From 6eba035ea97232d3a629f513ef8cd449fa41ffbc Mon Sep 17 00:00:00 2001
From: lharker <lharker@google.com>
Date: Thu, 9 Aug 2018 16:30:35 -0700
Subject: [PATCH] Attach JSDoc to correct nodes in array pattern with elision

e.g. const [, /** string */ str] = [];

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=208130879
---
 .../javascript/jscomp/parsing/parser/Parser.java |  3 ++-
 .../javascript/jscomp/parsing/ParserTest.java    | 16 ++++++++++++++++
 2 files changed, 18 insertions(+), 1 deletion(-)

diff --git a/src/com/google/javascript/jscomp/parsing/parser/Parser.java b/src/com/google/javascript/jscomp/parsing/parser/Parser.java
index 461286fa519..2c73a27e64c 100644
--- a/src/com/google/javascript/jscomp/parsing/parser/Parser.java
+++ b/src/com/google/javascript/jscomp/parsing/parser/Parser.java
@@ -3683,8 +3683,9 @@ private ParseTree parseArrayPattern(PatternKind kind) {
     eat(TokenType.OPEN_SQUARE);
     while (peek(TokenType.COMMA) || peekArrayPatternElement()) {
       if (peek(TokenType.COMMA)) {
+        SourcePosition nullStart = getTreeStartLocation();
         eat(TokenType.COMMA);
-        elements.add(new NullTree(getTreeLocation(getTreeStartLocation())));
+        elements.add(new NullTree(getTreeLocation(nullStart)));
       } else {
         elements.add(parsePatternAssignmentTarget(kind));
 
diff --git a/test/com/google/javascript/jscomp/parsing/ParserTest.java b/test/com/google/javascript/jscomp/parsing/ParserTest.java
index 13ac4551bbc..6424ad9ff6d 100644
--- a/test/com/google/javascript/jscomp/parsing/ParserTest.java
+++ b/test/com/google/javascript/jscomp/parsing/ParserTest.java
@@ -1123,6 +1123,22 @@ public void testInlineJSDocAttachmentToArrayPatElementQualifiedNameWithDefault()
     assertNodeHasJSDocInfoWithJSType(xYZName, STRING_TYPE);
   }
 
+  public void testInlineJSDocAttachmentToArrayPatElementAfterElision() {
+    Node letNode =
+        parse("let [, /** string */ x] = [];")
+            .getFirstChild();
+    assertNode(letNode).hasType(Token.LET);
+
+    Node destructuringLhs = letNode.getFirstChild();
+    Node arrayPattern = destructuringLhs.getFirstChild();
+    Node empty = arrayPattern.getFirstChild();
+    assertNode(empty).hasToken(Token.EMPTY);
+    assertNode(empty).hasCharno(5);
+    assertNode(empty).hasLength(1);
+    Node xVarName = arrayPattern.getSecondChild();
+    assertNodeHasJSDocInfoWithJSType(xVarName, STRING_TYPE);
+  }
+
   public void testInlineJSDocAttachmentToObjLitNormalProp() {
     Node letNode = parse("let x = { normalProp: /** string */ normalPropTarget };").getFirstChild();
     assertNode(letNode).hasType(Token.LET);