Make mutation methods in AbstractMutable-collections abstract rather than implement them unsupported.

libraries/stdlib/src/kotlin/collections/AbstractMutableCollection.kt

@@ -0,0 +1,8 @@
+@file:JvmVersion
+package kotlin.collections
+
+import java.util.AbstractCollection
+
+public abstract class AbstractMutableCollection<E> protected constructor() : AbstractCollection<E>() {
+    abstract override fun add(element: E): Boolean
+}

libraries/stdlib/src/kotlin/collections/AbstractMutableList.kt

@@ -0,0 +1,10 @@
+@file:JvmVersion
+package kotlin.collections
+
+import java.util.AbstractList
+
+public abstract class AbstractMutableList<E> protected constructor() : AbstractList<E>() {
+    abstract override fun set(index: Int, element: E): E
+    abstract override fun removeAt(index: Int): E
+    abstract override fun add(index: Int, element: E)
+}

libraries/stdlib/src/kotlin/collections/AbstractMutableMap.kt

@@ -0,0 +1,8 @@
+@file:JvmVersion
+package kotlin.collections
+
+import java.util.AbstractMap
+
+public abstract class AbstractMutableMap<K, V> protected constructor() : AbstractMap<K, V>() {
+    abstract override fun put(key: K, value: V): V?
+}

libraries/stdlib/src/kotlin/collections/AbstractMutableSet.kt

@@ -0,0 +1,8 @@
+@file:JvmVersion
+package kotlin.collections
+
+import java.util.AbstractSet
+
+public abstract class AbstractMutableSet<E> protected constructor() : AbstractSet<E>() {
+    // nothing to make abstract, maybe leave it typealias then?
+}

libraries/stdlib/src/kotlin/collections/TypeAliases.kt

@@ -1,7 +0,0 @@
-@file:JvmVersion
-package kotlin.collections
-
-public typealias AbstractMutableCollection<E> = java.util.AbstractCollection<E>
-public typealias AbstractMutableList<E> = java.util.AbstractList<E>
-public typealias AbstractMutableSet<E> = java.util.AbstractSet<E>
-public typealias AbstractMutableMap<K, V> = java.util.AbstractMap<K, V>

libraries/tools/binary-compatibility-validator/reference-public-api/kotlin-stdlib.txt

@@ -149,6 +149,42 @@ public abstract class kotlin/collections/AbstractMap : java/util/Map, kotlin/jvm
 	public final fun values ()Ljava/util/Collection;
 }
 
+public abstract class kotlin/collections/AbstractMutableCollection : java/util/AbstractCollection {
+	protected fun <init> ()V
+	public abstract fun add (Ljava/lang/Object;)Z
+	public abstract fun getSize ()I
+	public final fun size ()I
+}
+
+public abstract class kotlin/collections/AbstractMutableList : java/util/AbstractList {
+	protected fun <init> ()V
+	public abstract fun add (ILjava/lang/Object;)V
+	public abstract fun getSize ()I
+	public final fun remove (I)Ljava/lang/Object;
+	public abstract fun removeAt (I)Ljava/lang/Object;
+	public abstract fun set (ILjava/lang/Object;)Ljava/lang/Object;
+	public final fun size ()I
+}
+
+public abstract class kotlin/collections/AbstractMutableMap : java/util/AbstractMap {
+	protected fun <init> ()V
+	public final fun entrySet ()Ljava/util/Set;
+	public abstract fun getEntries ()Ljava/util/Set;
+	public fun getKeys ()Ljava/util/Set;
+	public fun getSize ()I
+	public fun getValues ()Ljava/util/Collection;
+	public final fun keySet ()Ljava/util/Set;
+	public abstract fun put (Ljava/lang/Object;Ljava/lang/Object;)Ljava/lang/Object;
+	public final fun size ()I
+	public final fun values ()Ljava/util/Collection;
+}
+
+public abstract class kotlin/collections/AbstractMutableSet : java/util/AbstractSet {
+	protected fun <init> ()V
+	public abstract fun getSize ()I
+	public final fun size ()I
+}
+
 public abstract class kotlin/collections/AbstractSet : kotlin/collections/AbstractCollection, java/util/Set, kotlin/jvm/internal/markers/KMappedMarker {
 	public static final field Companion Lkotlin/collections/AbstractSet$Companion;
 	protected fun <init> ()V