test/Preprocessor/macro_fn_disable_expand.c

// RUN: clang %s -E | grep 'bar foo (2)' &&
// RUN: clang %s -E | grep 'm(ABCD)'

#define foo(x) bar x
foo(foo) (2)


#define m(a) a(w)
#define w ABCD
m(m)   // m(ABCD)