Using master. During startup, if you open `Window` -> `Console` and try and execute any command (can be garbage) `bitcoin-qt` will crash:
```bash
On branch pull/16118/local-merge

Process 89287 launched: '/Users/michael/github/bitcoin/src/qt/bitcoin-qt' (x86_64)
2019-05-29 09:57:56.276746-0400 bitcoin-qt[89287:939924] MessageTracer: Falling back to default whitelist
Process 89287 stopped
* thread #1, name = 'bitcoin-main', queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x8)
    frame #0: 0x00000001015158ba QtWidgets`QCompleter::popup() const + 10
QtWidgets`QCompleter::popup:
->  0x1015158ba <+10>: movq   0x8(%rdi), %rbx
    0x1015158be <+14>: movq   0x88(%rbx), %rax
    0x1015158c5 <+21>: testq  %rax, %rax
    0x1015158c8 <+24>: jne    0x101515942               ; <+146>
Target 0: (bitcoin-qt) stopped.
```

Not sure if just disabling the menu, like in #16118 would be ok, as a user might actually want to be able to run a command.
if (!--nDepthInsideSensitive) {
                assert(filter_begin_pos);
                filter_ranges.push_back(std::make_pair(filter_begin_pos, chpos));
                filter_begin_pos = 0;
            }
        }
        stack.pop_back();
    };
    std::string strCommandTerminated = strCommand;
    if (strCommandTerminated.back() != '\n')
        strCommandTerminated += "\n";
    for (chpos = 0; chpos < strCommandTerminated.size(); ++chpos)
    {
        char ch = strCommandTerminated[chpos];
        switch(state)
        {
            case STATE_COMMAND_EXECUTED_INNER:
            case STATE_COMMAND_EXECUTED:
            {
                bool breakParsing = true;
                switch(ch)
                {
                    case '[': curarg.clear(); state = STATE_COMMAND_EXECUTED_INNER; break;
                    default:
                        if (state == STATE_COMMAND_EXECUTED_INNER)
                        {
                            if (ch != ']')
                            {
                                
                                curarg += ch;