From e773f0392769794173358b362a645facb51b2ad2 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Sat, 3 Feb 2018 01:33:09 +0800
Subject: [PATCH] fix assignment logic in `reduce_vars` (#2872)

fixes #2869
---
 lib/compress.js              | 12 ++++++------
 test/compress/reduce_vars.js | 26 ++++++++++++++++++++++++++
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 832f64f2..77636cb2 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -710,19 +710,19 @@ merge(Compressor.prototype, {
         def(AST_VarDef, function(tw, descend) {
             var node = this;
             var d = node.name.definition();
-            if (safe_to_assign(tw, d, node.value)) {
-                if (node.value) {
+            if (node.value) {
+                if (safe_to_assign(tw, d, node.value)) {
                     d.fixed = function() {
                         return node.value;
                     };
                     tw.loop_ids[d.id] = tw.in_loop;
                     mark(tw, d, false);
                     descend();
+                    mark(tw, d, true);
+                    return true;
+                } else {
+                    d.fixed = false;
                 }
-                mark(tw, d, true);
-                return true;
-            } else if (node.value) {
-                d.fixed = false;
             }
         });
         def(AST_While, function(tw) {
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 761af9e2..c0148204 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -5507,3 +5507,29 @@ issue_2860_2: {
     }
     expect_stdout: "1"
 }
+
+issue_2869: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+    }
+    input: {
+        var c = "FAIL";
+        (function f(a) {
+            var a;
+            if (!f) a = 0;
+            if (a) c = "PASS";
+        })(1);
+        console.log(c);
+    }
+    expect: {
+        var c = "FAIL";
+        (function f(a) {
+            var a;
+            if (!f) a = 0;
+            if (a) c = "PASS";
+        })(1);
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}
-- 
2.34.1