fix `reduce_vars` on `this` (#2145)

fixes #2140

1 files changed, 25 insertions, 0 deletions

diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index cef29832..5906a971 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -2575,3 +2575,28 @@ accessor: {
     }
     expect_stdout: "1 1"
 }
+
+for_in_prop: {
+    options = {
+        reduce_vars: true,
+    }
+    input: {
+        var a = {
+            foo: function() {
+                for (this.b in [1, 2]);
+            }
+        };
+        a.foo();
+        console.log(a.b);
+    }
+    expect: {
+        var a = {
+            foo: function() {
+                for (this.b in [1, 2]);
+            }
+        };
+        a.foo();
+        console.log(a.b);
+    }
+    expect_stdout: "1"
+}