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.
{
        STATE_EATING_SPACES,
        STATE_EATING_SPACES_IN_ARG,
        STATE_EATING_SPACES_IN_BRACKETS,
        STATE_ARGUMENT,
        STATE_SINGLEQUOTED,
        STATE_DOUBLEQUOTED,
        STATE_ESCAPE_OUTER,
        STATE_ESCAPE_DOUBLEQUOTED,
        STATE_COMMAND_EXECUTED,
        STATE_COMMAND_EXECUTED_INNER
    } state = STATE_EATING_SPACES;
    std::string curarg;
    UniValue lastResult;
    unsigned nDepthInsideSensitive = 0;
    size_t filter_begin_pos = 0, chpos;
    std::vector<std::pair<size_t, size_t>> filter_ranges;
    auto add_to_current_stack = [&](const std::string& strArg) {
        if (stack.back().empty() && (!nDepthInsideSensitive) && historyFilter.contains(QString::fromStdString(strArg), Qt::CaseInsensitive)) {
            nDepthInsideSensitive = 1;
            filter_begin_pos = chpos;
        }
        
        if (stack.empty()) {
            stack.push_back(std::vector<std::string>());
        }
        stack.back().push_back(strArg);
    };
    auto close_out_params = [&]() {
        if (nDepthInsideSensitive) {