improve parser under "use strict"

- `const` without value
- `delete` of expression
- redefining `arguments` or `eval`

fixes #1810

lib/parse.js

@@ -629,8 +629,7 @@ function tokenizer($TEXT, filename, html5_comments, shebang) {
     }
 
     next_token.has_directive = function(directive) {
-        return S.directives[directive] !== undefined &&
+        return S.directives[directive] > 0;
-            S.directives[directive] > 0;
     }
 
     return next_token;
@@ -1033,29 +1032,32 @@ function parse($TEXT, options) {
         if (in_statement && !name)
             unexpected();
         expect("(");
+        var argnames = [];
+        for (var first = true; !is("punc", ")");) {
+            if (first) first = false; else expect(",");
+            argnames.push(as_symbol(AST_SymbolFunarg));
+        }
+        next();
+        var loop = S.in_loop;
+        var labels = S.labels;
+        ++S.in_function;
+        S.in_directives = true;
+        S.input.push_directives_stack();
+        S.in_loop = 0;
+        S.labels = [];
+        var body = block_();
+        if (S.input.has_directive("use strict")) {
+            if (name) strict_verify_symbol(name);
+            argnames.forEach(strict_verify_symbol);
+        }
+        S.input.pop_directives_stack();
+        --S.in_function;
+        S.in_loop = loop;
+        S.labels = labels;
         return new ctor({
             name: name,
-            argnames: (function(first, a){
+            argnames: argnames,
-                while (!is("punc", ")")) {
+            body: body
-                    if (first) first = false; else expect(",");
-                    a.push(as_symbol(AST_SymbolFunarg));
-                }
-                next();
-                return a;
-            })(true, []),
-            body: (function(loop, labels){
-                ++S.in_function;
-                S.in_directives = true;
-                S.input.push_directives_stack();
-                S.in_loop = 0;
-                S.labels = [];
-                var a = block_();
-                S.input.pop_directives_stack();
-                --S.in_function;
-                S.in_loop = loop;
-                S.labels = labels;
-                return a;
-            })(S.in_loop, S.labels)
         });
     };
 
@@ -1157,7 +1159,10 @@ function parse($TEXT, options) {
             a.push(new AST_VarDef({
                 start : S.token,
                 name  : as_symbol(in_const ? AST_SymbolConst : AST_SymbolVar),
-                value : is("operator", "=") ? (next(), expression(false, no_in)) : null,
+                value : is("operator", "=")
+                    ? (next(), expression(false, no_in))
+                    : in_const && S.input.has_directive("use strict")
+                        ? croak("Missing initializer in const declaration") : null,
                 end   : prev()
             }));
             if (!is("punc", ","))
@@ -1384,12 +1389,20 @@ function parse($TEXT, options) {
         });
     };
 
+    function strict_verify_symbol(sym) {
+        if (sym.name == "arguments" || sym.name == "eval")
+            croak("Unexpected " + sym.name + " in strict mode", sym.start.line, sym.start.col, sym.start.pos);
+    }
+
     function as_symbol(type, noerror) {
         if (!is("name")) {
             if (!noerror) croak("Name expected");
             return null;
         }
         var sym = _make_symbol(type);
+        if (S.input.has_directive("use strict") && sym instanceof AST_SymbolDeclaration) {
+            strict_verify_symbol(sym);
+        }
         next();
         return sym;
     };
@@ -1450,8 +1463,17 @@ function parse($TEXT, options) {
 
     function make_unary(ctor, token, expr) {
         var op = token.value;
-        if ((op == "++" || op == "--") && !is_assignable(expr))
+        switch (op) {
-            croak("Invalid use of " + op + " operator", token.line, token.col, token.pos);
+          case "++":
+          case "--":
+            if (!is_assignable(expr))
+                croak("Invalid use of " + op + " operator", token.line, token.col, token.pos);
+            break;
+          case "delete":
+            if (!(expr instanceof AST_PropAccess) && S.input.has_directive("use strict"))
+                croak("Calling delete on expression not allowed in strict mode", expr.start.line, expr.start.col, expr.start.pos);
+            break;
+        }
         return new ctor({ operator: op, expression: expr });
     };
 

test/input/invalid/const.js

@@ -0,0 +1,8 @@
+function f() {
+    const a;
+}
+
+function g() {
+    "use strict";
+    const a;
+}

test/input/invalid/delete.js

@@ -0,0 +1,8 @@
+function f(x) {
+    delete x;
+}
+
+function g(x) {
+    "use strict";
+    delete x;
+}

test/input/invalid/function_1.js

@@ -0,0 +1,6 @@
+function f(arguments) {
+}
+
+function g(arguments) {
+    "use strict";
+}

test/input/invalid/function_2.js

@@ -0,0 +1,6 @@
+function arguments() {
+}
+
+function eval() {
+    "use strict";
+}

test/input/invalid/function_3.js

@@ -0,0 +1,6 @@
+!function eval() {
+}();
+
+!function arguments() {
+    "use strict";
+}();

test/input/invalid/try.js

@@ -0,0 +1,8 @@
+function f() {
+    try {} catch (eval) {}
+}
+
+function g() {
+    "use strict";
+    try {} catch (eval) {}
+}

test/input/invalid/var.js

@@ -0,0 +1,8 @@
+function f() {
+    var eval;
+}
+
+function g() {
+    "use strict";
+    var eval;
+}

test/mocha/cli.js

@@ -379,6 +379,111 @@ describe("bin/uglifyjs", function () {
            done();
        });
     });
+    it("Should throw syntax error (const a)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/const.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/const.js:7,11",
+               "    const a;",
+               "           ^",
+               "ERROR: Missing initializer in const declaration"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (delete x)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/delete.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/delete.js:7,11",
+               "    delete x;",
+               "           ^",
+               "ERROR: Calling delete on expression not allowed in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (function g(arguments))", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/function_1.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/function_1.js:4,11",
+               "function g(arguments) {",
+               "           ^",
+               "ERROR: Unexpected arguments in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (function eval())", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/function_2.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/function_2.js:4,9",
+               "function eval() {",
+               "         ^",
+               "ERROR: Unexpected eval in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (iife arguments())", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/function_3.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/function_3.js:4,10",
+               "!function arguments() {",
+               "          ^",
+               "ERROR: Unexpected arguments in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (catch(eval))", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/try.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/try.js:7,18",
+               "    try {} catch (eval) {}",
+               "                  ^",
+               "ERROR: Unexpected eval in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
+    it("Should throw syntax error (var eval)", function(done) {
+       var command = uglifyjscmd + ' test/input/invalid/var.js';
+
+       exec(command, function (err, stdout, stderr) {
+           assert.ok(err);
+           assert.strictEqual(stdout, "");
+           assert.strictEqual(stderr.split(/\n/).slice(0, 4).join("\n"), [
+               "Parse error at test/input/invalid/var.js:7,8",
+               "    var eval;",
+               "        ^",
+               "ERROR: Unexpected eval in strict mode"
+           ].join("\n"));
+           done();
+       });
+    });
     it("Should handle literal string as source map input", function(done) {
         var command = [
             uglifyjscmd,