From ec7cabed3bf0237296c2e297eae1a039852c4af8 Mon Sep 17 00:00:00 2001
From: alexlamsl <alexlamsl@gmail.com>
Date: Wed, 31 Jan 2018 18:10:35 +0800
Subject: [PATCH] relax `collapse_vars` on `AST_Exit`

---
 lib/compress.js                |  1 -
 test/compress/collapse_vars.js | 55 ++++++++++++++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/lib/compress.js b/lib/compress.js
index d0ef5f5d..db6ee8be 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -1044,7 +1044,6 @@ merge(Compressor.prototype, {
                 // but are otherwise not safe to scan into or beyond them.
                 var sym;
                 if (node instanceof AST_Call
-                    || node instanceof AST_Exit
                     || node instanceof AST_PropAccess
                         && (side_effects || node.expression.may_throw_on_access(compressor))
                     || node instanceof AST_SymbolRef
diff --git a/test/compress/collapse_vars.js b/test/compress/collapse_vars.js
index 4172b33b..046daf9f 100644
--- a/test/compress/collapse_vars.js
+++ b/test/compress/collapse_vars.js
@@ -4107,3 +4107,58 @@ unsafe_builtin: {
     }
     expect_stdout: "1 4"
 }
+
+return_1: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        var log = console.log;
+        function f(b, c) {
+            var a = c;
+            if (b) return b;
+            log(a);
+        }
+        f(false, 1);
+        f(true, 2);
+    }
+    expect: {
+        var log = console.log;
+        function f(b, c) {
+            if (b) return b;
+            log(c);
+        }
+        f(false, 1);
+        f(true, 2);
+    }
+    expect_stdout: "1"
+}
+
+return_2: {
+    options = {
+        collapse_vars: true,
+        unused: true,
+    }
+    input: {
+        var log = console.log;
+        function f(b, c) {
+            var a = b <<= c;
+            if (b) return b;
+            log(a);
+        }
+        f(false, 1);
+        f(true, 2);
+    }
+    expect: {
+        var log = console.log;
+        function f(b, c) {
+            var a = b <<= c;
+            if (b) return b;
+            log(a);
+        }
+        f(false, 1);
+        f(true, 2);
+    }
+    expect_stdout: "0"
+}