From 63f39c5009c2cf5e2c84650411733ad50e4397d3 Mon Sep 17 00:00:00 2001
From: Andy Hanson <anhans@microsoft.com>
Date: Fri, 9 Sep 2016 08:42:05 -0700
Subject: [PATCH] Handle `OmittedExpression` nodes in binding patterns

---
 scripts/tslint/preferConstRule.ts | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/scripts/tslint/preferConstRule.ts b/scripts/tslint/preferConstRule.ts
index 60d771863be7d..9425d2b60795a 100644
--- a/scripts/tslint/preferConstRule.ts
+++ b/scripts/tslint/preferConstRule.ts
@@ -93,11 +93,16 @@ class PreferConstWalker extends Lint.RuleWalker {
 
     private visitBindingPatternIdentifiers(pattern: ts.BindingPattern) {
         for (const element of pattern.elements) {
-            if (element.name.kind === ts.SyntaxKind.Identifier) {
-                this.markAssignment(element.name as ts.Identifier);
+            if (element.kind !== ts.SyntaxKind.BindingElement) {
+                continue;
+            }
+
+            const name = (<ts.BindingElement>element).name;
+            if (name.kind === ts.SyntaxKind.Identifier) {
+                this.markAssignment(name as ts.Identifier);
             }
             else {
-                this.visitBindingPatternIdentifiers(element.name as ts.BindingPattern);
+                this.visitBindingPatternIdentifiers(name as ts.BindingPattern);
             }
         }
     }
@@ -191,7 +196,9 @@ class PreferConstWalker extends Lint.RuleWalker {
 
     private collectBindingPatternIdentifiers(value: ts.VariableDeclaration, pattern: ts.BindingPattern, table: ts.MapLike<DeclarationUsages>) {
         for (const element of pattern.elements) {
-            this.collectNameIdentifiers(value, element.name, table);
+            if (element.kind === ts.SyntaxKind.BindingElement) {
+                this.collectNameIdentifiers(value, (<ts.BindingElement>element).name, table);
+            }
         }
     }
 }