improve keyword-related parser errors (#1941)

fixes #1937

test/mocha/cli.js

@@ -55,15 +55,15 @@ describe("bin/uglifyjs", function () {
         });
     });
     it("Should append source map to output when using --source-map url=inline", function (done) {
-       var command = uglifyjscmd + " test/input/issue-1323/sample.js --source-map url=inline";
+        var command = uglifyjscmd + " test/input/issue-1323/sample.js --source-map url=inline";
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "var bar=function(){function foo(bar){return bar}return foo}();\n" +
-               "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxHQUFJQSxLQUFNLFdBQ04sUUFBU0MsS0FBS0QsS0FDVixNQUFPQSxLQUdYLE1BQU9DIn0=\n");
-           done();
-       });
+            assert.strictEqual(stdout, "var bar=function(){function foo(bar){return bar}return foo}();\n" +
+                "//# sourceMappingURL=data:application/json;charset=utf-8;base64,eyJ2ZXJzaW9uIjozLCJzb3VyY2VzIjpbInRlc3QvaW5wdXQvaXNzdWUtMTMyMy9zYW1wbGUuanMiXSwibmFtZXMiOlsiYmFyIiwiZm9vIl0sIm1hcHBpbmdzIjoiQUFBQSxHQUFJQSxLQUFNLFdBQ04sUUFBU0MsS0FBS0QsS0FDVixNQUFPQSxLQUdYLE1BQU9DIn0=\n");
+            done();
+        });
     });
     it("should not append source map to output when not using --source-map url=inline", function (done) {
         var command = uglifyjscmd + ' test/input/issue-1323/sample.js';
@@ -76,84 +76,84 @@ describe("bin/uglifyjs", function () {
         });
     });
     it("Should work with --keep-fnames (mangle only)", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m';
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
-           done();
-       });
+            assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
+            done();
+        });
     });
     it("Should work with --keep-fnames (mangle & compress)", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c unused=false';
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js --keep-fnames -m -c unused=false';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(5==f(g)());\n");
-           done();
-       });
+            assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(5==f(g)());\n");
+            done();
+        });
     });
     it("Should work with keep_fnames under mangler options", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1431/sample.js -m keep_fnames=true';
+        var command = uglifyjscmd + ' test/input/issue-1431/sample.js -m keep_fnames=true';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
-           done();
-       });
+            assert.strictEqual(stdout, "function f(r){return function(){function n(n){return n*n}return r(n)}}function g(n){return n(1)+n(2)}console.log(f(g)()==5);\n");
+            done();
+        });
     });
     it("Should work with --define (simple)", function (done) {
-       var command = uglifyjscmd + ' test/input/global_defs/simple.js --define D=5 -c';
+        var command = uglifyjscmd + ' test/input/global_defs/simple.js --define D=5 -c';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "console.log(5);\n");
-           done();
-       });
+            assert.strictEqual(stdout, "console.log(5);\n");
+            done();
+        });
     });
     it("Should work with --define (nested)", function (done) {
-       var command = uglifyjscmd + ' test/input/global_defs/nested.js --define C.D=5,C.V=3 -c';
+        var command = uglifyjscmd + ' test/input/global_defs/nested.js --define C.D=5,C.V=3 -c';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "console.log(3,5);\n");
-           done();
-       });
+            assert.strictEqual(stdout, "console.log(3,5);\n");
+            done();
+        });
     });
     it("Should work with --define (AST_Node)", function (done) {
-       var command = uglifyjscmd + ' test/input/global_defs/simple.js --define console.log=stdout.println -c';
+        var command = uglifyjscmd + ' test/input/global_defs/simple.js --define console.log=stdout.println -c';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, "stdout.println(D);\n");
-           done();
-       });
+            assert.strictEqual(stdout, "stdout.println(D);\n");
+            done();
+        });
     });
     it("Should work with `--beautify`", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1482/input.js -b';
+        var command = uglifyjscmd + ' test/input/issue-1482/input.js -b';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, read("test/input/issue-1482/default.js"));
-           done();
-       });
+            assert.strictEqual(stdout, read("test/input/issue-1482/default.js"));
+            done();
+        });
     });
     it("Should work with `--beautify bracketize`", function (done) {
-       var command = uglifyjscmd + ' test/input/issue-1482/input.js -b bracketize';
+        var command = uglifyjscmd + ' test/input/issue-1482/input.js -b bracketize';
 
-       exec(command, function (err, stdout) {
-           if (err) throw err;
+        exec(command, function (err, stdout) {
+            if (err) throw err;
 
-           assert.strictEqual(stdout, read("test/input/issue-1482/bracketize.js"));
-           done();
-       });
+            assert.strictEqual(stdout, read("test/input/issue-1482/bracketize.js"));
+            done();
+        });
     });
     it("Should process inline source map", function(done) {
         var command = uglifyjscmd + " test/input/issue-520/input.js -mc toplevel --source-map content=inline,url=inline";
@@ -260,214 +260,244 @@ describe("bin/uglifyjs", function () {
         });
     });
     it("Should throw syntax error (5--)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/assign_1.js';
+        var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_1.js:1,18",
-               "console.log(1 || 5--);",
-               "                  ^",
-               "ERROR: Invalid use of -- operator"
-           ].join("\n"));
-           done();
-       });
+        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/assign_1.js:1,18",
+                "console.log(1 || 5--);",
+                "                  ^",
+                "ERROR: Invalid use of -- operator"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (Math.random() /= 2)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/assign_2.js';
+        var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_2.js:1,32",
-               "console.log(2 || (Math.random() /= 2));",
-               "                                ^",
-               "ERROR: Invalid assignment"
-           ].join("\n"));
-           done();
-       });
+        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/assign_2.js:1,32",
+                "console.log(2 || (Math.random() /= 2));",
+                "                                ^",
+                "ERROR: Invalid assignment"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (++this)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/assign_3.js';
+        var command = uglifyjscmd + ' test/input/invalid/assign_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/assign_3.js:1,17",
-               "console.log(3 || ++this);",
-               "                 ^",
-               "ERROR: Invalid use of ++ operator"
-           ].join("\n"));
-           done();
-       });
+        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/assign_3.js:1,17",
+                "console.log(3 || ++this);",
+                "                 ^",
+                "ERROR: Invalid use of ++ operator"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (++null)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/assign_4.js';
+        var command = uglifyjscmd + ' test/input/invalid/assign_4.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/assign_4.js:1,0",
-               "++null",
-               "^",
-               "ERROR: Invalid use of ++ operator"
-           ].join("\n"));
-           done();
-       });
+        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/assign_4.js:1,0",
+                "++null",
+                "^",
+                "ERROR: Invalid use of ++ operator"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (a.=)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/dot_1.js';
+        var command = uglifyjscmd + ' test/input/invalid/dot_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/dot_1.js:1,2",
-               "a.=",
-               "  ^",
-               "ERROR: Unexpected token: operator (=)"
-           ].join("\n"));
-           done();
-       });
+        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/dot_1.js:1,2",
+                "a.=",
+                "  ^",
+                "ERROR: Unexpected token: operator (=)"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (%.a)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/dot_2.js';
+        var command = uglifyjscmd + ' test/input/invalid/dot_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/dot_2.js:1,0",
-               "%.a;",
-               "^",
-               "ERROR: Unexpected token: operator (%)"
-           ].join("\n"));
-           done();
-       });
+        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/dot_2.js:1,0",
+                "%.a;",
+                "^",
+                "ERROR: Unexpected token: operator (%)"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (a./();)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/dot_3.js';
+        var command = uglifyjscmd + ' test/input/invalid/dot_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/dot_3.js:1,2",
-               "a./();",
-               "  ^",
-               "ERROR: Unexpected token: operator (/)"
-           ].join("\n"));
-           done();
-       });
+        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/dot_3.js:1,2",
+                "a./();",
+                "  ^",
+                "ERROR: Unexpected token: operator (/)"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error ({%: 1})", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/object.js';
+        var command = uglifyjscmd + ' test/input/invalid/object.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/object.js:1,13",
-               "console.log({%: 1});",
-               "             ^",
-               "ERROR: Unexpected token: operator (%)"
-           ].join("\n"));
-           done();
-       });
+        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/object.js:1,13",
+                "console.log({%: 1});",
+                "             ^",
+                "ERROR: Unexpected token: operator (%)"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should throw syntax error (delete x)", function(done) {
-       var command = uglifyjscmd + ' test/input/invalid/delete.js';
+        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:13,11",
-               "    delete x;",
-               "           ^",
-               "ERROR: Calling delete on expression not allowed in strict mode"
-           ].join("\n"));
-           done();
-       });
+        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:13,11",
+                "    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';
+        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();
-       });
+        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';
+        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();
-       });
+        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';
+        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();
-       });
+        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';
+        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();
-       });
+        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';
+        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();
-       });
+        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 throw syntax error (else)", function(done) {
+        var command = uglifyjscmd + ' test/input/invalid/else.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/else.js:1,7",
+                "if (0) else 1;",
+                "       ^",
+                "ERROR: Unexpected token: keyword (else)"
+            ].join("\n"));
+            done();
+        });
+    });
+    it("Should throw syntax error (return)", function(done) {
+        var command = uglifyjscmd + ' test/input/invalid/return.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/return.js:1,0",
+                "return 42;",
+                "^",
+                "ERROR: 'return' outside of function"
+            ].join("\n"));
+            done();
+        });
     });
     it("Should handle literal string as source map input", function(done) {
         var command = [