v3.9.4

fixes #3922

.github/workflows/ci.yml

@@ -29,7 +29,7 @@ jobs:
           git clone --branch v1.5.4 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
           while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add $NODE && nvs use $NODE'; do
             cd ~/.nvs
-            git clean -xdf
+            while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
             cd -
           done
           . ~/.nvs/nvs.sh --version

.github/workflows/ufuzz.yml

@@ -1,5 +1,6 @@
 name: Fuzzing
 on:
+  pull_request:
   schedule:
     - cron: "*/8 * * * *"
 jobs:
@@ -18,7 +19,7 @@ jobs:
           git clone --branch v1.5.4 --depth 1 https://github.com/jasongin/nvs.git ~/.nvs
           while ! timeout 60 bash -c '. ~/.nvs/nvs.sh add 10 && nvs use 10'; do
             cd ~/.nvs
-            git clean -xdf
+            while !(git clean -xdf); do echo "'git clean' failed - retrying..."; done
             cd -
           done
           . ~/.nvs/nvs.sh --version

lib/compress.js

@@ -738,8 +738,7 @@ merge(Compressor.prototype, {
                         var value = iife.args[i];
                         d.fixed = function() {
                             var j = fn.argnames.indexOf(arg);
-                            if (j < 0) return value;
-                            return iife.args[j] || make_node(AST_Undefined, iife);
+                            return (j < 0 ? value : iife.args[j]) || make_node(AST_Undefined, iife);
                         };
                         tw.loop_ids[d.id] = tw.in_loop;
                         mark(tw, d, true);
@@ -1302,7 +1301,7 @@ merge(Compressor.prototype, {
                             value_def.replaced++;
                             return List.skip;
                         }
-                        return get_rvalue(candidate);
+                        return rvalue;
                       case 1:
                         if (!assign_used && node.body === candidate) {
                             hit = true;
@@ -1321,7 +1320,7 @@ merge(Compressor.prototype, {
                     if (is_lhs(node, multi_replacer.parent())) return node;
                     def.replaced++;
                     value_def.replaced--;
-                    return get_rvalue(candidate).clone();
+                    return rvalue.clone();
                 }
                 // Skip (non-executed) functions and (leading) default case in switch statements
                 if (node instanceof AST_Default || node instanceof AST_Scope) return node;
@@ -1345,13 +1344,14 @@ merge(Compressor.prototype, {
                     var lhs = get_lhs(candidate);
                     var side_effects = lhs && lhs.has_side_effects(compressor);
                     var scan_lhs = lhs && !side_effects && !is_lhs_read_only(lhs, compressor);
-                    var scan_rhs = foldable(get_rhs(candidate));
+                    var scan_rhs = foldable(candidate);
                     if (!scan_lhs && !scan_rhs) continue;
                     var modify_toplevel = false;
                     // Locate symbols which may execute code outside of scanning range
                     var lvalues = get_lvalues(candidate);
                     var lhs_local = is_lhs_local(lhs);
-                    if (!side_effects) side_effects = value_has_side_effects(candidate);
+                    var rvalue = get_rvalue(candidate);
+                    if (!side_effects) side_effects = value_has_side_effects();
                     var replace_all = replace_all_symbols(candidate);
                     var may_throw = candidate.may_throw(compressor) ? in_try ? function(node) {
                         return node.has_side_effects(compressor);
@@ -1422,6 +1422,7 @@ merge(Compressor.prototype, {
             }
 
             function should_stop(node, parent) {
+                if (node === rvalue) return true;
                 if (parent instanceof AST_For) return node !== parent.init;
                 if (node instanceof AST_Assign) {
                     return node.operator != "=" && lhs.equivalent_to(node.left);
@@ -1429,8 +1430,7 @@ merge(Compressor.prototype, {
                 if (node instanceof AST_Call) {
                     if (!(lhs instanceof AST_PropAccess)) return false;
                     if (!lhs.equivalent_to(node.expression)) return false;
-                    var rhs = get_rvalue(candidate);
-                    return !(rhs instanceof AST_Function && !rhs.contains_this());
+                    return !(rvalue instanceof AST_Function && !rvalue.contains_this());
                 }
                 if (node instanceof AST_Debugger) return true;
                 if (node instanceof AST_Defun) return funarg && lhs.name === node.name.name;
@@ -1836,10 +1836,6 @@ merge(Compressor.prototype, {
                 }
             }
 
-            function get_rhs(expr) {
-                return candidate instanceof AST_Assign && candidate.operator == "=" && candidate.right;
-            }
-
             function invariant(expr) {
                 if (expr instanceof AST_Array) return false;
                 if (expr instanceof AST_Binary && lazy_op[expr.operator]) {
@@ -1854,7 +1850,14 @@ merge(Compressor.prototype, {
             }
 
             function foldable(expr) {
-                if (!expr) return false;
+                var lhs_ids = Object.create(null);
+                var marker = new TreeWalker(function(node) {
+                    if (node instanceof AST_SymbolRef) lhs_ids[node.definition().id] = true;
+                });
+                while (expr instanceof AST_Assign && expr.operator == "=") {
+                    expr.left.walk(marker);
+                    expr = expr.right;
+                }
                 if (expr instanceof AST_SymbolRef) {
                     var value = expr.evaluate(compressor);
                     if (value === expr) return rhs_exact_match;
@@ -1868,12 +1871,9 @@ merge(Compressor.prototype, {
                 if (!(lhs instanceof AST_SymbolRef)) return false;
                 if (!invariant(expr)) return false;
                 var circular;
-                var def = lhs.definition();
                 expr.walk(new TreeWalker(function(node) {
                     if (circular) return true;
-                    if (node instanceof AST_SymbolRef && node.definition() === def) {
-                        circular = true;
-                    }
+                    if (node instanceof AST_SymbolRef && lhs_ids[node.definition().id]) circular = true;
                 }));
                 return !circular && rhs_exact_match;
 
@@ -1969,9 +1969,9 @@ merge(Compressor.prototype, {
                             || candidate instanceof AST_Assign && candidate.operator != "="));
             }
 
-            function value_has_side_effects(expr) {
-                if (expr instanceof AST_Unary) return false;
-                return get_rvalue(expr).has_side_effects(compressor);
+            function value_has_side_effects() {
+                if (candidate instanceof AST_Unary) return false;
+                return rvalue.has_side_effects(compressor);
             }
 
             function replace_all_symbols(expr) {
@@ -2507,7 +2507,7 @@ merge(Compressor.prototype, {
                 }
                 if (prop instanceof AST_Node) break;
                 prop = "" + prop;
-                var diff = compressor.has_directive("use strict") ? function(node) {
+                var diff = prop == "__proto__" || compressor.has_directive("use strict") ? function(node) {
                     return node.key != prop && node.key.name != prop;
                 } : function(node) {
                     return node.key.name != prop;
@@ -3255,11 +3255,21 @@ merge(Compressor.prototype, {
                     && unaryPrefix[this.operator];
             }
         });
-        function modified(sym) {
-            if (!(sym instanceof AST_SymbolRef)) return;
-            sym.definition().references.forEach(function(node) {
-                delete node._eval;
-            });
+        var scan_modified = new TreeWalker(function(node) {
+            if (node instanceof AST_Assign) modified(node.left);
+            if (node instanceof AST_Unary && unary_arithmetic[node.operator]) modified(node.expression);
+        });
+        function modified(node) {
+            if (node instanceof AST_Dot) {
+                modified(node.expression);
+            } else if (node instanceof AST_Sub) {
+                modified(node.expression);
+                node.property.walk(scan_modified);
+            } else if (node instanceof AST_SymbolRef) {
+                node.definition().references.forEach(function(ref) {
+                    delete ref._eval;
+                });
+            }
         }
         def(AST_Statement, function() {
             throw new Error(string_template("Cannot evaluate a statement [{file}:{line},{col}]", this.start));
@@ -3279,12 +3289,11 @@ merge(Compressor.prototype, {
         });
         def(AST_Sequence, function(compressor, ignore_side_effects, cached, depth) {
             if (!ignore_side_effects) return this;
-            var tail = this.tail_node();
-            this.walk(new TreeWalker(function(node) {
-                if (node === tail) return true;
-                if (node instanceof AST_Assign) modified(node.left);
-                if (node instanceof AST_Unary && unary_arithmetic[node.operator]) modified(node.expression);
-            }));
+            var exprs = this.expressions;
+            for (var i = 0, last = exprs.length - 1; i < last; i++) {
+                exprs[i].walk(scan_modified);
+            }
+            var tail = exprs[last];
             var value = tail._eval(compressor, ignore_side_effects, cached, depth);
             return value === tail ? this : value;
         });
@@ -3565,8 +3574,10 @@ merge(Compressor.prototype, {
                 }
                 var args = eval_args(this.args);
                 if (!args && !ignore_side_effects) return this;
-                if (!stat.value) return;
-                if (args && !all(fn.argnames, function(sym, i) {
+                var val = stat.value;
+                if (!val) return;
+                var cached_args = [];
+                if (!args || all(fn.argnames, function(sym, i) {
                     var value = args[i];
                     var def = sym.definition();
                     if (def.orig[def.orig.length - 1] !== sym) return false;
@@ -3574,15 +3585,18 @@ merge(Compressor.prototype, {
                         node._eval = function() {
                             return value;
                         };
-                        cached.push(node);
+                        cached_args.push(node);
                     });
                     return true;
-                }) && !ignore_side_effects) return this;
-                fn.evaluating = true;
-                var val = stat.value._eval(compressor, ignore_side_effects, cached, depth);
-                delete fn.evaluating;
-                if (val === stat.value) return this;
-                return val;
+                }) || ignore_side_effects) {
+                    fn.evaluating = true;
+                    val = val._eval(compressor, ignore_side_effects, cached, depth);
+                    delete fn.evaluating;
+                }
+                cached_args.forEach(function(node) {
+                    delete node._eval;
+                });
+                return val === stat.value ? this : val;
             } else if (compressor.option("unsafe") && exp instanceof AST_PropAccess) {
                 var key = exp.property;
                 if (key instanceof AST_Node) {
@@ -4358,6 +4372,7 @@ merge(Compressor.prototype, {
                         } else if (compressor.option("functions")
                             && !compressor.option("ie8")
                             && var_defs.length == 1
+                            && sym.assignments == 0
                             && def.value === def.name.fixed_value()
                             && def.value instanceof AST_Function
                             && !(def.value.name && def.value.name.definition().assignments)
@@ -6227,9 +6242,9 @@ merge(Compressor.prototype, {
                 && !fn.uses_arguments
                 && !fn.pinned()
                 && !(fn.name && fn instanceof AST_Function)
-                && (value = can_flatten_body(stat))
                 && (exp === fn
                     || !recursive_ref(compressor, def = exp.definition()) && fn.is_constant_expression(exp.scope))
+                && (value = can_flatten_body(stat))
                 && !fn.contains_this()) {
                 if (can_substitute_directly()) {
                     var args = self.args.slice();
@@ -7508,6 +7523,8 @@ merge(Compressor.prototype, {
                                 scope.inlined = true;
                             } while (scope = scope.parent_scope);
                         }
+                    } else if (compressor.option("ie8") && fixed.name && def !== fixed.name.definition()) {
+                        single_use = false;
                     }
                     if (single_use) fixed.parent_scope = self.scope;
                 } else if (!fixed || !fixed.is_constant_expression()) {
@@ -7566,6 +7583,12 @@ merge(Compressor.prototype, {
                     }));
                 } else {
                     value = fixed.optimize(compressor);
+                    if (value === fixed) value = value.transform(new TreeTransformer(function(node, descend) {
+                        if (node instanceof AST_Scope) return node;
+                        node = node.clone();
+                        descend(node, this);
+                        return node;
+                    }));
                 }
                 def.replaced++;
                 return value;
@@ -7727,6 +7750,10 @@ merge(Compressor.prototype, {
         if (compressor.option("dead_code")) {
             if (self.left instanceof AST_PropAccess) {
                 if (self.operator == "=") {
+                    if (self.left.equivalent_to(self.right)
+                        && (self.left instanceof AST_Dot || !self.left.property.has_side_effects(compressor))) {
+                        return self.right;
+                    }
                     var exp = self.left.expression;
                     if (exp instanceof AST_Lambda
                         || !compressor.has_directive("use strict")
@@ -7739,6 +7766,7 @@ merge(Compressor.prototype, {
                     }
                 }
             } else if (self.left instanceof AST_SymbolRef) {
+                if (self.operator == "=" && self.left.equivalent_to(self.right)) return self.right;
                 if (self.left.is_immutable()) return strip_assignment();
                 var def = self.left.definition();
                 var scope = def.scope.resolve();

package.json

@@ -3,7 +3,7 @@
   "description": "JavaScript parser, mangler/compressor and beautifier toolkit",
   "author": "Mihai Bazon <mihai.bazon@gmail.com> (http://lisperator.net/)",
   "license": "BSD-2-Clause",
-  "version": "3.9.3",
+  "version": "3.9.4",
   "engines": {
     "node": ">=0.8.0"
   },

test/benchmark.js

@@ -10,7 +10,7 @@ var zlib = require("zlib");
 var args = process.argv.slice(2);
 if (!args.length) args.push("-mc");
 args.unshift("bin/uglifyjs");
-args.push("--validate", "--timings");
+args.push("--timings");
 var urls = [
     "https://code.jquery.com/jquery-3.4.1.js",
     "https://code.angularjs.org/1.7.8/angular.js",

test/compress/collapse_vars.js

@@ -8015,3 +8015,96 @@ issue_3891: {
     }
     expect_stdout: "function"
 }
+
+issue_3894: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function log(msg) {
+            console.log(msg ? "FAIL" : "PASS");
+        }
+        var a, c;
+        (function(b) {
+            a = c = 0,
+            log(b);
+        })(-0);
+        log(a);
+        log(c);
+    }
+    expect: {
+        function log(msg) {
+            console.log(msg ? "FAIL" : "PASS");
+        }
+        var a, c;
+        void log(-(a = c = 0));
+        log(a);
+        log(c);
+    }
+    expect_stdout: [
+        "PASS",
+        "PASS",
+        "PASS",
+    ]
+}
+
+issue_3897: {
+    options = {
+        collapse_vars: true,
+    }
+    input: {
+        var a = 0;
+        (function() {
+            function f(b) {
+                b = a = 1 + a;
+                a = 1 + a;
+                console.log(b);
+            }
+            f();
+        })();
+        console.log(a);
+    }
+    expect: {
+        var a = 0;
+        (function() {
+            function f(b) {
+                b = a = 1 + a;
+                a = 1 + a;
+                console.log(b);
+            }
+            f();
+        })();
+        console.log(a);
+    }
+    expect_stdout: [
+        "1",
+        "2",
+    ]
+}
+
+issue_3908: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        if (console) {
+            var o = {
+                p: !1
+            }, a = o;
+        }
+        console.log("PASS");
+    }
+    expect: {
+        console && 0;
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}

test/compress/dead-code.js

@@ -1168,3 +1168,28 @@ redundant_assignments: {
     }
     expect_stdout: "PASS PASS"
 }
+
+self_assignments: {
+    options = {
+        dead_code: true,
+    }
+    input: {
+        var a = "PASS", b = 0, l = [ "FAIL", "PASS" ], o = { p: "PASS" };
+        a = a;
+        l[0] = l[0];
+        l[b] = l[b];
+        l[b++] = l[b++];
+        o.p = o.p;
+        console.log(a, b, l[0], o.p);
+    }
+    expect: {
+        var a = "PASS", b = 0, l = [ "FAIL", "PASS" ], o = { p: "PASS" };
+        a;
+        l[0];
+        l[b];
+        l[b++] = l[b++];
+        o.p;
+        console.log(a, b, l[0], o.p);
+    }
+    expect_stdout: "PASS 2 PASS PASS"
+}

test/compress/drop-unused.js

@@ -2527,7 +2527,40 @@ issue_3802_2: {
     }
     expect: {
         0;
-        function a() {};
+        var a = function() {};
+        console.log(typeof a);
+    }
+    expect_stdout: "function"
+}
+
+issue_3899: {
+    options = {
+        assignments: true,
+        evaluate: true,
+        functions: true,
+        inline: true,
+        join_vars: true,
+        passes: 2,
+        reduce_vars: true,
+        side_effects: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = 0;
+        a = a + 1;
+        var a = function f(b) {
+            return function() {
+                return b;
+            };
+        }(2);
+        console.log(typeof a);
+    }
+    expect: {
+        ++a;
+        var a = function() {
+            return 2;
+        };
         console.log(typeof a);
     }
     expect_stdout: "function"

test/compress/evaluate.js

@@ -2418,3 +2418,70 @@ issue_3887: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3903: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = "PASS";
+        function f(b, c) {
+            return console, c;
+        }
+        var d = f(f(), a = a);
+        console.log(d);
+    }
+    expect: {
+        var a = "PASS";
+        function f(b, c) {
+            return console, c;
+        }
+        var d = f(f(), a = a);
+        console.log(d);
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3905: {
+    options = {
+        evaluate: true,
+        passes: 2,
+        unused: true,
+    }
+    input: {
+        (function(a, a) {
+            return console.log(a = 0), a && console.log("FAIL");
+        })("foo", 42);
+    }
+    expect: {
+        (function(a, a) {
+            return console.log(a = 0), a && console.log("FAIL");
+        })("foo", 42);
+    }
+    expect_stdout: "0"
+}
+
+issue_3920: {
+    options = {
+        evaluate: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        var a = function(b) {
+            return (b[b = 0] = 0) >= (b ? 0 : 1);
+        }("foo");
+        console.log(a);
+    }
+    expect: {
+        var a = function(b) {
+            return (b[b = 0] = 0) >= (b ? 0 : 1);
+        }("foo");
+        console.log(a);
+    }
+    expect_stdout: "false"
+}

test/compress/functions.js

@@ -4680,3 +4680,28 @@ issue_3852: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3911: {
+    options = {
+        collapse_vars: true,
+        conditionals: true,
+        inline: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    input: {
+        function f() {
+            return function() {
+                if (a) (a++, b += a);
+                f();
+            };
+        }
+        var a = f, b;
+        console.log("PASS");
+    }
+    expect: {
+        console.log("PASS");
+    }
+    expect_stdout: "PASS"
+}

test/compress/ie8.js

@@ -2489,3 +2489,36 @@ issue_3889: {
     }
     expect_stdout: "undefined"
 }
+
+issue_3918: {
+    options = {
+        conditionals: true,
+        ie8: true,
+        reduce_vars: true,
+        toplevel: true,
+        unused: true,
+    }
+    mangle = {
+        ie8: true,
+    }
+    input: {
+        if (console.log("PASS")) {
+            var a = function f() {
+                f.p;
+                try {
+                    console.log("FAIL");
+                } catch (e) {}
+            }, b = a;
+        }
+    }
+    expect: {
+        var a;
+        console.log("PASS") && (a = function f() {
+            f.p;
+            try {
+                console.log("FAIL");
+            } catch (o) {}
+        }, a);
+    }
+    expect_stdout: "PASS"
+}

test/compress/join_vars.js

@@ -1023,3 +1023,35 @@ issue_3856: {
     }
     expect_stdout: "undefined"
 }
+
+issue_3916: {
+    options = {
+        join_vars: true,
+    }
+    input: {
+        var o = {};
+        o.p = "PASS";
+        o.__proto__ = 42;
+        o.q = "FAIL";
+        o.__proto__ = {
+            p: "FAIL",
+            q: "PASS",
+        };
+        o.__proto__ = "foo";
+        console.log(typeof o.__proto__, o.p, delete o.q, o.q);
+    }
+    expect: {
+        var o = {
+            p: "PASS",
+            __proto__: 42,
+            q: "FAIL",
+        };
+        o.__proto__ = {
+            p: "FAIL",
+            q: "PASS",
+        };
+        o.__proto__ = "foo";
+        console.log(typeof o.__proto__, o.p, delete o.q, o.q);
+    }
+    expect_stdout: "object PASS true PASS"
+}

test/compress/reduce_vars.js

@@ -7068,3 +7068,57 @@ issue_3880: {
     }
     expect_stdout: "PASS"
 }
+
+issue_3894: {
+    options = {
+        collapse_vars: true,
+        inline: true,
+        reduce_vars: true,
+        unused: true,
+    }
+    input: {
+        function log(msg) {
+            console.log(msg ? "FAIL" : "PASS");
+        }
+        var a;
+        (function(b) {
+            a = 0,
+            log(b);
+        })(-0);
+    }
+    expect: {
+        function log(msg) {
+            console.log(msg ? "FAIL" : "PASS");
+        }
+        var a;
+        void log(-(a = 0));
+    }
+    expect_stdout: "PASS"
+}
+
+issue_3922: {
+    options = {
+        evaluate: true,
+        keep_fargs: "strict",
+        pure_getters: "strict",
+        reduce_vars: true,
+        side_effects: true,
+        unused: true,
+    }
+    input: {
+        (function(a) {
+            var b;
+            b && b[c];
+            a |= this;
+            console.log("PASS");
+            var c = a.undefined;
+        })();
+    }
+    expect: {
+        (function() {
+            0;
+            console.log("PASS");
+        })();
+    }
+    expect_stdout: "PASS"
+}

test/reduce.js

@@ -4,19 +4,17 @@ var List = U.List;
 var os = require("os");
 var sandbox = require("./sandbox");
 
-// Reduce a ufuzz-style `console.log` based test case by iteratively replacing
-// AST nodes with various permutations. Each AST_Statement in the tree is also
-// speculatively dropped to determine whether it is needed.  If the altered
-// tree and the last known good tree produce the same non-nil error-free output
-// after being run, then the permutation survives to the next generation and
-// is the basis for subsequent iterations.  The test case is reduced as a
-// consequence of complex expressions being replaced with simpler ones.
-// This function assumes that the testcase will not result in a parse or
-// runtime Error.  Note that a reduced test case will have different runtime
-// output - it is not functionally equivalent to the original. The only criteria
-// is that once the generated reduced test case is run without minification, it
-// will produce different output from the code minified with `minify_options`.
-// Returns a `minify` result object with an additonal boolean property `reduced`.
+// Reduce a test case by iteratively replacing AST nodes with various
+// permutations. Each AST_Statement in the tree is also speculatively dropped
+// to determine whether it is needed.  If the altered tree and the last known
+// good tree produce the same output after being run, then the permutation
+// survives to the next generation and is the basis for subsequent iterations.
+// The test case is reduced as a consequence of complex expressions being
+// replaced with simpler ones.  Note that a reduced test case will have
+// different runtime output - it is not functionally equivalent to the
+// original. The only criteria is that once the generated reduced test case is
+// run without minification, it will produce different output from the code
+// minified with `minify_options`.  Returns a `minify` result object.
 
 Error.stackTraceLimit = Infinity;
 module.exports = function reduce_test(testcase, minify_options, reduce_options) {

test/release/benchmark.js

@@ -9,6 +9,6 @@ require("./run")([
     "-mc keep_fargs=false,passes=3,pure_getters,unsafe,unsafe_comps,unsafe_math,unsafe_proto",
 ].map(function(options) {
     var args = options.split(/ /);
-    args.unshift("test/benchmark.js");
+    args.unshift("test/benchmark.js", "--validate");
     return args;
 }));

test/ufuzz/index.js

@@ -1018,6 +1018,7 @@ function log_suspects(minify_options, component) {
     if (!options) return;
     if (typeof options != "object") options = {};
     var defs = default_options[component];
+    var toplevel = sandbox.has_toplevel(minify_options);
     var suspects = Object.keys(defs).filter(function(name) {
         var flip = name == "keep_fargs";
         if (flip !== (name in options ? options : defs)[name]) {
@@ -1025,12 +1026,15 @@ function log_suspects(minify_options, component) {
             var o = JSON.parse(JSON.stringify(options));
             o[name] = flip;
             m[component] = o;
+            m.validate = true;
             var result = UglifyJS.minify(original_code, m);
-            if (result.error) {
+            if (typeof uglify_code != "string") {
+                return !sandbox.same_stdout(uglify_code, result.error);
+            } else if (result.error) {
                 errorln("Error testing options." + component + "." + name);
                 errorln(result.error);
             } else {
-                var r = sandbox.run_code(result.code, sandbox.has_toplevel(m));
+                var r = sandbox.run_code(result.code, toplevel);
                 return !sandbox.same_stdout(uglify_result, r);
             }
         }
@@ -1044,18 +1048,21 @@ function log_suspects(minify_options, component) {
     }
 }
 
-function log_suspects_global(options) {
+function log_suspects_global(options, toplevel) {
     var suspects = Object.keys(default_options).filter(function(component) {
       return typeof default_options[component] != "object";
     }).filter(function(component) {
         var m = JSON.parse(options);
         m[component] = false;
+        m.validate = true;
         var result = UglifyJS.minify(original_code, m);
-        if (result.error) {
+        if (typeof uglify_code != "string") {
+            return !sandbox.same_stdout(uglify_code, result.error);
+        } else if (result.error) {
             errorln("Error testing options." + component);
             errorln(result.error);
         } else {
-            var r = sandbox.run_code(result.code, sandbox.has_toplevel(m));
+            var r = sandbox.run_code(result.code, toplevel);
             return !sandbox.same_stdout(uglify_result, r);
         }
     });
@@ -1074,7 +1081,37 @@ function log(options) {
     errorln("//=============================================================");
     if (!ok) errorln("// !!!!!! Failed... round " + round);
     errorln("// original code");
-    try_beautify(original_code, toplevel, original_result, errorln);
+    var beautified = UglifyJS.minify(original_code, {
+        compress: false,
+        mangle: false,
+        output: {
+            beautify: true,
+            braces: true,
+        },
+    });
+    if (beautified.error) {
+        errorln("// !!! beautify failed !!!");
+        errorln(beautified.error);
+        errorln("//");
+        errorln(original_code);
+    } else {
+        var uglified = UglifyJS.minify(beautified.code, JSON.parse(options));
+        var expected, actual;
+        if (typeof uglify_code != "string" || uglified.error) {
+            expected = uglify_code;
+            actual = uglified.error;
+        } else {
+            expected = uglify_result;
+            actual = sandbox.run_code(uglified.code, toplevel);
+        }
+        if (sandbox.same_stdout(expected, actual)) {
+            errorln("// (beautified)");
+            errorln(beautified.code);
+        } else {
+            errorln("//");
+            errorln(original_code);
+        }
+    }
     errorln();
     errorln();
     errorln("//-------------------------------------------------------------");
@@ -1112,12 +1149,12 @@ function log(options) {
     errorln("minify(options):");
     errorln(JSON.stringify(JSON.parse(options), null, 2));
     errorln();
-    if (!ok && typeof uglify_code == "string") {
+    if (!ok) {
         Object.keys(default_options).filter(function(component) {
           var defs = default_options[component];
           return defs && typeof defs == "object";
         }).forEach(log_suspects.bind(null, JSON.parse(options)));
-        log_suspects_global(options);
+        log_suspects_global(options, toplevel);
         errorln("!!!!!! Failed... round " + round);
     }
 }
@@ -1140,19 +1177,19 @@ function skip_infinite_recursion(orig, toplevel) {
     var code = orig;
     var tries = [];
     var offset = 0;
-    var re = /(?:(?:^|[\s{};])try|}\s*catch\s*\(([^)]+)\)|}\s*finally)\s*(?={)/g;
+    var re = /(?:(?:^|[\s{}):;])try|}\s*catch\s*\(([^)]+)\)|}\s*finally)\s*(?={)/g;
     var match;
     while (match = re.exec(code)) {
         if (/}\s*finally\s*$/.test(match[0])) {
             tries.shift();
             continue;
         }
-        if (tries.length && tries[0].catch) tries.shift();
         var index = match.index + match[0].length + 1;
-        if (/(?:^|[\s{};])try\s*$/.test(match[0])) {
+        if (/(?:^|[\s{}):;])try\s*$/.test(match[0])) {
             tries.unshift({ try: index - offset });
             continue;
         }
+        while (tries.length && tries[0].catch) tries.shift();
         tries[0].catch = index;
         var insert = "throw " + match[1] + ".ufuzz_skip || (" + match[1] + ".ufuzz_skip = " + tries[0].try + "), " + match[1] + ";";
         var new_code = code.slice(0, index) + insert + code.slice(index);