From fccfe96854ca59b74fb3cd13a2db9cff005510ed Mon Sep 17 00:00:00 2001
From: cpovirk <cpovirk@google.com>
Date: Wed, 24 Jan 2024 08:00:49 -0800
Subject: [PATCH] Make J2CL super-source'd classes pass nullness checking.

RELNOTES=n/a
PiperOrigin-RevId: 601121536
---
 .../com/google/common/collect/DescendingMultiset.java  |  1 +
 .../google/common/collect/ForwardingImmutableMap.java  |  4 +++-
 .../com/google/common/collect/ImmutableSortedMap.java  |  6 ++++--
 .../com/google/common/collect/ImmutableSortedSet.java  | 10 +++++++++-
 4 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/DescendingMultiset.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/DescendingMultiset.java
index aaecc2d166ca..a5924b88fd3b 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/DescendingMultiset.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/DescendingMultiset.java
@@ -150,6 +150,7 @@ public Iterator<E> iterator() {
   }
 
   @Override
+  @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
   public <T extends @Nullable Object> T[] toArray(T[] array) {
     return standardToArray(array);
   }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
index 8fbed96f069e..1b13ed3ea151 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ForwardingImmutableMap.java
@@ -92,12 +92,14 @@ public boolean contains(@Nullable Object object) {
           }
 
           @Override
+          @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
           public <T extends @Nullable Object> T[] toArray(T[] array) {
             T[] result = super.toArray(array);
             if (size() < result.length) {
               // It works around a GWT bug where elements after last is not
               // properly null'ed.
-              result[size()] = null;
+              @Nullable Object[] unsoundlyCovariantArray = result;
+              unsoundlyCovariantArray[size()] = null;
             }
             return result;
           }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
index e6f4ce6f20a3..cc43b88a4668 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedMap.java
@@ -484,7 +484,9 @@ public ImmutableSortedMap<K, V> tailMap(K fromKey) {
     return newView(sortedDelegate.tailMap(fromKey));
   }
 
-  public ImmutableSortedMap<K, V> tailMap(K fromKey, boolean inclusive) {
+  public ImmutableSortedMap<K, V> tailMap(K fromKeyParam, boolean inclusive) {
+    // Declare a "true" local variable so that the Checker Framework will infer nullness.
+    K fromKey = fromKeyParam;
     checkNotNull(fromKey);
     if (!inclusive) {
       fromKey = higher(fromKey);
@@ -522,6 +524,6 @@ private static <K, V> SortedMap<K, V> newModifiableDelegate(Comparator<? super K
   }
 
   private static <E> Comparator<@Nullable E> nullAccepting(Comparator<E> comparator) {
-    return Ordering.from(comparator).nullsFirst();
+    return Ordering.from(comparator).<E>nullsFirst();
   }
 }
diff --git a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
index 14fae8b9c7a2..1f6e879b43ab 100644
--- a/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
+++ b/guava-gwt/src-super/com/google/common/collect/super/com/google/common/collect/ImmutableSortedSet.java
@@ -262,10 +262,18 @@ public UnmodifiableIterator<E> iterator() {
 
   @Override
   public Object[] toArray() {
-    return ObjectArrays.toArrayImpl(this);
+    /*
+     * ObjectArrays.toArrayImpl returns `@Nullable Object[]` rather than `Object[]` but only because
+     * it can be used with collections that may contain null. This collection is a collection of
+     * non-null elements, so we can treat it as a plain `Object[]`.
+     */
+    @SuppressWarnings("nullness")
+    Object[] result = ObjectArrays.toArrayImpl(this);
+    return result;
   }
 
   @Override
+  @SuppressWarnings("nullness") // b/192354773 in our checker affects toArray declarations
   public <T extends @Nullable Object> T[] toArray(T[] other) {
     return ObjectArrays.toArrayImpl(this, other);
   }