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.

{
    vstats.clear();
    LOCK(cs_vNodes);
    vstats.reserve(vNodes.size());
    for(std::vector<CNode*>::iterator it = vNodes.begin(); it != vNodes.end(); ++it) {
        CNode* pnode = *it;
        CNodeStats stats;
        pnode->copyStats(stats);
        vstats.push_back(stats);
    }
}
bool CConnman::DisconnectAddress(const CNetAddr& netAddr)
{
    if (CNode* pnode = FindNode(netAddr)) {
        pnode->fDisconnect = true;
        return true;
    }
    return false;
}
bool CConnman::DisconnectSubnet(const CSubNet& subNet)