Current bitcoin-master on testnet, `maxconnections=8` in the config file. Running in VM that doesn't have public IP and is not reachable from the Internet.

Wait until you have 8 peers.

```
telnet localhost 18333
```

It will result in:

```
Assertion failed: (nMaxInbound > 0), function AcceptConnection, file net.cpp, line 973.
```

First found in https://github.com/bitcoin/bitcoin/pull/8996, but can be reproduced on master.

{
    boost::mutex condition_mutex;
    boost::unique_lock<boost::mutex> lock(condition_mutex);
    while (true)
    {
        std::vector<CNode*> vNodesCopy;
        {
            LOCK(cs_vNodes);
            vNodesCopy = vNodes;
            BOOST_FOREACH(CNode* pnode, vNodesCopy) {
                pnode->AddRef();
            }
        }
        bool fSleep = true;
        BOOST_FOREACH(CNode* pnode, vNodesCopy)
        {
            if (pnode->fDisconnect)
                continue;
            
            {
                TRY_LOCK(pnode->cs_vRecvMsg, lockRecv);
                if (lockRecv)
                {