Correctly check for duplicate parameter names

Those are not allowed as soon as we have default values for parameters
or rest arguments.

Change-Id: I7dec826c37e6045e4dd1f6b0adb90301efe33daf
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 4 insertions, 2 deletions

diff --git a/src/qml/compiler/qv4compilerscanfunctions.cpp b/src/qml/compiler/qv4compilerscanfunctions.cpp
index f985c74f9d..8824a47def 100644
--- a/src/qml/compiler/qv4compilerscanfunctions.cpp
+++ b/src/qml/compiler/qv4compilerscanfunctions.cpp
@@ -431,12 +431,14 @@ void ScanFunctions::enterFunction(Node *ast, const QString &name, FormalParamete
     if (body && !_context->isStrict)
         checkDirectivePrologue(body->elements);
 
+    bool isSimpleParameterList = formals->isSimpleParameterList();
+
     for (FormalParameterList *it = formals; it; it = it->next) {
         QString arg = it->name.toString();
         int duplicateIndex = _context->arguments.indexOf(arg);
         if (duplicateIndex != -1) {
-            if (_context->isStrict) {
-                _cg->throwSyntaxError(it->identifierToken, QStringLiteral("Duplicate parameter name '%1' is not allowed in strict mode").arg(arg));
+            if (_context->isStrict || !isSimpleParameterList) {
+                _cg->throwSyntaxError(it->identifierToken, QStringLiteral("Duplicate parameter name '%1' is not allowed.").arg(arg));
                 return;
             } else {
                 // change the name of the earlier argument to enforce the specified lookup semantics