3 files changed, 9 insertions, 6 deletions
diff --git a/src/tools/moc/collectjson.cpp b/src/tools/moc/collectjson.cpp
index ed65a9ed08..6577a3216b 100644
--- a/src/tools/moc/collectjson.cpp
+++ b/src/tools/moc/collectjson.cpp
@@ -51,7 +51,7 @@ static bool readFromDevice(QIODevice *device, QJsonArray *allMetaObjects)
     return true;
 }
 
-int collectJson(const QStringList &jsonFiles, const QString &outputFile)
+int collectJson(const QStringList &jsonFiles, const QString &outputFile, bool skipStdIn)
 {
     QHashSeed::setDeterministicGlobalSeed();
 
@@ -70,7 +70,7 @@ int collectJson(const QStringList &jsonFiles, const QString &outputFile)
     }
 
     QJsonArray allMetaObjects;
-    if (jsonFiles.isEmpty()) {
+    if (jsonFiles.isEmpty() && !skipStdIn) {
         QFile f;
         if (!f.open(stdin, QIODevice::ReadOnly)) {
             fprintf(stderr, "Error opening stdin for reading\n");
diff --git a/src/tools/moc/collectjson.h b/src/tools/moc/collectjson.h
index 9d329c96ca..3a33952a54 100644
--- a/src/tools/moc/collectjson.h
+++ b/src/tools/moc/collectjson.h
@@ -35,7 +35,7 @@
 
 QT_BEGIN_NAMESPACE
 
-int collectJson(const QStringList &jsonFiles, const QString &outputFile);
+int collectJson(const QStringList &jsonFiles, const QString &outputFile, bool skipStdIn);
 
 QT_END_NAMESPACE
 
diff --git a/src/tools/moc/main.cpp b/src/tools/moc/main.cpp
index 1cb383c92f..a2790fa1f7 100644
--- a/src/tools/moc/main.cpp
+++ b/src/tools/moc/main.cpp
@@ -145,9 +145,10 @@ QByteArray composePreprocessorOutput(const Symbols &symbols) {
     return output;
 }
 
-static QStringList argumentsFromCommandLineAndFile(const QStringList &arguments)
+static QStringList argumentsFromCommandLineAndFile(const QStringList &arguments, bool &hasOptionFiles)
 {
     QStringList allArguments;
+    hasOptionFiles = false;
     allArguments.reserve(arguments.size());
     for (const QString &argument : arguments) {
         // "@file" doesn't start with a '-' so we can't use QCommandLineParser for it
@@ -163,6 +164,7 @@ static QStringList argumentsFromCommandLineAndFile(const QStringList &arguments)
                 error("Cannot open options file specified with @");
                 return QStringList();
             }
+            hasOptionFiles = true;
             while (!f.atEnd()) {
                 QString line = QString::fromLocal8Bit(f.readLine().trimmed());
                 if (!line.isEmpty())
@@ -378,7 +380,8 @@ int runMoc(int argc, char **argv)
     parser.addPositionalArgument(QStringLiteral("[MOC generated json file]"),
                                  QStringLiteral("MOC generated json output"));
 
-    const QStringList arguments = argumentsFromCommandLineAndFile(app.arguments());
+    bool hasOptionFiles = false;
+    const QStringList arguments = argumentsFromCommandLineAndFile(app.arguments(), hasOptionFiles);
     if (arguments.isEmpty())
         return 1;
 
@@ -387,7 +390,7 @@ int runMoc(int argc, char **argv)
     const QStringList files = parser.positionalArguments();
     output = parser.value(outputOption);
     if (parser.isSet(collectOption))
-        return collectJson(files, output);
+        return collectJson(files, output, hasOptionFiles);
 
     if (files.count() > 1) {
         error(qPrintable(QLatin1String("Too many input files specified: '") + files.join(QLatin1String("' '")) + QLatin1Char('\'')));