fix corner case in `ie8` & `mangle` (#3479)

fixes #3478

2 files changed, 259 insertions, 13 deletions

diff --git a/lib/scope.js b/lib/scope.js
index bd6cb26a..7da982a0 100644
--- a/lib/scope.js
+++ b/lib/scope.js
@@ -419,7 +419,9 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
             if (options.cache && node instanceof AST_Toplevel) {
                 node.globals.each(mangle);
             }
-            node.variables.each(mangle);
+            node.variables.each(function(def) {
+                if (!defer_redef(def)) mangle(def);
+            });
             return true;
         }
         if (node instanceof AST_Label) {
@@ -432,22 +434,11 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
         }
         if (!options.ie8 && node instanceof AST_Catch) {
             var def = node.argname.definition();
-            var redef = def.redefined();
-            if (redef) {
-                redefined.push(def);
-                reference(node.argname);
-                def.references.forEach(reference);
-            }
+            var redef = defer_redef(def, node.argname);
             descend();
             if (!redef) mangle(def);
             return true;
         }
-
-        function reference(sym) {
-            sym.thedef = redef;
-            sym.reference(options);
-            sym.thedef = def;
-        }
     });
     this.walk(tw);
     redefined.forEach(mangle);
@@ -456,6 +447,21 @@ AST_Toplevel.DEFMETHOD("mangle_names", function(options) {
         if (options.reserved.has[def.name]) return;
         def.mangle(options);
     }
+
+    function defer_redef(def, node) {
+        var redef = def.redefined();
+        if (!redef) return false;
+        redefined.push(def);
+        def.references.forEach(reference);
+        if (node) reference(node);
+        return true;
+
+        function reference(sym) {
+            sym.thedef = redef;
+            sym.reference(options);
+            sym.thedef = def;
+        }
+    }
 });
 
 AST_Toplevel.DEFMETHOD("find_colliding_names", function(options) {
diff --git a/test/compress/ie8.js b/test/compress/ie8.js
index 586955d9..f371bbf0 100644
--- a/test/compress/ie8.js
+++ b/test/compress/ie8.js
@@ -1321,3 +1321,243 @@ issue_3475_ie8_toplevel: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3478_1: {
+    rename = true
+    mangle = {
+        ie8: false,
+        toplevel: false,
+    }
+    input: {
+        "aaaaaaaaaa";
+        (function f() {
+            (function f() {
+                var a;
+                console.log(typeof f);
+            })();
+        })();
+    }
+    expect: {
+        "aaaaaaaaaa";
+        (function a() {
+            (function a() {
+                var o;
+                console.log(typeof a);
+            })();
+        })();
+    }
+    expect_stdout: "function"
+}
+
+issue_3478_1_ie8: {
+    rename = true
+    mangle = {
+        ie8: true,
+        toplevel: false,
+    }
+    input: {
+        "aaaaaaaaaa";
+        (function f() {
+            (function f() {
+                var a;
+                console.log(typeof f);
+            })();
+        })();
+    }
+    expect: {
+        "aaaaaaaaaa";
+        (function f() {
+            (function f() {
+                var a;
+                console.log(typeof f);
+            })();
+        })();
+    }
+    expect_stdout: "function"
+}
+
+issue_3478_1_toplevel: {
+    rename = true
+    mangle = {
+        ie8: false,
+        toplevel: true,
+    }
+    input: {
+        "aaaaaaaaaa";
+        (function f() {
+            (function f() {
+                var a;
+                console.log(typeof f);
+            })();
+        })();
+    }
+    expect: {
+        "aaaaaaaaaa";
+        (function a() {
+            (function a() {
+                var o;
+                console.log(typeof a);
+            })();
+        })();
+    }
+    expect_stdout: "function"
+}
+
+issue_3478_1_ie8_toplevel: {
+    rename = true
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        "aaaaaaaaaa";
+        (function f() {
+            (function f() {
+                var a;
+                console.log(typeof f);
+            })();
+        })();
+    }
+    expect: {
+        "aaaaaaaaaa";
+        (function o() {
+            (function o() {
+                var a;
+                console.log(typeof o);
+            })();
+        })();
+    }
+    expect_stdout: "function"
+}
+
+issue_3478_2: {
+    rename = true
+    mangle = {
+        ie8: false,
+        toplevel: false,
+    }
+    input: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function f() {
+            (function f() {
+                var b = function g() {
+                    f && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function b() {
+            (function n() {
+                var b = function b() {
+                    n && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3478_2_ie8: {
+    rename = true
+    mangle = {
+        ie8: true,
+        toplevel: false,
+    }
+    input: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function f() {
+            (function f() {
+                var b = function g() {
+                    f && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function f() {
+            (function f() {
+                var b = function n() {
+                    f && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3478_2_toplevel: {
+    rename = true
+    mangle = {
+        ie8: false,
+        toplevel: true,
+    }
+    input: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function f() {
+            (function f() {
+                var b = function g() {
+                    f && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect: {
+        "bbbbbbb";
+        var o = "FAIL";
+        (function b() {
+            (function n() {
+                var b = function b() {
+                    n && (o = "PASS");
+                }();
+            })();
+        })();
+        console.log(o);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3478_2_ie8_toplevel: {
+    rename = true
+    mangle = {
+        ie8: true,
+        toplevel: true,
+    }
+    input: {
+        "bbbbbbb";
+        var c = "FAIL";
+        (function f() {
+            (function f() {
+                var b = function g() {
+                    f && (c = "PASS");
+                }();
+            })();
+        })();
+        console.log(c);
+    }
+    expect: {
+        "bbbbbbb";
+        var o = "FAIL";
+        (function c() {
+            (function c() {
+                var b = function n() {
+                    c && (o = "PASS");
+                }();
+            })();
+        })();
+        console.log(o);
+    }
+    expect_stdout: "PASS"
+}