Transform CharSequence.length to property

compiler/testData/diagnostics/tests/cast/neverSucceeds/MappedSubtypes.txt

@@ -14,10 +14,10 @@ public final class JSub : java.lang.CharSequence {
 
 public final class Sub : kotlin.CharSequence {
     public constructor Sub()
+    public abstract override /*1*/ /*fake_override*/ val length: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public abstract override /*1*/ /*fake_override*/ fun get(/*0*/ index: kotlin.Int): kotlin.Char
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public abstract override /*1*/ /*fake_override*/ fun length(): kotlin.Int
     public abstract override /*1*/ /*fake_override*/ fun subSequence(/*0*/ start: kotlin.Int, /*1*/ end: kotlin.Int): kotlin.CharSequence
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }

compiler/testData/diagnostics/tests/j+k/collectionOverrides/getCharSequence.kt

@@ -1,17 +1,20 @@
 // FILE: A.java
 abstract public class A implements CharSequence {
     public char charAt(int x) { }
+    public int length() { return 1; }
 }
 
 // FILE: C.java
 abstract public class C implements CharSequence {
     public char get(int x) { }
+    public int length() { return 1; }
 }
 
 // FILE: main.kt
 
 abstract class B : A(), CharSequence {
     override operator fun get(index: Int) = '1'
+    override val length: Int get() = 1
 }
 
 fun main(a: A, b: B, c: C) {
@@ -22,4 +25,6 @@ fun main(a: A, b: B, c: C) {
     a.get(0)
     b.get(0)
     c.get(0)
+
+    a.length + b.length + c.length
 }

compiler/testData/diagnostics/tests/j+k/collectionOverrides/getCharSequence.txt

@@ -4,30 +4,30 @@ public fun main(/*0*/ a: A, /*1*/ b: B, /*2*/ c: C): kotlin.Unit
 
 public abstract class A : kotlin.CharSequence {
     public constructor A()
+    public open override /*1*/ val length: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ fun get(/*0*/ x: kotlin.Int): kotlin.Char
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public abstract override /*1*/ /*fake_override*/ fun length(): kotlin.Int
     public abstract override /*1*/ /*fake_override*/ fun subSequence(/*0*/ start: kotlin.Int, /*1*/ end: kotlin.Int): kotlin.CharSequence
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
 public abstract class B : A, kotlin.CharSequence {
     public constructor B()
+    public open override /*2*/ val length: kotlin.Int
     public open override /*2*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*2*/ fun get(/*0*/ index: kotlin.Int): kotlin.Char
     public open override /*2*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public abstract override /*2*/ /*fake_override*/ fun length(): kotlin.Int
     public abstract override /*2*/ /*fake_override*/ fun subSequence(/*0*/ start: kotlin.Int, /*1*/ end: kotlin.Int): kotlin.CharSequence
     public open override /*2*/ /*fake_override*/ fun toString(): kotlin.String
 }
 
 public abstract class C : kotlin.CharSequence {
     public constructor C()
+    public open override /*1*/ val length: kotlin.Int
     public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
     public open override /*1*/ fun get(/*0*/ index: kotlin.Int): kotlin.Char
     public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
-    public abstract override /*1*/ /*fake_override*/ fun length(): kotlin.Int
     public abstract override /*1*/ /*fake_override*/ fun subSequence(/*0*/ start: kotlin.Int, /*1*/ end: kotlin.Int): kotlin.CharSequence
     public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
 }