From b6868a030afb7a86efcbc3b77b0cbda68c762a68 Mon Sep 17 00:00:00 2001
From: kzc <zaxxon2011@gmail.com>
Date: Wed, 22 Nov 2017 18:35:09 -0500
Subject: [PATCH] fix `properties` for array literal with spread

---
 lib/compress.js          | 11 +++--
 test/compress/harmony.js | 86 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 94 insertions(+), 3 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index aa97b13c..9a2ceeb9 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -4996,21 +4996,26 @@ merge(Compressor.prototype, {
             && prop instanceof AST_Number && expr instanceof AST_Array) {
             var index = prop.getValue();
             var elements = expr.elements;
-            if (index in elements) {
+            FLATTEN: if (index in elements) {
                 var flatten = true;
                 var values = [];
                 for (var i = elements.length; --i > index;) {
-                    var value = elements[i].drop_side_effect_free(compressor);
+                    var value = elements[i];
+                    if (value instanceof AST_Expansion) break FLATTEN;
+                    var value = value.drop_side_effect_free(compressor);
                     if (value) {
                         values.unshift(value);
                         if (flatten && value.has_side_effects(compressor)) flatten = false;
                     }
                 }
                 var retValue = elements[index];
+                if (retValue instanceof AST_Expansion) break FLATTEN;
                 retValue = retValue instanceof AST_Hole ? make_node(AST_Undefined, retValue) : retValue;
                 if (!flatten) values.unshift(retValue);
                 while (--i >= 0) {
-                    var value = elements[i].drop_side_effect_free(compressor);
+                    var value = elements[i];
+                    if (value instanceof AST_Expansion) break FLATTEN;
+                    value = value.drop_side_effect_free(compressor);
                     if (value) values.unshift(value);
                     else index--;
                 }
diff --git a/test/compress/harmony.js b/test/compress/harmony.js
index 11b36b2d..1c7b7fbf 100644
--- a/test/compress/harmony.js
+++ b/test/compress/harmony.js
@@ -975,3 +975,89 @@ shorthand_keywords: {
     expect_stdout: true
     node_version: ">=4"
 }
+
+array_literal_with_spread: {
+    options = {
+        properties: true,
+        side_effects: true,
+    }
+    input: {
+        var f = (x) => [...x][0];
+        console.log(f(["PASS"]));
+
+        console.log([10, ...[], 20, ...[30, 40], 50]["length"]);
+        console.log([10, ...[], 20, ...[30, 40], 50][0]);
+        console.log([10, ...[], 20, ...[30, 40], 50][1]);
+        console.log([10, ...[], 20, ...[30, 40], 50][2]);
+        console.log([10, ...[], 20, ...[30, 40], 50][3]);
+        console.log([10, ...[], 20, ...[30, 40], 50][4]);
+        console.log([10, ...[], 20, ...[30, 40], 50][5]);
+
+        console.log([10, 20][0]);
+        console.log([10, 20][1]);
+        console.log([10, 20][2]);
+
+        console.log([...[], 10, 20][0]);
+        console.log([...[], 10, 20][1]);
+        console.log([...[], 10, 20][2]);
+
+        console.log([10, ...[], 20][0]);
+        console.log([10, ...[], 20][1]);
+        console.log([10, ...[], 20][2]);
+
+        console.log([10, 20, ...[]][0]);
+        console.log([10, 20, ...[]][1]);
+        console.log([10, 20, ...[]][2]);
+    }
+    expect: {
+        var f = x => [ ...x ][0];
+        console.log(f([ "PASS" ]));
+
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ]["length"]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][0]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][1]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][2]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][3]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][4]);
+        console.log([ 10, ...[], 20, ...[ 30, 40 ], 50 ][5]);
+
+        console.log(10);
+        console.log(20);
+        console.log([ 10, 20 ][2]);
+
+        console.log([...[], 10, 20][0]);
+        console.log([...[], 10, 20][1]);
+        console.log([...[], 10, 20][2]);
+
+        console.log([10, ...[], 20][0]);
+        console.log([10, ...[], 20][1]);
+        console.log([10, ...[], 20][2]);
+
+        console.log([10, 20, ...[]][0]);
+        console.log([10, 20, ...[]][1]);
+        console.log([10, 20, ...[]][2]);
+    }
+    expect_stdout: [
+        "PASS",
+        "5",
+        "10",
+        "20",
+        "30",
+        "40",
+        "50",
+        "undefined",
+        "10",
+        "20",
+        "undefined",
+        "10",
+        "20",
+        "undefined",
+        "10",
+        "20",
+        "undefined",
+        "10",
+        "20",
+        "undefined",
+    ]
+    node_version: ">=6"
+}