fix corner case when parsing expression (#4435)

lib/parse.js

@@ -737,7 +737,7 @@ function parse($TEXT, options) {
 
     function semicolon(optional) {
         if (is("punc", ";")) next();
-        else if (!optional && !can_insert_semicolon()) expect_token("punc", ";");
+        else if (!optional && !can_insert_semicolon()) expect(";");
     }
 
     function parenthesised() {
@@ -1166,7 +1166,7 @@ function parse($TEXT, options) {
         expect("{");
         var a = [];
         while (!is("punc", "}")) {
-            if (is("eof")) expect_token("punc", "}");
+            if (is("eof")) expect("}");
             a.push(statement());
         }
         next();
@@ -1177,7 +1177,7 @@ function parse($TEXT, options) {
         expect("{");
         var a = [], branch, cur, default_branch, tmp;
         while (!is("punc", "}")) {
-            if (is("eof")) expect_token("punc", "}");
+            if (is("eof")) expect("}");
             if (is("keyword", "case")) {
                 if (branch) branch.end = prev();
                 cur = [];
@@ -1561,9 +1561,8 @@ function parse($TEXT, options) {
     }
 
     function as_name() {
-        if (!is("name")) expect_token("name");
         var name = S.token.value;
-        next();
+        expect_token("name");
         return name;
     }
 
@@ -1861,7 +1860,9 @@ function parse($TEXT, options) {
 
     if (options.expression) {
         handle_regexp();
-        return expression();
+        var exp = expression();
+        expect_token("eof");
+        return exp;
     }
 
     return function() {

test/mocha/number-literal.js

@@ -89,4 +89,13 @@ describe("Number literals", function() {
             }, code);
         });
     });
+    it("Should reject invalid syntax under expression=true", function() {
+        assert.throws(function() {
+            UglifyJS.parse("42.g", {
+                expression: true,
+            });
+        }, function(e) {
+            return e instanceof UglifyJS.JS_Parse_Error;
+        });
+    });
 });