1 // RUN: %clang_cc1 %s -E | grep 'pre: 1 1 X'
2 // RUN: %clang_cc1 %s -E | grep 'nopre: 1A(X)'
3 
4 /* Preexpansion of argument. */
5 #define A(X) 1 X
6 pre: A(A(X))
7 
8 /* The ## operator disables preexpansion. */
9 #undef A
10 #define A(X) 1 ## X
11 nopre: A(A(X))
12 
13