
 import org.jetbrains.kotlin.descriptors.ValueParameterDescriptor
-import org.jetbrains.kotlin.cfg.pseudocode.TypePredicate
+import org.jetbrains.kotlin.psi.JetElement
+import org.jetbrains.kotlin.resolve.calls.model.ResolvedCall
+import org.jetbrains.kotlin.resolve.scopes.receivers.ReceiverValue
 
 public abstract class OperationInstruction protected constructor(
         element: JetElement,
@@ -53,11 +53,6 @@ public abstract class OperationInstruction protected constructor(
     }
 }
 
-trait StrictlyValuedOperationInstruction: OperationInstruction {
-    override val outputValue: PseudoValue
-        get() = resultValue!!
-}
-
 public class CallInstruction private constructor(
         element: JetElement,
         lexicalScope: LexicalScope,
@@ -103,9 +98,12 @@ public class MagicInstruction(
         inputValues: List<PseudoValue>,
         val expectedTypes: Map<PseudoValue, TypePredicate>,
         val kind: MagicKind
-) : OperationInstruction(element, lexicalScope, inputValues), StrictlyValuedOperationInstruction {
+) : OperationInstruction(element, lexicalScope, inputValues) {
     public val synthetic: Boolean get() = outputValue.element == null
 
+    override val outputValue: PseudoValue
+        get() = resultValue!!
+
     override fun accept(visitor: InstructionVisitor) = visitor.visitMagic(this)
 
     override fun <R> accept(visitor: InstructionVisitorWithResult<R>): R = visitor.visitMagic(this)
@@ -156,7 +154,10 @@ class MergeInstruction private constructor(
         element: JetElement,
         lexicalScope: LexicalScope,
         inputValues: List<PseudoValue>
-): OperationInstruction(element, lexicalScope, inputValues), StrictlyValuedOperationInstruction {
+): OperationInstruction(element, lexicalScope, inputValues) {
+    override val outputValue: PseudoValue
+        get() = resultValue!!
+
     override fun accept(visitor: InstructionVisitor) = visitor.visitMerge(this)
 
     override fun <R> accept(visitor: InstructionVisitorWithResult<R>): R = visitor.visitMerge(this)
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
index 2b2031076d8..0cd7e590779 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/Errors.java
@@ -192,10 +192,7 @@ public interface Errors {
 
     DiagnosticFactory0<JetDelegatorByExpressionSpecifier> DELEGATION_IN_TRAIT = DiagnosticFactory0.create(ERROR);
 
-    DiagnosticFactory0<PsiElement> TRAIT_WITH_SUPERCLASS = DiagnosticFactory0.create(WARNING);
-
-    DiagnosticFactory2<JetNamedDeclaration, ClassDescriptor, ClassDescriptor> UNMET_TRAIT_REQUIREMENT =
-            DiagnosticFactory2.create(ERROR, PositioningStrategies.DECLARATION_NAME);
+    DiagnosticFactory0<PsiElement> TRAIT_WITH_SUPERCLASS = DiagnosticFactory0.create(ERROR);
 
     // Enum-specific
 
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
index f81f712aee8..060bd066846 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/diagnostics/rendering/DefaultErrorMessages.java
@@ -296,7 +296,6 @@ public class DefaultErrorMessages {
         MAP.put(DELEGATION_IN_TRAIT, "Interfaces cannot use delegation");
         MAP.put(DELEGATION_NOT_TO_TRAIT, "Only interfaces can be delegated to");
         MAP.put(DEPRECATED_TRAIT_KEYWORD, "'trait' keyword is deprecated, use 'interface' instead");
-        MAP.put(UNMET_TRAIT_REQUIREMENT, "Super interface ''{0}'' requires subclasses to extend ''{1}''", NAME, NAME);
         MAP.put(NO_CONSTRUCTOR, "This class does not have a constructor");
         MAP.put(NOT_A_CLASS, "Not a class");
         MAP.put(ILLEGAL_ESCAPE_SEQUENCE, "Illegal escape sequence");
@@ -428,7 +427,7 @@ public class DefaultErrorMessages {
         MAP.put(SUPERTYPE_INITIALIZED_IN_TRAIT, "Interfaces cannot initialize supertypes");
         MAP.put(CLASS_IN_SUPERTYPE_FOR_ENUM, "Enum class cannot inherit from classes");
         MAP.put(CONSTRUCTOR_IN_TRAIT, "An interface may not have a constructor");
-        MAP.put(TRAIT_WITH_SUPERCLASS, "Specifying a required base class for interface implementations is deprecated");
+        MAP.put(TRAIT_WITH_SUPERCLASS, "An interface cannot inherit from a class");
         MAP.put(SUPERTYPE_APPEARS_TWICE, "A supertype appears twice");
         MAP.put(FINAL_SUPERTYPE, "This type is final, so it cannot be inherited from");
         MAP.put(SINGLETON_IN_SUPERTYPE, "Cannot inherit from a singleton");
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
index 9b7736ceb38..09526f89e17 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/BodyResolver.java
@@ -426,6 +426,8 @@ public class BodyResolver {
             JetTypeReference typeReference = entry.getKey();
             JetType supertype = entry.getValue();
 
+            boolean addSupertype = true;
+
             ClassDescriptor classDescriptor = TypeUtils.getClassDescriptor(supertype);
             if (classDescriptor != null) {
                 if (ErrorUtils.isError(classDescriptor)) continue;
@@ -433,11 +435,14 @@ public class BodyResolver {
                 if (classDescriptor.getKind() != ClassKind.INTERFACE) {
                     if (supertypeOwner.getKind() == ClassKind.ENUM_CLASS) {
                         trace.report(CLASS_IN_SUPERTYPE_FOR_ENUM.on(typeReference));
+                        addSupertype = false;
                     }
                     else if (supertypeOwner.getKind() == ClassKind.INTERFACE &&
                              !classAppeared && !TypesPackage.isDynamic(supertype) /* avoid duplicate diagnostics */) {
                         trace.report(TRAIT_WITH_SUPERCLASS.on(typeReference));
+                        addSupertype = false;
                     }
+
                     if (classAppeared) {
                         trace.report(MANY_CLASSES_IN_SUPERTYPE_LIST.on(typeReference));
                     }
@@ -451,7 +456,7 @@ public class BodyResolver {
             }
 
             TypeConstructor constructor = supertype.getConstructor();
-            if (!typeConstructors.add(constructor)) {
+            if (addSupertype && !typeConstructors.add(constructor)) {
                 trace.report(SUPERTYPE_APPEARS_TWICE.on(typeReference));
             }
 
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/LazyTopDownAnalyzer.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/LazyTopDownAnalyzer.kt
index dc408c3c709..31ddc27f0a6 100644
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/LazyTopDownAnalyzer.kt
+++ b/compiler/frontend/src/org/jetbrains/kotlin/resolve/LazyTopDownAnalyzer.kt
@@ -21,16 +21,15 @@ import com.google.common.collect.Multimap
 import com.intellij.psi.PsiElement
 import com.intellij.psi.util.PsiTreeUtil
 import org.jetbrains.kotlin.descriptors.*
+import org.jetbrains.kotlin.diagnostics.Errors.CONSTRUCTOR_IN_OBJECT
 import org.jetbrains.kotlin.diagnostics.Errors.CONSTRUCTOR_IN_TRAIT
 import org.jetbrains.kotlin.diagnostics.Errors.MANY_COMPANION_OBJECTS
-import org.jetbrains.kotlin.diagnostics.Errors.CONSTRUCTOR_IN_OBJECT
 import org.jetbrains.kotlin.diagnostics.Errors.UNSUPPORTED
 import org.jetbrains.kotlin.name.FqName
 import org.jetbrains.kotlin.psi.*
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowInfo
 import org.jetbrains.kotlin.resolve.lazy.*
 import org.jetbrains.kotlin.resolve.lazy.descriptors.LazyClassDescriptor
-import org.jetbrains.kotlin.resolve.resolveUtil.checkTraitRequirements
 import org.jetbrains.kotlin.resolve.varianceChecker.VarianceChecker
 import java.util.ArrayList
 import javax.inject.Inject
@@ -244,8 +243,6 @@ public class LazyTopDownAnalyzer {
         declarationResolver!!.checkRedeclarationsInPackages(topLevelDescriptorProvider!!, topLevelFqNames)
         declarationResolver!!.checkRedeclarations(c)
 
-        checkTraitRequirements(c.getDeclaredClasses(), trace!!)
-
         overrideResolver!!.check(c)
 
         varianceChecker!!.check(c)
diff --git a/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkTraitRequirements.kt b/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkTraitRequirements.kt
deleted file mode 100644
index ac6851e1a54..00000000000
--- a/compiler/frontend/src/org/jetbrains/kotlin/resolve/checkTraitRequirements.kt
+++ /dev/null
@@ -1,62 +0,0 @@
-/*
- * Copyright 2010-2015 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.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.jetbrains.kotlin.resolve.resolveUtil
-
-import org.jetbrains.kotlin.descriptors.ClassDescriptor
-import org.jetbrains.kotlin.resolve.DescriptorUtils
-import org.jetbrains.kotlin.types.TypeUtils
-import org.jetbrains.kotlin.builtins.KotlinBuiltIns
-import org.jetbrains.kotlin.diagnostics.Errors
-import org.jetbrains.kotlin.psi.JetClassOrObject
-import org.jetbrains.kotlin.descriptors.ClassDescriptorWithResolutionScopes
-import org.jetbrains.kotlin.resolve.BindingTrace
-import org.jetbrains.kotlin.resolve.descriptorUtil.getSuperClassOrAny
-
-fun checkTraitRequirements(c: Map<JetClassOrObject, ClassDescriptorWithResolutionScopes>, trace: BindingTrace) {
-    for ((classOrObject, descriptor) in c.entrySet()) {
-        if (DescriptorUtils.isTrait(descriptor)) continue
-
-        val satisfiedRequirements = getSuperClassesReachableByClassInheritance(descriptor)
-        for (superTrait in getAllSuperTraits(descriptor)) {
-            for (traitSupertype in superTrait.getDefaultType().getConstructor().getSupertypes()) {
-                val traitSuperClass = traitSupertype.getConstructor().getDeclarationDescriptor()
-                if (DescriptorUtils.isClass(traitSuperClass) && traitSuperClass !in satisfiedRequirements) {
-                    trace.report(Errors.UNMET_TRAIT_REQUIREMENT.on(classOrObject, superTrait, traitSuperClass as ClassDescriptor))
-                }
-            }
-        }
-    }
-}
-
-private fun getAllSuperTraits(descriptor: ClassDescriptor): List<ClassDescriptor> {
-    @suppress("UNCHECKED_CAST")
-    return TypeUtils.getAllSupertypes(descriptor.getDefaultType())
-            .map { supertype -> supertype.getConstructor().getDeclarationDescriptor() }
-            .filter { superClass -> DescriptorUtils.isTrait(superClass) } as List<ClassDescriptor>
-}
-
-private fun getSuperClassesReachableByClassInheritance(
-        descriptor: ClassDescriptor,
-        result: MutableSet<ClassDescriptor> = hashSetOf()
-): Set<ClassDescriptor> {
-    val superClass = descriptor.getSuperClassOrAny()
-    result.add(superClass)
-    if (!KotlinBuiltIns.isAny(superClass)) {
-        getSuperClassesReachableByClassInheritance(superClass, result)
-    }
-    return result
-}
diff --git a/compiler/testData/codegen/box/bridges/complexMultiInheritance.kt b/compiler/testData/codegen/box/bridges/complexMultiInheritance.kt
index 2128aa8fab4..6d03b1f1f6e 100644
--- a/compiler/testData/codegen/box/bridges/complexMultiInheritance.kt
+++ b/compiler/testData/codegen/box/bridges/complexMultiInheritance.kt
@@ -2,8 +2,6 @@ open class A {
     open fun foo(): Any = "A"
 }
 
-interface B : A
-
 open class C : A() {
     override fun foo(): Int = 222
 }
@@ -12,14 +10,13 @@ interface D {
     fun foo(): Number
 }
 
-class E : B, C(), D
+class E : C(), D
 
 fun box(): String {
     val e = E()
     if (e.foo() != 222) return "Fail 1"
     if ((e : D).foo() != 222) return "Fail 2"
     if ((e : C).foo() != 222) return "Fail 3"
-    if ((e : B).foo() != 222) return "Fail 4"
-    if ((e : A).foo() != 222) return "Fail 5"
+    if ((e : A).foo() != 222) return "Fail 4"
     return "OK"
 }
diff --git a/compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt b/compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt
deleted file mode 100644
index fee76a53e9c..00000000000
--- a/compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-abstract class A {
-    abstract fun foo(): Any
-}
-
-interface B {
-    fun foo(): String = "B"
-}
-
-interface C : A, B
-
-class D : A(), C
-
-fun box(): String {
-    val d = D()
-    val r = d.foo() + (d : C).foo() + (d : B).foo() + (d : A).foo()
-    return if (r == "BBBB") "OK" else "Fail: $r"
-}
diff --git a/compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt b/compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt
deleted file mode 100644
index 997a5c33760..00000000000
--- a/compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt
+++ /dev/null
@@ -1,15 +0,0 @@
-open class A {
-    open fun foo(): Any = "A"
-}
-
-interface B : A {
-    override fun foo(): String = "B"
-}
-
-class C : A(), B
-
-fun box(): String {
-    val c = C()
-    val r = c.foo() + (c : B).foo() + (c : A).foo()
-    return if (r == "BBB") "OK" else "Fail: $r"
-}
diff --git a/compiler/testData/codegen/box/classes/kt3862.kt b/compiler/testData/codegen/box/classes/kt3862.kt
deleted file mode 100644
index 6f020ac8ab0..00000000000
--- a/compiler/testData/codegen/box/classes/kt3862.kt
+++ /dev/null
@@ -1,18 +0,0 @@
-open class A<T> {
-    open fun foo(a: T): Int = 2
-}
-
-interface B<T> : A<T> {
-    override fun foo(a: T): Int = 1
-}
-
-class D : B<Int>, A<Int>() {
-    fun boo(): Int {
-        return super<B>.foo(1)
-    }
-}
-
-fun box(): String {
-    if (D().boo() != 1) return "Fail"
-    return "OK"
-}
diff --git a/compiler/testData/codegen/box/closures/closureInsideClosure/propertyAndFunctionNameClash.kt b/compiler/testData/codegen/box/closures/closureInsideClosure/propertyAndFunctionNameClash.kt
index b19e4b61b0d..ce7572bcabb 100644
--- a/compiler/testData/codegen/box/closures/closureInsideClosure/propertyAndFunctionNameClash.kt
+++ b/compiler/testData/codegen/box/closures/closureInsideClosure/propertyAndFunctionNameClash.kt
@@ -24,8 +24,8 @@ class LI : ListTag() {}
 public fun ListTag.item(body: LI.() -> Unit): Unit {}
 fun HtmlTag.a(contents: A.() -> Unit) {}
 
-interface A : HtmlTag {
-    public var text: String
+abstract class A : HtmlTag() {
+    public abstract var text: String
 }
 
 fun listOf(vararg strings: String): List<String> {
@@ -34,4 +34,4 @@ fun listOf(vararg strings: String): List<String> {
         list.add(s)
     }
     return list
-}
\ No newline at end of file
+}
diff --git a/compiler/testData/codegen/box/properties/traitExtendsClass.kt b/compiler/testData/codegen/box/properties/traitExtendsClass.kt
deleted file mode 100644
index d1aa10bec1a..00000000000
--- a/compiler/testData/codegen/box/properties/traitExtendsClass.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-open class Base {
-    val pr : String = "OK"
-}
-
-interface Trait : Base {
-    fun f() : String {
-        return this.pr
-    }
-}
-
-class A : Trait, Base() {
-
-}
-
-fun box() : String {
-    return if (A().f() == A().pr)  "OK" else "fail"
-}
\ No newline at end of file
diff --git a/compiler/testData/codegen/box/super/kt3538.kt b/compiler/testData/codegen/box/super/kt3538.kt
deleted file mode 100644
index 7186da045ec..00000000000
--- a/compiler/testData/codegen/box/super/kt3538.kt
+++ /dev/null
@@ -1,21 +0,0 @@
-open class Base {
-    open fun sayHello(): String {
-        return "O"
-    }
-}
-
-interface Trait: Base {
-    override fun sayHello(): String {
-        return "K"
-    }
-}
-
-class Derived(): Base(), Trait {
-    override fun sayHello(): String {
-        return super<Base>.sayHello() + super<Trait>.sayHello()
-    }
-}
-
-fun box(): String {
-    return Derived().sayHello()
-}
\ No newline at end of file
diff --git a/compiler/testData/codegen/box/traits/withRequired/generic.kt b/compiler/testData/codegen/box/traits/withRequired/generic.kt
deleted file mode 100644
index 75d26e62299..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/generic.kt
+++ /dev/null
@@ -1,15 +0,0 @@
-open class AL<T> {
-    fun get(index: Int) : T? = null
-}
-
-interface ALE<T> : AL<T> {
-    fun getOrValue(index: Int, value : T) : T = get(index) ?: value
-}
-
-class SmartArrayList() : ALE<String>, AL<String>() {
-}
-
-fun box() : String {
-  val c = SmartArrayList()
-  return if("239" == c.getOrValue(0, "239")) "OK" else "fail"
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/genericProperty.kt b/compiler/testData/codegen/box/traits/withRequired/genericProperty.kt
deleted file mode 100644
index 2579ef900b5..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/genericProperty.kt
+++ /dev/null
@@ -1,19 +0,0 @@
-abstract class Base<T> {
-    abstract var s: T
-}
-
-interface Trait<T> : Base<T> {
-    var value : T
-        get() = s
-        set(value) { s = value }
-}
-
-class Derived : Trait<String>, Base<String>() {
-    override var s = "Fail"
-}
-
-fun box(): String {
-    val d = Derived()
-    d.value = "OK"
-    return d.value
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/kt1936_2.kt b/compiler/testData/codegen/box/traits/withRequired/kt1936_2.kt
deleted file mode 100644
index 8c17c464421..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/kt1936_2.kt
+++ /dev/null
@@ -1,15 +0,0 @@
-open class MyClass(param : String) {
-    var propterty = param
-}
-
-interface MyTrait : MyClass
-{
-    fun foo()  = propterty
-}
-
-open class B(param : String) : MyTrait, MyClass(param)
-{
-    override fun foo() = super<MyTrait>.foo()
-}
-
-fun box()= B("OK").foo()
diff --git a/compiler/testData/codegen/box/traits/withRequired/kt2963.kt b/compiler/testData/codegen/box/traits/withRequired/kt2963.kt
deleted file mode 100644
index 2d463906975..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/kt2963.kt
+++ /dev/null
@@ -1,15 +0,0 @@
-open class Base
-
-interface Derived : Base {
-    fun foo(): String {
-        return object {
-            fun bar() = baz(this@Derived)
-        }.bar()
-    }
-}
-
-class DerivedImpl : Derived, Base()
-
-fun baz(b: Base) = "OK"
-
-fun box() = DerivedImpl().foo()
diff --git a/compiler/testData/codegen/box/traits/withRequired/kt3413.kt b/compiler/testData/codegen/box/traits/withRequired/kt3413.kt
deleted file mode 100644
index a27f370230f..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/kt3413.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-interface Trait<T : Enum<T>> : Enum<T> {
-    val value : String get() = name()
-}
-
-enum class E : Trait<E> {
-    OK
-}
-
-fun box() = E.OK.value
diff --git a/compiler/testData/codegen/box/traits/withRequired/kt3429.kt b/compiler/testData/codegen/box/traits/withRequired/kt3429.kt
deleted file mode 100644
index 18a55c90083..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/kt3429.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-open class Base {
-    open fun sayHello(): String{
-        return "fail"
-    }
-}
-
-interface Trait: Base {
-    override fun sayHello(): String {
-        return "OK"
-    }
-}
-
-class Derived(): Base(), Trait
-
-fun box() : String {
-    return Derived().sayHello()
-}
\ No newline at end of file
diff --git a/compiler/testData/codegen/box/traits/withRequired/property.kt b/compiler/testData/codegen/box/traits/withRequired/property.kt
deleted file mode 100644
index f6945f36518..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/property.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-open class Base {
-    var s = "Fail"
-}
-
-interface Trait : Base {
-    var value : String
-        get() = s
-        set(value) { s = value }
-}
-
-class Derived : Trait, Base()
-
-fun box(): String {
-    val d = Derived()
-    d.value = "OK"
-    return d.value
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/propertyViaBridge.kt b/compiler/testData/codegen/box/traits/withRequired/propertyViaBridge.kt
deleted file mode 100644
index 96ed04b4aa6..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/propertyViaBridge.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-open class Base
-
-interface Trait : Base {
-    private val value : String
-        get() = "OK"
-        
-    override fun toString() = object {
-        fun foo() = value
-    }.foo()
-}
-
-class Derived : Trait, Base()
-
-fun box() = "${Derived()}"
diff --git a/compiler/testData/codegen/box/traits/withRequired/simple.kt b/compiler/testData/codegen/box/traits/withRequired/simple.kt
deleted file mode 100644
index 2a4b89e189d..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/simple.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-interface Trait : java.lang.Object {
-    fun foo(): String = "239 " + toString()
-}
-
-class Impl : Trait, java.lang.Object() {
-    override fun toString() = "Impl"
-}
-
-fun box(): String {
-    return if ("239 Impl" == Impl().foo()) "OK" else "Fail"
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/super.kt b/compiler/testData/codegen/box/traits/withRequired/super.kt
deleted file mode 100644
index 064084c26ba..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/super.kt
+++ /dev/null
@@ -1,18 +0,0 @@
-open class Base {
-    open fun foo() : String {
-      return "fail"
-    }
-}
-
-interface Derived : Base {
-    override fun foo() : String {
-        //super.foo()
-        return "OK"
-    }
-}
-
-class DerivedImpl : Derived, Base()
-
-fun box(): String {
-    return DerivedImpl().foo()
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/superViaBridge.kt b/compiler/testData/codegen/box/traits/withRequired/superViaBridge.kt
deleted file mode 100644
index 7bd8a552608..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/superViaBridge.kt
+++ /dev/null
@@ -1,22 +0,0 @@
-open class Base {
-    open fun foo() { }
-    open fun foo2() { }
-}
-
-interface Derived : Base {
-    override fun foo() {
-        object {
-            fun bar() {
-                //super<Base>@Derived.foo2()
-                this@Derived.foo2()
-            }
-        }.bar()
-    }
-}
-
-class DerivedImpl : Derived, Base()
-
-fun box(): String {
-    DerivedImpl().foo()
-    return "OK"
-}
diff --git a/compiler/testData/codegen/box/traits/withRequired/traitFuncCall.kt b/compiler/testData/codegen/box/traits/withRequired/traitFuncCall.kt
deleted file mode 100644
index b704ceb9e2d..00000000000
--- a/compiler/testData/codegen/box/traits/withRequired/traitFuncCall.kt
+++ /dev/null
@@ -1,17 +0,0 @@
-open class Foo() {
-    public fun k(): String = "K"
-}
-
-
-interface T: Foo {
-    public fun xyzzy(): String = o() + k()
-    public fun o(): String
-}
-
-class TImpl(): Foo(), T {
-    public override fun o(): String = "O"
-}
-
-fun box(): String {
-    return TImpl().xyzzy()
-}
diff --git a/compiler/testData/diagnostics/tests/cast/neverSucceeds/NoGenericsRelated.kt b/compiler/testData/diagnostics/tests/cast/neverSucceeds/NoGenericsRelated.kt
index 83a09248321..da97c3cee27 100644
--- a/compiler/testData/diagnostics/tests/cast/neverSucceeds/NoGenericsRelated.kt
+++ b/compiler/testData/diagnostics/tests/cast/neverSucceeds/NoGenericsRelated.kt
@@ -5,7 +5,7 @@ interface T3
 open class OC1: T1
 open class OC2: OC1(), T2
 class FC1: OC2(), T3
-interface T4: OC1
+interface T4: <!TRAIT_WITH_SUPERCLASS!>OC1<!>
 interface T5: T2
 
 fun test<TP1: OC1, TP2: T2, TP3: OC2>(
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.kt b/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.kt
deleted file mode 100644
index 1b1c68bf368..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-open class Required
-
-interface Trait : <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-abstract <!UNMET_TRAIT_REQUIREMENT!>class Abstract<!> : Trait
-
-abstract <!UNMET_TRAIT_REQUIREMENT!>class AbstractDerived<!> : Abstract()
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.txt b/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.txt
deleted file mode 100644
index 95d5f579e9c..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.txt
+++ /dev/null
@@ -1,28 +0,0 @@
-package
-
-internal abstract class Abstract : Trait {
-    public constructor Abstract()
-    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
-}
-
-internal abstract class AbstractDerived : Abstract {
-    public constructor AbstractDerived()
-    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
-}
-
-internal open class Required {
-    public constructor Required()
-    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
-}
-
-internal interface Trait : Required {
-    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
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.kt b/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.kt
deleted file mode 100644
index 2be1de89415..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-open class Required
-
-interface A : <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-val a = <!UNMET_TRAIT_REQUIREMENT!>object<!> : A {}
-val b: A = object : A, Required() {}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.txt b/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.txt
deleted file mode 100644
index be0e2485e80..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.txt
+++ /dev/null
@@ -1,17 +0,0 @@
-package
-
-internal val a: A
-internal val b: A
-
-internal interface A : Required {
-    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
-}
-
-internal open class Required {
-    public constructor Required()
-    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
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.kt b/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.kt
deleted file mode 100644
index ab90db2cd01..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-open class Generic<T>
-
-interface A : <!TRAIT_WITH_SUPERCLASS!>Generic<Int><!>
-
-interface B : <!TRAIT_WITH_SUPERCLASS!>Generic<String><!>
-
-<!UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT!>class Y<!> : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>A, B<!>
-class Z : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>A, B, Generic<Int>()<!>
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.txt b/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.txt
deleted file mode 100644
index 02273eb1cff..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.txt
+++ /dev/null
@@ -1,34 +0,0 @@
-package
-
-internal interface A : Generic<kotlin.Int> {
-    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
-}
-
-internal interface B : Generic<kotlin.String> {
-    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
-}
-
-internal open class Generic</*0*/ T> {
-    public constructor Generic</*0*/ T>()
-    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
-}
-
-internal final class Y : A, B {
-    public constructor Y()
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal final class Z : A, B, Generic<kotlin.Int> {
-    public constructor Z()
-    public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*3*/ /*fake_override*/ fun toString(): kotlin.String
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.kt b/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.kt
deleted file mode 100644
index 426c86fda20..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.kt
+++ /dev/null
@@ -1,13 +0,0 @@
-open class Base {
-}
-
-interface Derived: <!TRAIT_WITH_SUPERCLASS!>Base<!> {
-    fun foo() {
-        f1(this@Derived)
-    }
-}
-
-<!UNMET_TRAIT_REQUIREMENT!>class DerivedImpl<!>(): Derived {}
-<!UNMET_TRAIT_REQUIREMENT!>object ObjectImpl<!>: Derived {}
-
-fun f1(b: Base) = b
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.txt b/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.txt
deleted file mode 100644
index c1b7ea9b199..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/kt3006.txt
+++ /dev/null
@@ -1,33 +0,0 @@
-package
-
-internal fun f1(/*0*/ b: Base): Base
-
-internal open class Base {
-    public constructor Base()
-    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
-}
-
-internal interface Derived : Base {
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    internal open fun foo(): kotlin.Unit
-    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal final class DerivedImpl : Derived {
-    public constructor DerivedImpl()
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    internal open 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
-}
-
-internal object ObjectImpl : Derived {
-    private constructor ObjectImpl()
-    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    internal open 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
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.kt b/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.kt
deleted file mode 100644
index 7c8060832e7..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.kt
+++ /dev/null
@@ -1,4 +0,0 @@
-open class A
-open class B
-
-interface C : <!TRAIT_WITH_SUPERCLASS!>A<!>, <!MANY_CLASSES_IN_SUPERTYPE_LIST!>B<!>
\ No newline at end of file
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.txt b/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.txt
deleted file mode 100644
index 7f2d5e3eedd..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.txt
+++ /dev/null
@@ -1,21 +0,0 @@
-package
-
-internal open class A {
-    public constructor 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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal open class B {
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal interface C : A, B {
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.kt b/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.kt
deleted file mode 100644
index 693178cab97..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-open class Required
-
-interface A : <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-interface B : A, <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-interface C : <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-interface D : B, <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-<!UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT!>class W<!> : D
-class X : D, Required()
-<!UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT, UNMET_TRAIT_REQUIREMENT!>class Y<!> : C, D
-class Z : D, C, Required()
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.txt b/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.txt
deleted file mode 100644
index 350b5b50b2f..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.txt
+++ /dev/null
@@ -1,60 +0,0 @@
-package
-
-internal interface A : Required {
-    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
-}
-
-internal interface B : A, Required {
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal interface C : Required {
-    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
-}
-
-internal interface D : B, Required {
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal open class Required {
-    public constructor Required()
-    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
-}
-
-internal final class W : D {
-    public constructor W()
-    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
-}
-
-internal final class X : D, Required {
-    public constructor X()
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal final class Y : C, D {
-    public constructor Y()
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal final class Z : D, C, Required {
-    public constructor Z()
-    public open override /*3*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
-    public open override /*3*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public open override /*3*/ /*fake_override*/ fun toString(): kotlin.String
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.kt b/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.kt
deleted file mode 100644
index 99cea06bcfc..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-open class RequiredBase
-
-interface Trait : <!TRAIT_WITH_SUPERCLASS!>RequiredBase<!>
-
-open class RequiredDerived : RequiredBase()
-
-<!UNMET_TRAIT_REQUIREMENT!>class A<!> : Trait
-class B : Trait, RequiredDerived()
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.txt b/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.txt
deleted file mode 100644
index 384a8cdec9f..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.txt
+++ /dev/null
@@ -1,35 +0,0 @@
-package
-
-internal final class A : Trait {
-    public constructor 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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal final class B : Trait, RequiredDerived {
-    public constructor B()
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal open class RequiredBase {
-    public constructor RequiredBase()
-    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
-}
-
-internal open class RequiredDerived : RequiredBase {
-    public constructor RequiredDerived()
-    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
-}
-
-internal interface Trait : RequiredBase {
-    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
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.kt b/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.kt
deleted file mode 100644
index b771f2d842b..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-open class Required(val value: String)
-
-interface First : <!TRAIT_WITH_SUPERCLASS!>Required<!>
-
-interface Second : First
-
-<!UNMET_TRAIT_REQUIREMENT!>class Y<!> : Second
-class Z : Second, Required(":o)")
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.txt b/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.txt
deleted file mode 100644
index 9be8c52256c..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.txt
+++ /dev/null
@@ -1,39 +0,0 @@
-package
-
-internal interface First : Required {
-    internal final override /*1*/ /*fake_override*/ val value: kotlin.String
-    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
-}
-
-internal open class Required {
-    public constructor Required(/*0*/ value: kotlin.String)
-    internal final val value: kotlin.String
-    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
-}
-
-internal interface Second : First {
-    internal final override /*1*/ /*fake_override*/ val value: kotlin.String
-    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
-}
-
-internal final class Y : Second {
-    public constructor Y()
-    internal final override /*1*/ /*fake_override*/ val value: kotlin.String
-    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
-}
-
-internal final class Z : Second, Required {
-    public constructor Z()
-    internal final override /*2*/ /*fake_override*/ val value: kotlin.String
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/traitSupertypeList.kt b/compiler/testData/diagnostics/tests/traitWithRequired/traitSupertypeList.kt
index af9ead46dec..71873609eb9 100644
--- a/compiler/testData/diagnostics/tests/traitWithRequired/traitSupertypeList.kt
+++ b/compiler/testData/diagnostics/tests/traitWithRequired/traitSupertypeList.kt
@@ -1,6 +1,6 @@
 open class bar()
 
-interface Foo<!CONSTRUCTOR_IN_TRAIT!>()<!> : <!TRAIT_WITH_SUPERCLASS!>bar<!><!SUPERTYPE_INITIALIZED_IN_TRAIT!>()<!>, <!MANY_CLASSES_IN_SUPERTYPE_LIST, SUPERTYPE_APPEARS_TWICE!>bar<!>, <!MANY_CLASSES_IN_SUPERTYPE_LIST, SUPERTYPE_APPEARS_TWICE!>bar<!> {
+interface Foo<!CONSTRUCTOR_IN_TRAIT!>()<!> : <!TRAIT_WITH_SUPERCLASS!>bar<!><!SUPERTYPE_INITIALIZED_IN_TRAIT!>()<!>, <!MANY_CLASSES_IN_SUPERTYPE_LIST!>bar<!>, <!MANY_CLASSES_IN_SUPERTYPE_LIST, SUPERTYPE_APPEARS_TWICE!>bar<!> {
 }
 
 interface Foo2 : <!TRAIT_WITH_SUPERCLASS!>bar<!>, Foo {
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.kt b/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.kt
deleted file mode 100644
index d9788d49103..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-open class Generic<T>
-
-interface A : <!TRAIT_WITH_SUPERCLASS!>Generic<String><!>
-
-interface B : <!TRAIT_WITH_SUPERCLASS!>Generic<Int><!>
-
-interface C : <!INCONSISTENT_TYPE_PARAMETER_VALUES!>A, B<!>
diff --git a/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.txt b/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.txt
deleted file mode 100644
index 0ecd458ba78..00000000000
--- a/compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.txt
+++ /dev/null
@@ -1,26 +0,0 @@
-package
-
-internal interface A : Generic<kotlin.String> {
-    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
-}
-
-internal interface B : Generic<kotlin.Int> {
-    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
-}
-
-internal interface C : A, B {
-    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*/ /*fake_override*/ fun toString(): kotlin.String
-}
-
-internal open class Generic</*0*/ T> {
-    public constructor Generic</*0*/ T>()
-    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
-}
diff --git a/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt b/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt
deleted file mode 100644
index 0814ecc70ac..00000000000
--- a/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt
+++ /dev/null
@@ -1,23 +0,0 @@
-package test
-
-abstract class A {
-    abstract fun foo()
-}
-
-interface X : A {
-    fun bar() {
-    }
-}
-
-open class B() : A() {
-    override fun foo() {
-    }
-}
-
-class C() : A(), X {
-    override fun foo() {
-    }
-}
-
-class D(val c: C) : B(), X by c {
-}
\ No newline at end of file
diff --git a/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.txt b/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.txt
deleted file mode 100644
index 22c894c0e85..00000000000
--- a/compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.txt
+++ /dev/null
@@ -1,30 +0,0 @@
-package test
-
-internal abstract class A {
-    /*primary*/ public constructor A()
-    internal abstract fun foo(): kotlin.Unit
-}
-
-internal open class B : test.A {
-    /*primary*/ public constructor B()
-    internal open override /*1*/ fun foo(): kotlin.Unit
-}
-
-internal final class C : test.A, test.X {
-    /*primary*/ public constructor C()
-    internal open override /*1*/ /*fake_override*/ fun bar(): kotlin.Unit
-    internal open override /*2*/ fun foo(): kotlin.Unit
-}
-
-internal final class D : test.B, test.X {
-    /*primary*/ public constructor D(/*0*/ c: test.C)
-    internal final val c: test.C
-        internal final fun <get-c>(): test.C
-    internal open override /*1*/ /*delegation*/ fun bar(): kotlin.Unit
-    internal open override /*2*/ /*fake_override*/ fun foo(): kotlin.Unit
-}
-
-internal interface X : test.A {
-    internal open fun bar(): kotlin.Unit
-    internal abstract override /*1*/ /*fake_override*/ fun foo(): kotlin.Unit
-}
diff --git a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
index 84293d09ec6..f88255e2293 100644
--- a/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/checkers/JetDiagnosticsTestGenerated.java
@@ -13412,58 +13412,10 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
         @TestDataPath("$PROJECT_ROOT")
         @RunWith(JUnit3RunnerWithInners.class)
         public static class TraitWithRequired extends AbstractJetDiagnosticsTest {
-            @TestMetadata("abstractClass.kt")
-            public void testAbstractClass() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/abstractClass.kt");
-                doTest(fileName);
-            }
-
             public void testAllFilesPresentInTraitWithRequired() throws Exception {
                 JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/diagnostics/tests/traitWithRequired"), Pattern.compile("^(.+)\\.kt$"), true);
             }
 
-            @TestMetadata("anonymousObjectExtendsTraitWithRequired.kt")
-            public void testAnonymousObjectExtendsTraitWithRequired() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/anonymousObjectExtendsTraitWithRequired.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("differentGenericArguments.kt")
-            public void testDifferentGenericArguments() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/differentGenericArguments.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("kt3006.kt")
-            public void testKt3006() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/kt3006.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("manyRequirementsDisallowed.kt")
-            public void testManyRequirementsDisallowed() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/manyRequirementsDisallowed.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("manyTraitsRequireSameClass.kt")
-            public void testManyTraitsRequireSameClass() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/manyTraitsRequireSameClass.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("requirementFulfilledBySubclass.kt")
-            public void testRequirementFulfilledBySubclass() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/requirementFulfilledBySubclass.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("traitExtendsTraitWithRequired.kt")
-            public void testTraitExtendsTraitWithRequired() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/traitExtendsTraitWithRequired.kt");
-                doTest(fileName);
-            }
-
             @TestMetadata("traitRequiresAny.kt")
             public void testTraitRequiresAny() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/traitRequiresAny.kt");
@@ -13475,12 +13427,6 @@ public class JetDiagnosticsTestGenerated extends AbstractJetDiagnosticsTest {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/traitSupertypeList.kt");
                 doTest(fileName);
             }
-
-            @TestMetadata("uninheritableTraitDifferentGenericArguments.kt")
-            public void testUninheritableTraitDifferentGenericArguments() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/diagnostics/tests/traitWithRequired/uninheritableTraitDifferentGenericArguments.kt");
-                doTest(fileName);
-            }
         }
 
         @TestMetadata("compiler/testData/diagnostics/tests/typedefs")
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BridgeTest.kt b/compiler/tests/org/jetbrains/kotlin/codegen/BridgeTest.kt
index 3f77925905a..59b2f870b99 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BridgeTest.kt
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BridgeTest.kt
@@ -66,10 +66,11 @@ class BridgeTest : TestCase() {
      *    is either reachable from D or is reachable from any abstract super-declaration of F (or both). This condition is effectively
      *    equivalent to the compiler guarantee that each class inherits not more than one implementation of each function.
      *
-     * NOTE: abstract fake overrides CAN have concrete super-declarations! (traits with required classes)
-     *
-     * NOTE 2: the graph validation procedure probably doesn't cover all the possible cases compared to the analogous code in the compiler.
+     * NOTE: the graph validation procedure probably doesn't cover all the possible cases compared to the analogous code in the compiler.
      *         There may be bugs here and they should be fixed accordingly.
+     *
+     * TODO: also verify that no abstract fake override has a concrete super-declaration.
+     *       This was previously possible via traits with required classes.
      */
     private fun graph(vararg edges: Pair<Fun, Fun>) {
         for ((from, to) in edges) {
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java
index 9e20827179e..2563cbf4ed9 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/generated/BlackBoxCodegenTestGenerated.java
@@ -379,12 +379,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
-        @TestMetadata("fakeOverrideInTraitWithRequiredFromTraitImpl.kt")
-        public void testFakeOverrideInTraitWithRequiredFromTraitImpl() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("fakeOverrideOfPropertySetterInTraitImpl.kt")
         public void testFakeOverrideOfPropertySetterInTraitImpl() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/fakeOverrideOfPropertySetterInTraitImpl.kt");
@@ -571,12 +565,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
-        @TestMetadata("traitWithRequiredCovariantOverride.kt")
-        public void testTraitWithRequiredCovariantOverride() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("twoParentsWithDifferentMethodsTwoBridges.kt")
         public void testTwoParentsWithDifferentMethodsTwoBridges() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/twoParentsWithDifferentMethodsTwoBridges.kt");
@@ -1348,12 +1336,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
-        @TestMetadata("kt3862.kt")
-        public void testKt3862() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/kt3862.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("kt454.kt")
         public void testKt454() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/classes/kt454.kt");
@@ -6196,12 +6178,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
-        @TestMetadata("traitExtendsClass.kt")
-        public void testTraitExtendsClass() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/traitExtendsClass.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("twoAnnotatedExtensionPropertiesWithoutBackingFields.kt")
         public void testTwoAnnotatedExtensionPropertiesWithoutBackingFields() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/properties/twoAnnotatedExtensionPropertiesWithoutBackingFields.kt");
@@ -6796,12 +6772,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             doTest(fileName);
         }
 
-        @TestMetadata("kt3538.kt")
-        public void testKt3538() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/super/kt3538.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("kt4173.kt")
         public void testKt4173() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/super/kt4173.kt");
@@ -7110,87 +7080,6 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/traitWithPrivateExtension.kt");
             doTest(fileName);
         }
-
-        @TestMetadata("compiler/testData/codegen/box/traits/withRequired")
-        @TestDataPath("$PROJECT_ROOT")
-        @RunWith(JUnit3RunnerWithInners.class)
-        public static class WithRequired extends AbstractBlackBoxCodegenTest {
-            public void testAllFilesPresentInWithRequired() throws Exception {
-                JetTestUtils.assertAllTestsPresentByMetadata(this.getClass(), new File("compiler/testData/codegen/box/traits/withRequired"), Pattern.compile("^(.+)\\.kt$"), true);
-            }
-
-            @TestMetadata("generic.kt")
-            public void testGeneric() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/generic.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("genericProperty.kt")
-            public void testGenericProperty() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/genericProperty.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("kt1936_2.kt")
-            public void testKt1936_2() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/kt1936_2.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("kt2963.kt")
-            public void testKt2963() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/kt2963.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("kt3413.kt")
-            public void testKt3413() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/kt3413.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("kt3429.kt")
-            public void testKt3429() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/kt3429.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("property.kt")
-            public void testProperty() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/property.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("propertyViaBridge.kt")
-            public void testPropertyViaBridge() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/propertyViaBridge.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("simple.kt")
-            public void testSimple() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/simple.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("super.kt")
-            public void testSuper() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/super.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("superViaBridge.kt")
-            public void testSuperViaBridge() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/superViaBridge.kt");
-                doTest(fileName);
-            }
-
-            @TestMetadata("traitFuncCall.kt")
-            public void testTraitFuncCall() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/traits/withRequired/traitFuncCall.kt");
-                doTest(fileName);
-            }
-        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/typeInfo")
diff --git a/compiler/tests/org/jetbrains/kotlin/jvm/compiler/LoadJavaTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/jvm/compiler/LoadJavaTestGenerated.java
index 33bfdde1adb..89d0b94765f 100644
--- a/compiler/tests/org/jetbrains/kotlin/jvm/compiler/LoadJavaTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/jvm/compiler/LoadJavaTestGenerated.java
@@ -3985,12 +3985,6 @@ public class LoadJavaTestGenerated extends AbstractLoadJavaTest {
                 doTestCompiledKotlin(fileName);
             }
 
-            @TestMetadata("NoDelegationForFunctionInheritedFromTraitSuperClass.kt")
-            public void testNoDelegationForFunctionInheritedFromTraitSuperClass() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt");
-                doTestCompiledKotlin(fileName);
-            }
-
             @TestMetadata("NoSamAdapter.kt")
             public void testNoSamAdapter() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoSamAdapter.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/jvm/runtime/JvmRuntimeDescriptorLoaderTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/jvm/runtime/JvmRuntimeDescriptorLoaderTestGenerated.java
index 14267cfa3c1..9e1c62d4995 100644
--- a/compiler/tests/org/jetbrains/kotlin/jvm/runtime/JvmRuntimeDescriptorLoaderTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/jvm/runtime/JvmRuntimeDescriptorLoaderTestGenerated.java
@@ -2142,12 +2142,6 @@ public class JvmRuntimeDescriptorLoaderTestGenerated extends AbstractJvmRuntimeD
                 doTest(fileName);
             }
 
-            @TestMetadata("NoDelegationForFunctionInheritedFromTraitSuperClass.kt")
-            public void testNoDelegationForFunctionInheritedFromTraitSuperClass() throws Exception {
-                String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt");
-                doTest(fileName);
-            }
-
             @TestMetadata("NoSamAdapter.kt")
             public void testNoSamAdapter() throws Exception {
                 String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoSamAdapter.kt");
diff --git a/idea/testData/checker/SupertypeListChecks.kt b/idea/testData/checker/SupertypeListChecks.kt
index 9755d5016f9..0eb8dd60c24 100644
--- a/idea/testData/checker/SupertypeListChecks.kt
+++ b/idea/testData/checker/SupertypeListChecks.kt
@@ -24,11 +24,11 @@ interface T2<T> {}
 interface Test<error>()</error> {
 }
 
-interface Test1 : <warning>C2</warning><error>()</error> {}
+interface Test1 : <error>C2</error><error>()</error> {}
 
-interface Test2 : <warning>C2</warning> {}
+interface Test2 : <error>C2</error> {}
 
-interface Test3 : <warning>C2</warning>, <error>C3</error> {}
+interface Test3 : <error>C2</error>, <error>C3</error> {}
 
 interface Test4 : T1 {}
 
diff --git a/idea/testData/checker/TraitSupertypeList.kt b/idea/testData/checker/TraitSupertypeList.kt
index 4d0411e6305..505131f1cf9 100644
--- a/idea/testData/checker/TraitSupertypeList.kt
+++ b/idea/testData/checker/TraitSupertypeList.kt
@@ -1,10 +1,10 @@
 open class bar()
 
-interface Foo<error>()</error> : <warning>bar</warning><error>()</error>, <error><error>bar</error></error>, <error><error>bar</error></error> {
+interface Foo<error>()</error> : <error>bar</error><error>()</error>, <error><error>bar</error></error>, <error><error>bar</error></error> {
 }
 
-interface Foo2 : <warning>bar</warning>, Foo {
+interface Foo2 : <error>bar</error>, Foo {
 }
 
 open class Foo1() : bar(), <error>bar</error>, Foo, <error>Foo</error>() {}
-open class Foo12 : bar(), <error>bar</error> {}
\ No newline at end of file
+open class Foo12 : bar(), <error>bar</error> {}
diff --git a/idea/testData/checker/unmetTraitRequirements.kt b/idea/testData/checker/unmetTraitRequirements.kt
deleted file mode 100644
index 9973da8408c..00000000000
--- a/idea/testData/checker/unmetTraitRequirements.kt
+++ /dev/null
@@ -1,15 +0,0 @@
-open class Base {
-}
-
-interface Derived: <warning>Base</warning> {
-    fun foo() {
-        f1(this@Derived)
-    }
-}
-
-<error>class DerivedImpl</error>(): Derived {}
-<error>object ObjectImpl</error>: Derived {}
-
-fun f1(b: Base) = b
-
-// KT-3006
\ No newline at end of file
diff --git a/idea/tests/org/jetbrains/kotlin/checkers/JetPsiCheckerTestGenerated.java b/idea/tests/org/jetbrains/kotlin/checkers/JetPsiCheckerTestGenerated.java
index 58c8a0ae17b..46057ccce06 100644
--- a/idea/tests/org/jetbrains/kotlin/checkers/JetPsiCheckerTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/checkers/JetPsiCheckerTestGenerated.java
@@ -325,12 +325,6 @@ public class JetPsiCheckerTestGenerated extends AbstractJetPsiCheckerTest {
             doTest(fileName);
         }
 
-        @TestMetadata("unmetTraitRequirements.kt")
-        public void testUnmetTraitRequirements() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("idea/testData/checker/unmetTraitRequirements.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("UnreachableCode.kt")
         public void testUnreachableCode() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("idea/testData/checker/UnreachableCode.kt");
diff --git a/idea/tests/org/jetbrains/kotlin/idea/stubs/ResolveByStubTestGenerated.java b/idea/tests/org/jetbrains/kotlin/idea/stubs/ResolveByStubTestGenerated.java
index cceda1b65f6..6d52f481654 100644
--- a/idea/tests/org/jetbrains/kotlin/idea/stubs/ResolveByStubTestGenerated.java
+++ b/idea/tests/org/jetbrains/kotlin/idea/stubs/ResolveByStubTestGenerated.java
@@ -2140,12 +2140,6 @@ public class ResolveByStubTestGenerated extends AbstractResolveByStubTest {
             doTest(fileName);
         }
 
-        @TestMetadata("NoDelegationForFunctionInheritedFromTraitSuperClass.kt")
-        public void testNoDelegationForFunctionInheritedFromTraitSuperClass() throws Exception {
-            String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoDelegationForFunctionInheritedFromTraitSuperClass.kt");
-            doTest(fileName);
-        }
-
         @TestMetadata("NoSamAdapter.kt")
         public void testNoSamAdapter() throws Exception {
             String fileName = JetTestUtils.navigationMetadata("compiler/testData/loadJava/compiledKotlin/fun/NoSamAdapter.kt");
diff --git a/js/js.libraries/src/core/htmlDom.kt b/js/js.libraries/src/core/htmlDom.kt
index 8a91ec63e4a..67235f6d904 100644
--- a/js/js.libraries/src/core/htmlDom.kt
+++ b/js/js.libraries/src/core/htmlDom.kt
@@ -187,7 +187,7 @@ public native trait HTMLOptionsCollection {
 }
 
 deprecated("Use declarations from org.w3c.dom instead")
-public native trait HTMLDocument : Document {
+public native class HTMLDocument : Document() {
     public native fun open(): Unit
     public native fun write(text: String): Unit
     public native fun writeln(text: String): Unit
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BridgeTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BridgeTestGenerated.java
index 7e64395faa7..9a917d98902 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BridgeTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/BridgeTestGenerated.java
@@ -101,12 +101,6 @@ public class BridgeTestGenerated extends AbstractBridgeTest {
         doTest(fileName);
     }
 
-    @TestMetadata("fakeOverrideInTraitWithRequiredFromTraitImpl.kt")
-    public void testFakeOverrideInTraitWithRequiredFromTraitImpl() throws Exception {
-        String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt");
-        doTest(fileName);
-    }
-
     @TestMetadata("fakeOverrideOfPropertySetterInTraitImpl.kt")
     public void testFakeOverrideOfPropertySetterInTraitImpl() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/fakeOverrideOfPropertySetterInTraitImpl.kt");
@@ -287,12 +281,6 @@ public class BridgeTestGenerated extends AbstractBridgeTest {
         doTest(fileName);
     }
 
-    @TestMetadata("traitWithRequiredCovariantOverride.kt")
-    public void testTraitWithRequiredCovariantOverride() throws Exception {
-        String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt");
-        doTest(fileName);
-    }
-
     @TestMetadata("twoParentsWithDifferentMethodsTwoBridges.kt")
     public void testTwoParentsWithDifferentMethodsTwoBridges() throws Exception {
         String fileName = JetTestUtils.navigationMetadata("compiler/testData/codegen/box/bridges/twoParentsWithDifferentMethodsTwoBridges.kt");
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/ClassInheritanceTest.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/ClassInheritanceTest.java
index cd829431b1c..9ad8ac0e555 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/ClassInheritanceTest.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/ClassInheritanceTest.java
@@ -44,10 +44,6 @@ public final class ClassInheritanceTest extends SingleFileTranslationTest {
         checkFooBoxIsOk();
     }
 
-    public void testCrazyInheritance() throws Exception {
-        checkFooBoxIsOk();
-    }
-
     public void testValOverride() throws Exception {
         fooBoxTest();
     }
diff --git a/js/js.translator/testData/examples/cases/diamondInheritance.kt b/js/js.translator/testData/examples/cases/diamondInheritance.kt
deleted file mode 100644
index b0ce0447a44..00000000000
--- a/js/js.translator/testData/examples/cases/diamondInheritance.kt
+++ /dev/null
@@ -1,26 +0,0 @@
-// Changed when traits were introduced. May not make sense any more
-
-open class Base() {
-    public var v: Int = 0
-}
-
-open class Left() : Base() {
-}
-trait Right : Base {
-}
-
-class D() : Left(), Right
-
-fun vl(l: Left): Int = l.v
-fun vr(r: Right): Int = r.v
-
-fun box(): String {
-    val d = D()
-    d.v = 42
-
-    if (d.v != 42) return "Fail #1"
-    if (vl(d) != 42) return "Fail #2"
-    if (vr(d) != 42) return "Fail #3"
-
-    return "OK"
-}
\ No newline at end of file
diff --git a/js/js.translator/testData/inheritance/cases/crazyInheritance.kt b/js/js.translator/testData/inheritance/cases/crazyInheritance.kt
deleted file mode 100644
index b80fc0f0302..00000000000
--- a/js/js.translator/testData/inheritance/cases/crazyInheritance.kt
+++ /dev/null
@@ -1,56 +0,0 @@
-package foo
-
-open class A {
-    open fun f1() = "A1"
-    open fun f2() = "A2"
-    open fun f3() = "A3"
-    open fun f4() = "A4"
-
-    fun getSum(): String {
-        return "${f1()}|${f2()}|${f3()}|${f4()}"
-    }
-}
-
-trait T : A {
-    override fun f1() = "T1"
-    override fun f2() = "T2"
-}
-
-trait B : A {
-    override fun f1() = "B1"
-    override fun f3() = "B3"
-}
-
-trait N : B, T {
-    override fun f1() = "N1"
-}
-
-trait X {
-    fun f4() = "X4"
-}
-
-class C : A(), N, X {
-    override fun f4() = "C4"
-}
-
-fun box(): String {
-    val a = A()
-    val t = object : T, A() {
-    }
-    val b = object : B, A() {
-    }
-    val n = object : N, A() {
-    }
-    val x = object : X {
-    }
-    val c = C()
-
-    if (a.getSum() != "A1|A2|A3|A4") return "Bad a.getSum(), it: ${a.getSum()}"
-    if (t.getSum() != "T1|T2|A3|A4") return "Bad t.getSum(), it: ${t.getSum()}"
-    if (b.getSum() != "B1|A2|B3|A4") return "Bad b.getSum(), it: ${b.getSum()}"
-    if (n.getSum() != "N1|T2|B3|A4") return "Bad n.getSum(), it: ${n.getSum()}"
-    if (c.getSum() != "N1|T2|B3|C4") return "Bad c.getSum(), it: ${c.getSum()}"
-
-    if (x.f4() != "X4") return "Bad x.f4(), it: ${x.f4()}"
-    return "OK"
-}
\ No newline at end of file