Small fix in NodeUtil.getRValueOfLValue:

In ES5 a var statement looks like

VAR
  NAME
    rhs

so the RHS is the first (and only) child of the LHS. But in ES6 it can also be

VAR
  DESTRUCTURING_LHS
    OBJECT_PATTERN or ARRAY_PATTERN
    rhs

in which case the RHS is the last child of the LHS

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=177348132

src/com/google/javascript/jscomp/NodeUtil.java

@@ -5108,6 +5108,9 @@ static Node getRValueOfLValue(Node n) {
       case VAR:
       case LET:
       case CONST:
+        return n.getLastChild();
+      case DESTRUCTURING_LHS:
+        return parent.getLastChild();
       case OBJECTLIT:
         return n.getFirstChild();
       case FUNCTION:

test/com/google/javascript/jscomp/NodeUtilTest.java

@@ -43,6 +43,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Set;
+import javax.annotation.Nullable;
 import junit.framework.TestCase;
 
 /**
@@ -2288,10 +2289,10 @@ public void testGetRValueOfLValue() {
   }
 
   /**
-   * When the left side is a destructuring pattern, generally it's not possible to identify the
-   * RHS for a specific name on the LHS.
+   * When the left side is a destructuring pattern, generally it's not possible to identify the RHS
+   * for a specific name on the LHS.
    */
-  public void testGetRValueOfLValueDestructuring() {
+  public void testGetRValueOfLValueInDestructuringPattern() {
     assertThat(NodeUtil.getRValueOfLValue(getNameNode(parse("var [x] = rhs;"), "x"))).isNull();
     assertThat(NodeUtil.getRValueOfLValue(getNameNode(parse("var [x, y] = rhs;"), "x"))).isNull();
     assertThat(NodeUtil.getRValueOfLValue(getNameNode(parse("var [y, x] = rhs;"), "x"))).isNull();
@@ -2307,6 +2308,36 @@ public void testGetRValueOfLValueDestructuring() {
     assertThat(NodeUtil.getRValueOfLValue(x)).isNull();
   }
 
+  public void testGetRValueOfLValueDestructuringPattern() {
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var [x] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var [x, y] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var [y, x] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var {x: x} = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var {y: x} = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getPattern(parse("var {x} = 'rhs';"))))
+        .hasType(Token.STRING);
+  }
+
+  public void testGetRValueOfLValueDestructuringLhs() {
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var [x] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var [x, y] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var [y, x] = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var {x: x} = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var {y: x} = 'rhs';"))))
+        .hasType(Token.STRING);
+    assertNode(NodeUtil.getRValueOfLValue(getDestructuringLhs(parse("var {x} = 'rhs';"))))
+        .hasType(Token.STRING);
+  }
+
   public void testIsNaN() {
     assertTrue(NodeUtil.isNaN(getNode("NaN")));
     assertFalse(NodeUtil.isNaN(getNode("Infinity")));
@@ -3207,6 +3238,36 @@ private static Node getNameNode(Node n, String name) {
     return null;
   }
 
+  /** @return The first node in {@code tree} that is an array pattern or object pattern. */
+  @Nullable
+  private static Node getPattern(Node tree) {
+    if (tree.isDestructuringPattern()) {
+      return tree;
+    }
+    for (Node c : tree.children()) {
+      Node result = getPattern(c);
+      if (result != null) {
+        return result;
+      }
+    }
+    return null;
+  }
+
+  /** @return The first node in {@code tree} that is a DESTRUCTURING_LHS. */
+  @Nullable
+  private static Node getDestructuringLhs(Node tree) {
+    if (tree.isDestructuringLhs()) {
+      return tree;
+    }
+    for (Node c : tree.children()) {
+      Node result = getDestructuringLhs(c);
+      if (result != null) {
+        return result;
+      }
+    }
+    return null;
+  }
+
   private static boolean isValidPropertyName(String s) {
     return NodeUtil.isValidPropertyName(FeatureSet.ES3, s);
   }