From: Alex Lam S.L <alexlamsl@gmail.com>
Date: Mon, 11 May 2020 18:29:33 +0000 (+0100)
Subject: fix corner case in `reduce_vars` (#3881)
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=e8a7956b6f0a71bed038a2b8936eb30d91e94d73;p=UglifyJS.git

fix corner case in `reduce_vars` (#3881)

fixes #3880
---

diff --git a/lib/compress.js b/lib/compress.js
index 08abde9b..1e33dc10 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -797,8 +797,12 @@ merge(Compressor.prototype, {
                     d.recursive_refs++;
                 } else if (value && ref_once(tw, compressor, d)) {
                     d.in_loop = tw.loop_ids[d.id] !== tw.in_loop;
-                    d.single_use = value instanceof AST_Lambda && !value.pinned()
-                        || !d.in_loop && d.scope === this.scope && value.is_constant_expression();
+                    d.single_use = value instanceof AST_Lambda
+                            && !value.pinned()
+                            && (!d.in_loop || tw.parent() instanceof AST_Call)
+                        || !d.in_loop
+                            && d.scope === this.scope
+                            && value.is_constant_expression();
                 } else {
                     d.single_use = false;
                 }
diff --git a/test/compress/reduce_vars.js b/test/compress/reduce_vars.js
index 00cebcd6..262a77f2 100644
--- a/test/compress/reduce_vars.js
+++ b/test/compress/reduce_vars.js
@@ -7047,3 +7047,24 @@ issue_3866: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3880: {
+    options = {
+        reduce_funcs: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            while (a.var ^= 1);
+            console.log("PASS");
+        })(function() {});
+    }
+    expect: {
+        (function(a) {
+            while (a.var ^= 1);
+            console.log("PASS");
+        })(function() {});
+    }
+    expect_stdout: "PASS"
+}