shiboken6: Implement opaque containers for getters (non-const)

Extract helpers from the opaque containers generation for fields
and use them for function returns if the type is modified  accordingly.

[ChangeLog][shiboken6] Getters returning containers by reference can
now be modified to return an opaque container by modifying the return
type accordingly.

Pick-to: 6.2
Task-number: PYSIDE-1605
Change-Id: Ieaf5eb92d248d3a23e511222e5f61823e85540c0
Reviewed-by: Christian Tismer <tismer@stackless.com>
Reviewed-by: Cristian Maureira-Fredes <cristian.maureira-fredes@qt.io>

2 files changed, 6 insertions, 0 deletions

diff --git a/sources/shiboken6/tests/libminimal/listuser.cpp b/sources/shiboken6/tests/libminimal/listuser.cpp
index 402696acd..5ad570faa 100644
--- a/sources/shiboken6/tests/libminimal/listuser.cpp
+++ b/sources/shiboken6/tests/libminimal/listuser.cpp
@@ -123,3 +123,8 @@ void ListUser::setStdIntList(const std::list<int> &l)
 {
     m_stdIntList = l;
 }
+
+std::list<int> &ListUser::getIntList()
+{
+    return m_stdIntList;
+}
diff --git a/sources/shiboken6/tests/libminimal/listuser.h b/sources/shiboken6/tests/libminimal/listuser.h
index 31c4efbd1..e3b38049c 100644
--- a/sources/shiboken6/tests/libminimal/listuser.h
+++ b/sources/shiboken6/tests/libminimal/listuser.h
@@ -71,6 +71,7 @@ struct LIBMINIMAL_API ListUser
     int callSumListOfIntLists(std::list<std::list<int> > intListList) { return sumListOfIntLists(intListList); }
 
     void setStdIntList(const std::list<int> &l);
+    std::list<int> &getIntList();
 
     std::list<int> m_stdIntList;
 };