@jonasschnelli wrote in #14979:
> #14573 broke < Qt5.6 compatibility due to calling the lambda version of `addAction` that was added in Qt5.6.

We currently [support](https://github.com/bitcoin/bitcoin/blob/master/doc/dependencies.md) QT >=5.2, but hardly anyone tests with that. If we make one of the Travis machines use it, we should have a better change of catching this.

See also discussion about minimum QT version in #13478 
for (std::set<CTxDestination> _grouping : groupings)
    {
        
        std::set< std::set<CTxDestination>* > hits;
        std::map< CTxDestination, std::set<CTxDestination>* >::iterator it;
        for (const CTxDestination& address : _grouping)
            if ((it = setmap.find(address)) != setmap.end())
                hits.insert((*it).second);
        
        std::set<CTxDestination>* merged = new std::set<CTxDestination>(_grouping);
        for (std::set<CTxDestination>* hit : hits)
        {
            merged->insert(hit->begin(), hit->end());
            uniqueGroupings.erase(hit);
            delete hit;
        }
        uniqueGroupings.insert(merged);
        
        for (const CTxDestination& element : *merged)
            setmap[element] = merged;
    }
    std::set< std::set<CTxDestination> > ret;
    for (const std::set<CTxDestination>* uniqueGrouping : uniqueGroupings)
    {
        ret.insert(*uniqueGrouping);
        delete uniqueGrouping;
    }
    return ret;
}
std::set<CTxDestination> CWallet::GetLabelAddresses(const std::string& label) const