QmlJs: sync qmljs parser

The last version of the grammar contains some constructs that the code model
needs to know.

Task-number: QTCREATORBUG-17842
Change-Id: I6250f96431acc05b19f3fd1b6cc268a07485cf0f
Reviewed-by: Leena Miettinen <riitta-leena.miettinen@qt.io>
Reviewed-by: Tim Jenssen <tim.jenssen@qt.io>

src/libs/qmljs/parser/qmldirparser.cpp

@@ -174,6 +174,15 @@ bool QmlDirParser::parse(const QString &source)
 
             _plugins.append(entry);
 
+        } else if (sections[0] == QLatin1String("classname")) {
+            if (sectionCount < 2) {
+                reportError(lineNumber, 0,
+                            QStringLiteral("classname directive requires an argument, but %1 were provided").arg(sectionCount - 1));
+
+                continue;
+            }
+
+            // Ignore these. qmlimportscanner uses them.
         } else if (sections[0] == QLatin1String("internal")) {
             if (sectionCount != 3) {
                 reportError(lineNumber, 0,