[sherincall]

If you are targeting both C and C++, you do want to cast. If it's just C, the advice is not to cast because a) no point in repeating yourself, and b) it could mask an error if malloc was not declared.

a) is hardly an issue in a one-off macro definition, and b) is hardly an issue as you probably have #include <stdlib.h> just above the define. Besides, sane CFLAGS and any remotely modern compiler will protect you from b) anyway.

There is a minor benefit to casting in this case, as it will error out if I do:

    int *x = new(x, 10); // should be new(int, 10)

because x is not a type.

However, I still think this is terrible advice because it turns something very standard that every beginner C programmer understands into something that requires familiarity with the codebase and incurs a constant cognitive load. It also makes for some very hard to debug errors if I use "new" as a variable name somewhere. Not to mention total incompatibility with C++ due to choice of name.