From 2944e3df7d743e32737ddf51d3c91cd1ccb448b2 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 9 May 2017 17:44:28 +0800
Subject: [PATCH] fix `collapse_vars` on destructuring declarations (#1889)

fixes #1886
---
 lib/compress.js                |  2 +-
 test/compress/destructuring.js | 15 +++++++++++++++
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index 21ff25cc..8abf5d11 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -799,7 +799,7 @@ merge(Compressor.prototype, {
             }
 
             function get_lhs(expr) {
-                if (expr instanceof AST_VarDef) {
+                if (expr instanceof AST_VarDef && expr.name instanceof AST_SymbolDeclaration) {
                     var def = expr.name.definition();
                     if (def.orig.length > 1
                         || def.references.length == 1 && (!def.global || compressor.toplevel(def))) {
diff --git a/test/compress/destructuring.js b/test/compress/destructuring.js
index 8603a38b..70f5d053 100644
--- a/test/compress/destructuring.js
+++ b/test/compress/destructuring.js
@@ -315,3 +315,18 @@ unused: {
         console.log(a);
     }
 }
+
+issue_1886: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        let [a] = [1];
+        console.log(a);
+    }
+    expect: {
+        let [a] = [1];
+        console.log(a);
+    }
+    expect_exact: "1"
+}