Consolidate static #equals matchers.

And fix a javadoc.

RELNOTES: N/A

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=207264130

core/src/main/java/com/google/errorprone/bugpatterns/AbstractReferenceEquality.java

@@ -18,9 +18,8 @@
 
 import static com.google.errorprone.dataflow.nullnesspropagation.Nullness.NONNULL;
 import static com.google.errorprone.dataflow.nullnesspropagation.Nullness.NULL;
-import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static com.google.errorprone.matchers.Matchers.staticEqualsInvocation;
 
 import com.google.errorprone.VisitorState;
 import com.google.errorprone.bugpatterns.BugChecker.BinaryTreeMatcher;
@@ -50,10 +49,8 @@
  */
 public abstract class AbstractReferenceEquality extends BugChecker implements BinaryTreeMatcher {
 
-  private static final Matcher<ExpressionTree> EQUALS_STATIC_METHODS =
-      anyOf(
-          staticMethod().onClass("com.google.common.base.Objects").named("equal"),
-          staticMethod().onClass("java.util.Objects").named("equals"));
+  private static final Matcher<MethodInvocationTree> EQUALS_STATIC_METHODS =
+      staticEqualsInvocation();
 
   private static final Matcher<ExpressionTree> OBJECT_INSTANCE_EQUALS =
       instanceMethod()
@@ -168,7 +165,7 @@ private static Optional<Fix> inOrStatementWithEqualsCheck(VisitorState state, Bi
     MethodInvocationTree other = (MethodInvocationTree) otherExpression;
 
     // a == b || Objects.equals(a, b) => Objects.equals(a, b)
-    if (EQUALS_STATIC_METHODS.matches(otherExpression, state)) {
+    if (EQUALS_STATIC_METHODS.matches(other, state)) {
       List<? extends ExpressionTree> arguments = other.getArguments();
       if (treesMatch(arguments.get(0), arguments.get(1), lhs, rhs)) {
         return Optional.of(SuggestedFix.replace(parent, state.getSourceForNode(otherExpression)));

core/src/main/java/com/google/errorprone/bugpatterns/ArrayAsKeyOfSetOrMap.java

@@ -34,7 +34,12 @@
 import com.sun.tools.javac.code.Type;
 import java.util.List;
 
-/** Bug checker to detect usage of {@code Set<T[]>} or {@code Map<T[], E>}. */
+/**
+ * Warns that users should not have an array as a key to a Set or Map
+ *
+ * @author siyuanl@google.com (Siyuan Liu)
+ * @author eleanorh@google.com (Eleanor Harris)
+ */
 @BugPattern(
     name = "ArrayAsKeyOfSetOrMap",
     summary =
@@ -43,13 +48,6 @@
             + "consider using a List instead. Otherwise, use IdentityHashMap/Set, "
             + "a Map from a library that handles object arrays, or an Iterable/List of pairs.",
     severity = WARNING)
-
-/**
- * Warns that users should not have an array as a key to a Set or Map
- *
- * @author siyuanl@google.com (Siyuan Liu)
- * @author eleanorh@google.com (Eleanor Harris)
- */
 public class ArrayAsKeyOfSetOrMap extends BugChecker
     implements MethodInvocationTreeMatcher, NewClassTreeMatcher {
 

core/src/main/java/com/google/errorprone/bugpatterns/ArrayEquals.java

@@ -20,10 +20,10 @@
 import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
 import static com.google.errorprone.matchers.Description.NO_MATCH;
 import static com.google.errorprone.matchers.Matchers.allOf;
-import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.argument;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
-import static com.google.errorprone.matchers.Matchers.staticMethod;
+import static com.google.errorprone.matchers.Matchers.isArrayType;
+import static com.google.errorprone.matchers.Matchers.staticEqualsInvocation;
 import static com.google.errorprone.predicates.TypePredicates.isArray;
 
 import com.google.errorprone.BugPattern;
@@ -34,8 +34,6 @@
 import com.google.errorprone.fixes.SuggestedFix;
 import com.google.errorprone.matchers.Description;
 import com.google.errorprone.matchers.Matcher;
-import com.google.errorprone.matchers.Matchers;
-import com.sun.source.tree.ExpressionTree;
 import com.sun.source.tree.MethodInvocationTree;
 import com.sun.tools.javac.tree.JCTree.JCFieldAccess;
 
@@ -49,26 +47,11 @@
 public class ArrayEquals extends BugChecker implements MethodInvocationTreeMatcher {
   /** Matches when the equals instance method is used to compare two arrays. */
   private static final Matcher<MethodInvocationTree> instanceEqualsMatcher =
-      Matchers.allOf(
-          instanceMethod().onClass(isArray()).named("equals"),
-          argument(0, Matchers.<ExpressionTree>isArrayType()));
+      allOf(instanceMethod().onClass(isArray()).named("equals"), argument(0, isArrayType()));
 
-  /**
-   * Matches when the following methods compare two arrays:
-   *
-   * <ul>
-   *   <li>Android android.support.v4.util.ObjectsCompat#equals
-   *   <li>Guava com.google.common.base.Objects#equal
-   *   <li>JDK7 java.util.Objects#equals
-   */
+  /** Matches when {@link java.util.Objects#equals}-like methods compare two arrays. */
   private static final Matcher<MethodInvocationTree> staticEqualsMatcher =
-      allOf(
-          anyOf(
-              staticMethod().onClass("android.support.v4.util.ObjectsCompat").named("equals"),
-              staticMethod().onClass("com.google.common.base.Objects").named("equal"),
-              staticMethod().onClass("java.util.Objects").named("equals")),
-          argument(0, Matchers.<ExpressionTree>isArrayType()),
-          argument(1, Matchers.<ExpressionTree>isArrayType()));
+      allOf(staticEqualsInvocation(), argument(0, isArrayType()), argument(1, isArrayType()));
 
   /**
    * Suggests replacing with Arrays.equals(a, b). Also adds the necessary import statement for

core/src/main/java/com/google/errorprone/bugpatterns/EqualsWrongThing.java

@@ -28,6 +28,7 @@
 import static com.google.errorprone.matchers.Matchers.methodIsNamed;
 import static com.google.errorprone.matchers.Matchers.methodReturns;
 import static com.google.errorprone.matchers.Matchers.not;
+import static com.google.errorprone.matchers.Matchers.staticEqualsInvocation;
 import static com.google.errorprone.matchers.Matchers.staticMethod;
 import static com.google.errorprone.matchers.Matchers.variableType;
 import static com.google.errorprone.matchers.method.MethodMatchers.instanceMethod;
@@ -79,11 +80,8 @@ public final class EqualsWrongThing extends BugChecker implements MethodTreeMatc
           methodHasParameters(variableType(isSameType(OBJECT_TYPE))),
           not(isStatic()));
 
-  private static final Matcher<ExpressionTree> COMPARISON_METHOD =
-      anyOf(
-          staticMethod().onClass("java.util.Arrays").named("equals"),
-          staticMethod().onClass("com.google.common.base.Objects").named("equal"),
-          staticMethod().onClass("java.util.Objects").named("equals"));
+  private static final Matcher<MethodInvocationTree> COMPARISON_METHOD =
+      anyOf(staticMethod().onClass("java.util.Arrays").named("equals"), staticEqualsInvocation());
 
   private static final Matcher<ExpressionTree> EQUALS =
       instanceMethod().anyClass().named("equals").withParameters("java.lang.Object");

core/src/main/java/com/google/errorprone/bugpatterns/SelfEquals.java

@@ -20,10 +20,10 @@
 import static com.google.errorprone.BugPattern.SeverityLevel.ERROR;
 import static com.google.errorprone.matchers.Description.NO_MATCH;
 import static com.google.errorprone.matchers.Matchers.allOf;
-import static com.google.errorprone.matchers.Matchers.anyOf;
 import static com.google.errorprone.matchers.Matchers.instanceMethod;
 import static com.google.errorprone.matchers.Matchers.receiverSameAsArgument;
 import static com.google.errorprone.matchers.Matchers.sameArgument;
+import static com.google.errorprone.matchers.Matchers.staticEqualsInvocation;
 import static com.google.errorprone.matchers.Matchers.toType;
 import static com.google.errorprone.matchers.method.MethodMatchers.staticMethod;
 
@@ -74,11 +74,7 @@ public class SelfEquals extends BugChecker implements MethodInvocationTreeMatche
           receiverSameAsArgument(0));
 
   private static final Matcher<MethodInvocationTree> STATIC_MATCHER =
-      allOf(
-          anyOf(
-              staticMethod().onClass("com.google.common.base.Objects").named("equal"),
-              staticMethod().onClass("java.util.Objects").named("equals")),
-          sameArgument(0, 1));
+      allOf(staticEqualsInvocation(), sameArgument(0, 1));
 
   @Override
   public Description matchMethodInvocation(MethodInvocationTree tree, VisitorState state) {