For a typedef "using Foo=QList<int>", shiboken generates SBK_QLIST_INT besides SBK_FOO which is then matched by function arguments. The code was however missing a check to restrict this to typedefs, so it triggered for class Alternative : public QVariantList, class Sequence : public QVariantList producing duplicate indexes. Restrict this to real typedefs (which are also represented as classes. Split out the function creating the special alternate index for clarity and add a check for potential equivalent typedefs which would also produce clashes. Pick-to: 6.1 Task-number: PYSIDE-1571 Change-Id: I9275963c4ddb8fc589e414ee1fa19282f6004793 Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>