@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 
{
    
    WalletBatch batch(*database);
    batch.ErasePool(nIndex);
    WalletLogPrintf("keypool keep %d\n", nIndex);
}
void CWallet::ReturnKey(int64_t nIndex, bool fInternal, const CPubKey& pubkey)
{
    
    {
        LOCK(cs_wallet);
        if (fInternal) {
            setInternalKeyPool.insert(nIndex);
        } else if (!set_pre_split_keypool.empty()) {
            set_pre_split_keypool.insert(nIndex);
        } else {
            setExternalKeyPool.insert(nIndex);
        }
        m_pool_key_to_index[pubkey.GetID()] = nIndex;
        NotifyCanGetAddressesChanged();
    }
    WalletLogPrintf("keypool return %d\n", nIndex);
}
bool CWallet::GetKeyFromPool(CPubKey& result, bool internal)