While checking #16661 I stumbled upon what seems to be a lifetime issue in `ReleaseWallet(CWallet* wallet)` (`wallet.cpp`).

https://github.com/bitcoin/bitcoin/blob/fa6431055abfacea4f72ef11d061c7c755de327a/src/wallet/wallet.cpp#L107-L111

After `delete wallet;` the pointer is invalid and shouldn't be used like in the call `g_unloading_wallet_set.erase(wallet)`.

The code was introduced in #14941 which was merged into `master` on January 15, 2019.

In addition to fixing this specific instance it might be worth thinking about how we can use static analysis to automatically catch this class of issues going forward :-)
{
                keyFail = true;
                break;
            }
            keyPass = true;
            if (fDecryptionThoroughlyChecked)
                break;
        }
        if (keyPass && keyFail)
        {
            LogPrintf("The wallet is probably corrupted: Some keys decrypt but not all.\n");
            throw std::runtime_error("Error unlocking wallet: some keys decrypt but not all. Your wallet file may be corrupt.");
        }
        if (keyFail || (!keyPass && !accept_no_keys))
            return false;
        vMasterKey = vMasterKeyIn;
        fDecryptionThoroughlyChecked = true;
    }
    NotifyStatusChanged(this);
    return true;
}
bool CWallet::HaveKey(const CKeyID &address) const
{
    LOCK(cs_KeyStore);
    if (!IsCrypted()) {
        return FillableSigningProvider::HaveKey(address);
    }
    return mapCryptedKeys.count(address) > 0;
}
bool CWallet::GetKey(const CKeyID &address, CKey& keyOut) const