macro expansion is not correct

[the-die]

chibicc -E macro.c

will get

BAR() 1

however

gcc -E macro.c

will get

BAR_I ()() 1 1 1

// macro.c
#define EMPTY()
#define DEFER(id) id EMPTY()
#define EXPAND(...) __VA_ARGS__
#define BAR_I() BAR
#define BAR()  DEFER(BAR_I)()() 1
EXPAND(EXPAND(BAR()))

[fuhsnn]

This fork has it fixed: https://github.com/n0tknowing/chibicc

Or checkout my fork's alternative algorithm fuhsnn/slimcc@c3a1194