Qt Creator treats packagesExist incorrectly

Qt Creator mistakenly thinks that a packagesExist in a .pro file is true, when in fact it's not.

For example, append the following to a .pro file:

packagesExist(this_is_not_gonna_be_installed) {
    DEFINES += SHOULD_NOT_BE_DEFINED
    message("hello world")
    TARGET = aaa_bbb_ccc
}

In this case, if you #ifdef for SHOULD_NOT_BE_DEFINED you can see that it's not defined (correct) however Qt Creator will still try to launch the executable "aaa_bbb_ccc" and tell the following:

Executable /home/Timur/Projects/misc/build-untitled1-Fedora_Qt5-Debug/aaa_bbb_ccc does not exist.