From be8ccc3ab5c34c4d4861e58bb1634d6dbc4a53f0 Mon Sep 17 00:00:00 2001
From: "Alex Lam S.L" <alexlamsl@gmail.com>
Date: Tue, 4 Oct 2022 09:03:24 +0100
Subject: [PATCH] fix corner case in `varify` (#5698)

fixes #5697
---
 lib/compress.js         |   7 +-
 test/compress/varify.js | 162 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 165 insertions(+), 4 deletions(-)

diff --git a/lib/compress.js b/lib/compress.js
index 7e5f7e07e01..71d3654319a 100644
--- a/lib/compress.js
+++ b/lib/compress.js
@@ -9347,7 +9347,7 @@ Compressor.prototype.compress = function(node) {
                         return !same_scope(def) || may_overlap(compressor, def);
                     }
                 }, true)) {
-                self.init = to_var(self.init);
+                self.init = to_var(self.init, self.resolve());
             }
         }
         return self;
@@ -10161,14 +10161,13 @@ Compressor.prototype.compress = function(node) {
         }
     }
 
-    function to_var(stat) {
+    function to_var(stat, scope) {
         return make_node(AST_Var, stat, {
             definitions: stat.definitions.map(function(defn) {
                 return make_node(AST_VarDef, defn, {
                     name: defn.name.convert_symbol(AST_SymbolVar, function(name, node) {
                         var def = name.definition();
                         def.orig[def.orig.indexOf(node)] = name;
-                        var scope = def.scope.resolve();
                         if (def.scope === scope) return;
                         def.scope = scope;
                         scope.variables.set(def.name, def);
@@ -10194,7 +10193,7 @@ Compressor.prototype.compress = function(node) {
             return !defn.name.match_symbol(function(node) {
                 if (node instanceof AST_SymbolDeclaration) return !can_varify(compressor, node);
             }, true);
-        }) ? to_var(self) : self;
+        }) ? to_var(self, compressor.find_parent(AST_Scope)) : self;
     }
 
     OPT(AST_Const, varify);
diff --git a/test/compress/varify.js b/test/compress/varify.js
index 19e2ce8a949..a7d983a69ef 100644
--- a/test/compress/varify.js
+++ b/test/compress/varify.js
@@ -682,3 +682,165 @@ issue_5516: {
     expect_stdout: "function"
     node_version: ">=4"
 }
+
+issue_5697_1: {
+    options = {
+        if_return: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(function() {
+            f();
+            return typeof a;
+            function f() {
+                (function() {
+                    for (var k in { foo: 42 }) {
+                        const a = k;
+                        console.log(a);
+                    }
+                })();
+            }
+        }());
+    }
+    expect: {
+        console.log(function() {
+            (function() {
+                for (var k in { foo: 42 }) {
+                    var a = k;
+                    console.log(a);
+                }
+            })();
+            return typeof a;
+        }());
+    }
+    expect_stdout: [
+        "foo",
+        "undefined",
+    ]
+}
+
+issue_5697_2: {
+    options = {
+        if_return: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        console.log(function() {
+            f();
+            return typeof a;
+            function f() {
+                (function() {
+                    for (var k in { foo: 42 }) {
+                        let a = k;
+                        console.log(a);
+                    }
+                })();
+            }
+        }());
+    }
+    expect: {
+        "use strict";
+        console.log(function() {
+            (function() {
+                for (var k in { foo: 42 }) {
+                    var a = k;
+                    console.log(a);
+                }
+            })();
+            return typeof a;
+        }());
+    }
+    expect_stdout: [
+        "foo",
+        "undefined",
+    ]
+    node_version: ">=4"
+}
+
+issue_5697_3: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        console.log(function() {
+            f();
+            return typeof a;
+            function f() {
+                (function() {
+                    for (var k in { foo: 42 }) {
+                        const a = k;
+                        console.log(a);
+                    }
+                })();
+            }
+        }());
+    }
+    expect: {
+        console.log(function() {
+            (function() {
+                for (var k in { foo: 42 }) {
+                    var a = k;
+                    console.log(a);
+                }
+            })();
+            return typeof a;
+        }());
+    }
+    expect_stdout: [
+        "foo",
+        "undefined",
+    ]
+}
+
+issue_5697_4: {
+    options = {
+        inline: true,
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+        varify: true,
+    }
+    input: {
+        "use strict";
+        console.log(function() {
+            f();
+            return typeof a;
+            function f() {
+                (function() {
+                    for (var k in { foo: 42 }) {
+                        let a = k;
+                        console.log(a);
+                    }
+                })();
+            }
+        }());
+    }
+    expect: {
+        "use strict";
+        console.log(function() {
+            (function() {
+                for (var k in { foo: 42 }) {
+                    var a = k;
+                    console.log(a);
+                }
+            })();
+            return typeof a;
+        }());
+    }
+    expect_stdout: [
+        "foo",
+        "undefined",
+    ]
+    node_version: ">=4"
+}