QObject::connect not recognizing signals

After defining some signals and slots in header files, I attempted to connect the signal to a slot, but the compiler kept giving a warning that the signal does not exist. The warning disappeared after I switched from the MSVC compiler to MinGW.

In both cases, the code builds. In the case with the warning, though, there is no connection between the functions, which I tracked by debugging and stepping into functions. With MinGW, the code works as intended.