fix corner cases in `reduce_vars` & `unused` (#4306)

2 files changed, 100 insertions, 0 deletions

diff --git a/test/compress/const.js b/test/compress/const.js
index 7e393d4f..8dbe74da 100644
--- a/test/compress/const.js
+++ b/test/compress/const.js
@@ -1257,3 +1257,51 @@ issue_4290_1: {
     }
     expect_stdout: true
 }
+
+issue_4305_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            const arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect: {
+        (function() {
+            const arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect_stdout: true
+}
+
+issue_4305_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            const a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect: {
+        (function(a) {
+            const a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect_stdout: true
+}
diff --git a/test/compress/let.js b/test/compress/let.js
index 0669b36f..76641c3f 100644
--- a/test/compress/let.js
+++ b/test/compress/let.js
@@ -1134,3 +1134,55 @@ issue_4290_2: {
     expect_stdout: "PASS"
     node_version: ">=4"
 }
+
+issue_4305_1: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        (function() {
+            let arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect: {
+        (function() {
+            let arguments = function() {
+                while (console.log("PASS"));
+            };
+            arguments();
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=6"
+}
+
+issue_4305_2: {
+    options = {
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        "use strict";
+        (function(a) {
+            let a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect: {
+        "use strict";
+        (function(a) {
+            let a = function() {
+                while (console.log("aaaaa"));
+            };
+            a();
+        })();
+    }
+    expect_stdout: true
+    node_version: ">=4"
+}