Cryptic malloc crash

[Jackmill]

I have a basic QAction set up as a sort of test action:

actions_.network_ping_ = new QAction(tr("Ping"), this);
	connect(actions_.network_ping_, &QAction::triggered,
		this, [this] {
			osc_service_->send(EosOscMessage::ping());
		});

Whenever I trigger this action, it works as expected, and does exactly as prescribed, but then my program crashes with an error that I don't know what to do with:

PaletteRepo(74405,0x16d1ab000) malloc: Corruption of free object 0x14402bb90: msizes 25903/0 disagree
PaletteRepo(74405,0x16d1ab000) malloc: *** set a breakpoint in malloc_error_break to debug

This still happens if I rewrite that lambda in the connect call into a slot.

If I set a breakpoint and step through, it takes me to qobjectdefs_impl.h, specifically line 116:

template <typename, typename, typename, typename> struct FunctorCall;
    template <size_t... II, typename... SignalArgs, typename R, typename Function>
struct FunctorCall<std::index_sequence<II...>, List<SignalArgs...>, R, Function> : FunctorCallBase
    {
        static void call(Function &f, void **arg)
        {
            call_internal<R>(arg, [&] {
                return f((*reinterpret_cast<typename RemoveRef<SignalArgs>::Type *>(arg[II+1]))...); // < This line
            });
        }
    };

I'm not super familiar with malloc so I don't know what malloc_error_break is or how to set a breakpoint there as the error suggests.

Does anybody have any guidance here?

This is in CLion on macOS Sequoia.

[Pl45m4]

@Jackmill

What type is actions_.network_ping?
And does it also crash when you remove the 3rd Party function from your lambda/slot?

[JonB]

@Jackmill
As @Pl45m4 has written.
Do you mean it crashes after the connect() call, or do you mean it crashes after the first time the signal is actually emitted and the slot/lambda is called?
Make the body of the slot/lambda just do a qDebug() << "Hello world"; and not call anything else.