That is not "never used" as the programmer argues, and I find it misleading that the title of the blogpost tries to sell it as "a never used function is getting

That is not "never used" as the programmer argues, and I find it misleading that the title of the blogpost tries to sell it as "a never used function is getting called". The NeverCalled function has external visibility so it could be eventually called by another CU, and it definitely references (or takes the address of) the supposedly unused "EraseAll" function. In order to be a legal program, some other CU has to call the NeverCalled at some point before main(), and the compiler is just assuming that.