fix corner case in `unused` (#4236)

fixes #4235

2 files changed, 45 insertions, 0 deletions

diff --git a/test/compress/drop-unused.js b/test/compress/drop-unused.js
index 257d7a76..4448bdd8 100644
--- a/test/compress/drop-unused.js
+++ b/test/compress/drop-unused.js
@@ -3085,3 +3085,30 @@ issue_4184: {
     }
     expect_stdout: "42"
 }
+
+issue_4235: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        (function() {
+            {
+                const f = 0;
+            }
+            (function f() {
+                var f = console.log(f);
+            })();
+        })();
+    }
+    expect: {
+        (function() {
+            f = console.log(f),
+            void 0;
+            var f;
+        })();
+    }
+    expect_stdout: "undefined"
+}
diff --git a/test/compress/ie8.js b/test/compress/ie8.js
index f2132579..2a7dace3 100644
--- a/test/compress/ie8.js
+++ b/test/compress/ie8.js
@@ -2859,3 +2859,21 @@ issue_4186: {
     }
     expect_stdout: "NaN"
 }
+
+issue_4235: {
+    options = {
+        ie8: true,
+        unused: true,
+    }
+    input: {
+        try {} catch (e) {}
+        console.log(function e() {
+            var e = 0;
+        }());
+    }
+    expect: {
+        try {} catch (e) {}
+        console.log(function e() {}());
+    }
+    expect_stdout: "undefined"
+}