[utils] Smart/F/SortedList: annotate classes with Kotlin @PurelyImplements to ensure nullability is correctly handled by Kotlin compiler.

(cherry picked from commit b144211ca6d9e8a47b883dd2e799c766d950f033)

IJ-CR-155942

GitOrigin-RevId: b6393e6d5552d618962dca8f738bf3beb7593c97

platform/script-debugger/backend/src/debugger/sourcemap/SourceMapDecoder.kt

@@ -157,7 +157,7 @@ private fun parseMap(reader: JsonReaderEx): SourceMapDataImpl? {
         }
         reader.beginArray()
         if (reader.peek() != JsonToken.END_ARRAY) {
-          sourcesContent = SmartList<String>()
+          sourcesContent = SmartList<String?>()
           do {
             if (reader.peek() == JsonToken.STRING) {
               sourcesContent.add(StringUtilRt.convertLineSeparators(reader.nextString()))

platform/util/base/src/com/intellij/util/SmartList.java

@@ -2,6 +2,7 @@
 package com.intellij.util;
 
 import com.intellij.ReviseWhenPortedToJDK;
+import kotlin.jvm.PurelyImplements;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.*;
@@ -14,6 +15,7 @@ import java.util.function.Consumer;
  * The tradeoff is the following: This list is slower than {@link ArrayList} but occupies less memory in case of exactly 1 element.
  * Please use it only if your code contains many 1-element lists outside very hot loops.
  */
+@PurelyImplements("kotlin.collections.MutableList")
 public class SmartList<E> extends AbstractList<E> implements RandomAccess {
   private int mySize;
   private Object myElem; // null if mySize==0, (E)elem if mySize==1, Object[] if mySize>=2

platform/util/base/src/com/intellij/util/containers/FList.java

@@ -2,6 +2,7 @@
 package com.intellij.util.containers;
 
 import com.intellij.openapi.util.Comparing;
+import kotlin.jvm.PurelyImplements;
 import org.jetbrains.annotations.NotNull;
 
 import java.util.AbstractList;
@@ -11,6 +12,7 @@ import java.util.NoSuchElementException;
 /**
  * Immutable list in functional style
  */
+@PurelyImplements("kotlin.collections.MutableList")
 public final class FList<E> extends AbstractList<E> {
   private static final FList<?> EMPTY_LIST = new FList<>(null, null, 0);
   private final E myHead;
@@ -140,7 +142,7 @@ public final class FList<E> extends AbstractList<E> {
   public static <E> FList<E> singleton(@NotNull E elem) {
     return FList.<E>emptyList().prepend(elem);
   }
-  
+
   /**
    * Creates an FList object with the elements of the given sequence in the reversed order, i.e. the last element of {@code from} will be the result's {@link #getHead()}
    */

platform/util/src/com/intellij/util/containers/SortedList.java

@@ -2,11 +2,13 @@
 package com.intellij.util.containers;
 
 import com.intellij.util.SmartList;
+import kotlin.jvm.PurelyImplements;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Unmodifiable;
 
 import java.util.*;
 
+@PurelyImplements("kotlin.collections.MutableList")
 public final class SortedList<T> extends AbstractList<T>{
   private final SortedMap<T, List<T>> myMap;
   private final Comparator<? super T> myComparator;