Add @CheckReturnValue to Truth's package-info.java.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=113490153

core/pom.xml

@@ -60,6 +60,11 @@
       <version>0.8</version>
       <scope>test</scope>
     </dependency>
+    <dependency>
+      <groupId>com.google.errorprone</groupId>
+      <artifactId>error_prone_annotations</artifactId>
+      <version>2.0.8</version>
+    </dependency>
   </dependencies>
   <build>
     <resources>

core/src/main/java/com/google/common/truth/AbstractVerb.java

@@ -18,7 +18,6 @@
 import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.truth.StringUtil.format;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 public abstract class AbstractVerb<T extends AbstractVerb<T>> {
@@ -56,7 +55,6 @@ public void fail(@Nullable String format, Object... args) {
    * @return A custom verb which will show the descriptive message along with the normal failure
    *     text.
    */
-  @CheckReturnValue
   public abstract T withFailureMessage(@Nullable String failureMessage);
 
   @Nullable
@@ -93,7 +91,6 @@ public DelegatedVerb(FailureStrategy failureStrategy, SubjectFactory<S, T> facto
       this.failureStrategy = checkNotNull(failureStrategy);
     }
 
-    @CheckReturnValue
     public S that(T target) {
       return factory.getSubject(failureStrategy, target);
     }

core/src/main/java/com/google/common/truth/DoubleSubject.java

@@ -22,7 +22,6 @@
 import static com.google.common.truth.MathUtil.notEqualWithinTolerance;
 import static java.lang.Double.doubleToLongBits;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
@@ -94,7 +93,6 @@ public int hashCode() {
    *     allowed by the check, which must be a non-negative finite value, i.e. not
    *     {@link Double#NaN}, {@link Double#POSITIVE_INFINITY}, or negative, including {@code -0.0}
    */
-  @CheckReturnValue
   public TolerantDoubleComparison isWithin(final double tolerance) {
     return new TolerantDoubleComparison() {
       @Override
@@ -130,7 +128,6 @@ public void of(double expected) {
    *     allowed by the check, which must be a non-negative finite value, i.e. not
    *     {@code Double.NaN}, {@code Double.POSITIVE_INFINITY}, or negative, including {@code -0.0}
    */
-  @CheckReturnValue
   public TolerantDoubleComparison isNotWithin(final double tolerance) {
     return new TolerantDoubleComparison() {
       @Override

core/src/main/java/com/google/common/truth/FloatSubject.java

@@ -22,15 +22,13 @@
 import static com.google.common.truth.MathUtil.notEqualWithinTolerance;
 import static java.lang.Float.floatToIntBits;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
  * Propositions for {@link Float} subjects.
  *
  * @author Kurt Alfred Kluever
  */
-@CheckReturnValue
 public final class FloatSubject extends ComparableSubject<FloatSubject, Float> {
   private static final int NEG_ZERO_BITS = floatToIntBits(-0.0f);
 

core/src/main/java/com/google/common/truth/IterableSubject.java

@@ -30,6 +30,7 @@
 import com.google.common.collect.Multiset.Entry;
 import com.google.common.collect.Ordering;
 import com.google.common.collect.Sets;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 
 import java.util.ArrayList;
 import java.util.Collection;
@@ -55,6 +56,7 @@ protected IterableSubject(FailureStrategy failureStrategy, @Nullable Iterable<?>
    * representations of the subject.
    */
   @Override
+  @CanIgnoreReturnValue
   public IterableSubject named(String name) {
     super.named(name);
     return this;
@@ -174,6 +176,7 @@ private void containsAny(String failVerb, Iterable<?> expected) {
    * <p>Callers may optionally chain an {@code inOrder()} call if its expected
    * contents must be contained in the given order.
    */
+  @CanIgnoreReturnValue
   public final Ordered containsAllOf(
       @Nullable Object first, @Nullable Object second, @Nullable Object... rest) {
     return containsAll("contains all of", accumulate(first, second, rest));
@@ -187,6 +190,7 @@ public final Ordered containsAllOf(
    * <p>Callers may optionally chain an {@code inOrder()} call if its expected
    * contents must be contained in the given order.
    */
+  @CanIgnoreReturnValue
   public final Ordered containsAllIn(Iterable<?> expected) {
     return containsAll("contains all elements in", expected);
   }
@@ -242,6 +246,7 @@ private static void moveElements(List<?> input, Collection<Object> output, int m
    * <p>Callers may optionally chain an {@code inOrder()} call if its expected
    * contents must be contained in the given order.
    */
+  @CanIgnoreReturnValue
   public final Ordered containsExactly(@Nullable Object... varargs) {
     List<Object> expected = (varargs == null) ? Lists.newArrayList((Object) null) : asList(varargs);
     return containsExactly(
@@ -260,6 +265,7 @@ public final Ordered containsExactly(@Nullable Object... varargs) {
    * <p>Callers may optionally chain an {@code inOrder()} call if its expected
    * contents must be contained in the given order.
    */
+  @CanIgnoreReturnValue
   public final Ordered containsExactlyElementsIn(Iterable<?> expected) {
     return containsExactly("contains exactly", expected, false);
   }

core/src/main/java/com/google/common/truth/MapSubject.java

@@ -22,6 +22,7 @@
 import com.google.common.collect.MapDifference;
 import com.google.common.collect.Maps;
 import com.google.common.collect.Multiset;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 
 import java.util.Map;
 import java.util.Map.Entry;
@@ -42,6 +43,7 @@ public class MapSubject extends Subject<MapSubject, Map<?, ?>> {
   /**
    * Fails if the subject is not equal to the given object.
    */
+  @Override
   public void isEqualTo(@Nullable Object other) {
     if (!Objects.equal(getSubject(), other)) {
       if (other instanceof Map) {
@@ -140,6 +142,7 @@ public void doesNotContainEntry(@Nullable Object key, @Nullable Object value) {
   /**
    * Fails if the map is not empty.
    */
+  @CanIgnoreReturnValue
   public Ordered containsExactly() {
     return check().that(getSubject().entrySet()).containsExactly();
   }
@@ -151,6 +154,7 @@ public Ordered containsExactly() {
    * key/value pairs at compile time. Please make sure you provide varargs in key/value pairs!
    */
   // TODO(b/25744307): Can we add an error-prone check that rest.length % 2 == 0?
+  @CanIgnoreReturnValue
   public Ordered containsExactly(@Nullable Object k0, @Nullable Object v0, Object... rest) {
     checkArgument(
         rest.length % 2 == 0,
@@ -177,6 +181,7 @@ public Ordered containsExactly(@Nullable Object k0, @Nullable Object v0, Object.
   /**
    * Fails if the map does not contain exactly the given set of entries in the given map.
    */
+  @CanIgnoreReturnValue
   public Ordered containsExactlyEntriesIn(Map<?, ?> expectedMap) {
     return check().that(getSubject().entrySet()).containsExactlyElementsIn(expectedMap.entrySet());
   }

core/src/main/java/com/google/common/truth/MultimapSubject.java

@@ -28,14 +28,14 @@
 import com.google.common.collect.Multimap;
 import com.google.common.collect.SetMultimap;
 import com.google.common.collect.Sets;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.LinkedHashSet;
 import java.util.List;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
@@ -131,7 +131,6 @@ public void doesNotContainEntry(@Nullable Object key, @Nullable Object value) {
    * <p>This method performs no checks on its own and cannot cause test failures.  Subsequent
    * assertions must be chained onto this method call to test properties of the Multimap.
    */
-  @CheckReturnValue
   public IterableSubject valuesForKey(@Nullable Object key) {
     return new IterableValuesForKey(failureStrategy, this, key);
   }
@@ -176,6 +175,7 @@ public void isEqualTo(@Nullable Object other) {
    * that the two Multimaps iterate fully in the same order.  That is, their key sets iterate
    * in the same order, and the value collections for each key iterate in the same order.
    */
+  @CanIgnoreReturnValue
   public Ordered containsExactlyEntriesIn(Multimap<?, ?> expectedMultimap) {
     checkNotNull(expectedMultimap, "expectedMultimap");
     return containsExactly("contains exactly", expectedMultimap);
@@ -185,6 +185,7 @@ public Ordered containsExactlyEntriesIn(Multimap<?, ?> expectedMultimap) {
    * @deprecated Use {@link #containsExactlyEntriesIn} instead.
    */
   @Deprecated
+  @CanIgnoreReturnValue
   public Ordered containsExactly(Multimap<?, ?> expectedMultimap) {
     return containsExactlyEntriesIn(expectedMultimap);
   }

core/src/main/java/com/google/common/truth/ObjectArraySubject.java

@@ -32,15 +32,13 @@
 import java.util.Arrays;
 import java.util.List;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
  * A Subject to handle testing propositions for {@code Object[]} and more generically {@code T[]}.
  *
  * @author Christian Gruber
  */
-@CheckReturnValue
 public class ObjectArraySubject<T> extends AbstractArraySubject<ObjectArraySubject<T>, T[]> {
   private final String typeName;
   private final int numberOfDimensions;

core/src/main/java/com/google/common/truth/PrimitiveDoubleArraySubject.java

@@ -27,7 +27,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
@@ -39,7 +38,6 @@
  *
  * @author Christian Gruber (cgruber@israfil.net)
  */
-@CheckReturnValue
 public class PrimitiveDoubleArraySubject
     extends AbstractArraySubject<PrimitiveDoubleArraySubject, double[]> {
   PrimitiveDoubleArraySubject(FailureStrategy failureStrategy, @Nullable double[] o) {

core/src/main/java/com/google/common/truth/PrimitiveFloatArraySubject.java

@@ -27,7 +27,6 @@
 import java.util.ArrayList;
 import java.util.List;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
@@ -39,7 +38,6 @@
  *
  * @author Christian Gruber (cgruber@israfil.net)
  */
-@CheckReturnValue
 public class PrimitiveFloatArraySubject
     extends AbstractArraySubject<PrimitiveFloatArraySubject, float[]> {
   PrimitiveFloatArraySubject(FailureStrategy failureStrategy, @Nullable float[] o) {

core/src/main/java/com/google/common/truth/Subject.java

@@ -22,6 +22,7 @@
 import com.google.common.base.Objects;
 import com.google.common.base.Predicates;
 import com.google.common.collect.Iterables;
+import com.google.errorprone.annotations.CanIgnoreReturnValue;
 
 import java.util.List;
 
@@ -53,6 +54,7 @@ protected String internalCustomName() {
    * representations of the subject.
    */
   @SuppressWarnings("unchecked")
+  @CanIgnoreReturnValue
   public S named(String name) {
     // TODO: use check().withFailureMessage... here?
     this.customName = checkNotNull(name, "Name passed to named() cannot be null.");

core/src/main/java/com/google/common/truth/TestVerb.java

@@ -28,10 +28,8 @@
 import java.math.BigDecimal;
 import java.util.Map;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
-@CheckReturnValue
 public class TestVerb extends AbstractVerb<TestVerb> {
   private static final Object[] EMPTY_ARGS = new Object[0];
   @Nullable private final String format;

core/src/main/java/com/google/common/truth/Truth.gwt.xml

@@ -1,29 +1,27 @@
+<?xml version="1.0" encoding="utf-8"?>
 <!-- semi-autogenerated module descriptor -->
 <module>
-<source path="">
-  <!-- Hack to keep collect from hiding collect.testing supersource: -->
-  <exclude name="**/testing/**"/>
-</source>
-
-<!--
-     We used to set this only for packages that had manual supersource.
-     That worked everywhere that I know of except for one place:
-     when running the GWT util.concurrent tests under Guava.
-     The problem is that GWT responds poorly to two .gwt.xml files in the same Java package:
-     http://goo.gl/CO7dLB
-     The summary is that it ignores one file in favor of the other.
-     util.concurrent, like nearly all our packages, has two .gwt.xml files: one for prod and one for tests.
-     util.concurrent, unlike our other packages, has, as of this writing, test supersource but no prod supersource.
-     GWT happens to use the prod .gwt.xml, so it looks for no supersource for tests, either.
-     This causes it to fail to find AtomicLongMapTest.
-     Our workaround is to tell GWT that util.concurrent and all other packages have prod supersource, even if they have none.
-     GWT is happy to ignore us when we specify a nonexistent path.
-     (I hope that this workaround does not cause its own problems in the future.)
--->
-<super-source path="super"/>
-<inherits name="com.google.common.annotations.Annotations"/>
-<inherits name="com.google.common.base.Base"/>
-<inherits name="com.google.common.collect.Collect"/>
-<inherits name="com.google.common.primitives.Primitives"/>
-<inherits name="com.google.gwt.core.Core"/>
+
+  <source path="">
+
+    <!-- Hack to keep collect from hiding collect.testing supersource: -->
+
+    <exclude name="**/testing/**"/>
+
+  </source>
+
+  <!-- We used to set this only for packages that had manual supersource. That worked everywhere that I know of except for one place: when running the GWT util.concurrent tests under Guava. The problem is that GWT responds poorly to two .gwt.xml files in the same Java package: http://goo.gl/CO7dLB The summary is that it ignores one file in favor of the other. util.concurrent, like nearly all our packages, has two .gwt.xml files: one for prod and one for tests. util.concurrent, unlike our other packages, has, as of this writing, test supersource but no prod supersource. GWT happens to use the prod .gwt.xml, so it looks for no supersource for tests, either. This causes it to fail to find AtomicLongMapTest. Our workaround is to tell GWT that util.concurrent and all other packages have prod supersource, even if they have none. GWT is happy to ignore us when we specify a nonexistent path. (I hope that this workaround does not cause its own problems in the future.) -->
+
+  <super-source path="super"/>
+
+  <inherits name="com.google.common.annotations.Annotations"/>
+
+  <inherits name="com.google.common.base.Base"/>
+
+  <inherits name="com.google.common.collect.Collect"/>
+
+  <inherits name="com.google.common.primitives.Primitives"/>
+
+  <inherits name="com.google.gwt.core.Core"/>
+
 </module>

core/src/main/java/com/google/common/truth/Truth.java

@@ -27,7 +27,6 @@
 import java.math.BigDecimal;
 import java.util.Map;
 
-import javax.annotation.CheckReturnValue;
 import javax.annotation.Nullable;
 
 /**
@@ -67,7 +66,6 @@
  * @author David Saff
  * @author Christian Gruber (cgruber@israfil.net)
  */
-@CheckReturnValue
 public final class Truth {
   private Truth() {}
 

core/src/main/java/com/google/common/truth/package-info.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2016 Google, Inc.
+ *
+ * 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.
+ */
+
+/**
+ * Truth is an open source, fluent testing framework for Java that is designed to make your
+ * test assertions and failure messages more readable.
+ *
+ * <p>This package is a part of the open-source
+ * <a href="http://github.com/google/truth">Truth</a> library.
+ */
+@CheckReturnValue
+@ParametersAreNonnullByDefault
+package com.google.common.truth;
+
+import javax.annotation.CheckReturnValue;
+import javax.annotation.ParametersAreNonnullByDefault;

core/src/test/java/com/google/common/truth/SubjectTest.java

@@ -670,7 +670,7 @@ public void throwableHasInitedCause() {
   @Test
   public void equalsThrowsUSOE() {
     try {
-      assertThat(5).equals(5);
+      boolean unused = assertThat(5).equals(5);
     } catch (UnsupportedOperationException expected) {
       assertThat(expected)
           .hasMessage("If you meant to test object equality, use .isEqualTo(other) instead.");
@@ -682,7 +682,7 @@ public void equalsThrowsUSOE() {
   @Test
   public void hashCodeThrowsUSOE() {
     try {
-      assertThat(5).hashCode();
+      int unused = assertThat(5).hashCode();
     } catch (UnsupportedOperationException expected) {
       assertThat(expected).hasMessage("Subject.hashCode() is not supported.");
       return;