1 struct tree_decl
2 {
3   unsigned in_system_header_flag:1;
4 };
5 union tree_node
6 {
7   struct tree_decl decl;
8 };
9 typedef union tree_node *tree;
10 static int
redeclaration_error_message(olddecl)11 redeclaration_error_message (olddecl)
12      tree olddecl;
13 {
14   if (({olddecl;})->decl.in_system_header_flag)
15     ;
16 }
17