extern void *malloc(__SIZE_TYPE__);

enum tree_code {
ERROR_MARK,
IDENTIFIER_NODE,
OP_IDENTIFIER,
TREE_LIST,
TREE_VEC,
BLOCK,
VOID_TYPE,
INTEGER_TYPE,
REAL_TYPE,
COMPLEX_TYPE,
VECTOR_TYPE,
ENUMERAL_TYPE,
BOOLEAN_TYPE,
CHAR_TYPE,
POINTER_TYPE,
OFFSET_TYPE,
REFERENCE_TYPE,
METHOD_TYPE,
FILE_TYPE,
ARRAY_TYPE,
SET_TYPE,
RECORD_TYPE,
UNION_TYPE,
QUAL_UNION_TYPE,
FUNCTION_TYPE,
LANG_TYPE,
INTEGER_CST,
REAL_CST,
COMPLEX_CST,
STRING_CST,
FUNCTION_DECL,
LABEL_DECL,
CONST_DECL,
TYPE_DECL,
VAR_DECL,
PARM_DECL,
RESULT_DECL,
FIELD_DECL,
NAMESPACE_DECL,
COMPONENT_REF,
BIT_FIELD_REF,
INDIRECT_REF,
BUFFER_REF,
ARRAY_REF,
CONSTRUCTOR,
COMPOUND_EXPR,
MODIFY_EXPR,
INIT_EXPR,
TARGET_EXPR,
COND_EXPR,
BIND_EXPR,
CALL_EXPR,
METHOD_CALL_EXPR,
WITH_CLEANUP_EXPR,
CLEANUP_POINT_EXPR,
PLACEHOLDER_EXPR,
WITH_RECORD_EXPR,
PLUS_EXPR,
MINUS_EXPR,
MULT_EXPR,
TRUNC_DIV_EXPR,
CEIL_DIV_EXPR,
FLOOR_DIV_EXPR,
ROUND_DIV_EXPR,
TRUNC_MOD_EXPR,
CEIL_MOD_EXPR,
FLOOR_MOD_EXPR,
ROUND_MOD_EXPR,
RDIV_EXPR,
EXACT_DIV_EXPR,
FIX_TRUNC_EXPR,
FIX_CEIL_EXPR,
FIX_FLOOR_EXPR,
FIX_ROUND_EXPR,
FLOAT_EXPR,
EXPON_EXPR,
NEGATE_EXPR,
MIN_EXPR,
MAX_EXPR,
ABS_EXPR,
FFS_EXPR,
LSHIFT_EXPR,
RSHIFT_EXPR,
LROTATE_EXPR,
RROTATE_EXPR,
BIT_IOR_EXPR,
BIT_XOR_EXPR,
BIT_AND_EXPR,
BIT_ANDTC_EXPR,
BIT_NOT_EXPR,
TRUTH_ANDIF_EXPR,
TRUTH_ORIF_EXPR,
TRUTH_AND_EXPR,
TRUTH_OR_EXPR,
TRUTH_XOR_EXPR,
TRUTH_NOT_EXPR,
LT_EXPR,
LE_EXPR,
GT_EXPR,
GE_EXPR,
EQ_EXPR,
NE_EXPR,
UNORDERED_EXPR,
ORDERED_EXPR,
UNLT_EXPR,
UNLE_EXPR,
UNGT_EXPR,
UNGE_EXPR,
UNEQ_EXPR,
IN_EXPR,
SET_LE_EXPR,
CARD_EXPR,
RANGE_EXPR,
CONVERT_EXPR,
NOP_EXPR,
NON_LVALUE_EXPR,
SAVE_EXPR,
UNSAVE_EXPR,
RTL_EXPR,
ADDR_EXPR,
REFERENCE_EXPR,
ENTRY_VALUE_EXPR,
COMPLEX_EXPR,
CONJ_EXPR,
REALPART_EXPR,
IMAGPART_EXPR,
PREDECREMENT_EXPR,
PREINCREMENT_EXPR,
POSTDECREMENT_EXPR,
POSTINCREMENT_EXPR,
VA_ARG_EXPR,
TRY_CATCH_EXPR,
TRY_FINALLY_EXPR,
GOTO_SUBROUTINE_EXPR,
POPDHC_EXPR,
POPDCC_EXPR,
LABEL_EXPR,
GOTO_EXPR,
RETURN_EXPR,
EXIT_EXPR,
LOOP_EXPR,
LABELED_BLOCK_EXPR,
EXIT_BLOCK_EXPR,
EXPR_WITH_FILE_LOCATION,
SWITCH_EXPR,
  LAST_AND_UNUSED_TREE_CODE
};
typedef union tree_node *tree;
struct tree_common
{
  union tree_node *chain;
  union tree_node *type;
  enum tree_code code : 8;
  unsigned side_effects_flag : 1;
  unsigned constant_flag : 1;
  unsigned permanent_flag : 1;
  unsigned addressable_flag : 1;
  unsigned volatile_flag : 1;
  unsigned readonly_flag : 1;
  unsigned unsigned_flag : 1;
  unsigned asm_written_flag: 1;
  unsigned used_flag : 1;
  unsigned nothrow_flag : 1;
  unsigned static_flag : 1;
  unsigned public_flag : 1;
  unsigned private_flag : 1;
  unsigned protected_flag : 1;
  unsigned bounded_flag : 1;
  unsigned lang_flag_0 : 1;
  unsigned lang_flag_1 : 1;
  unsigned lang_flag_2 : 1;
  unsigned lang_flag_3 : 1;
  unsigned lang_flag_4 : 1;
  unsigned lang_flag_5 : 1;
  unsigned lang_flag_6 : 1;
};
union tree_node
{
  struct tree_common common;
 };
enum c_tree_code {
  C_DUMMY_TREE_CODE = LAST_AND_UNUSED_TREE_CODE,
SRCLOC,
SIZEOF_EXPR,
ARROW_EXPR,
ALIGNOF_EXPR,
EXPR_STMT,
COMPOUND_STMT,
DECL_STMT,
IF_STMT,
FOR_STMT,
WHILE_STMT,
DO_STMT,
RETURN_STMT,
BREAK_STMT,
CONTINUE_STMT,
SWITCH_STMT,
GOTO_STMT,
LABEL_STMT,
ASM_STMT,
SCOPE_STMT,
CASE_LABEL,
STMT_EXPR,
  LAST_C_TREE_CODE
};
enum cplus_tree_code {
  CP_DUMMY_TREE_CODE = LAST_C_TREE_CODE,
OFFSET_REF,
PTRMEM_CST,
NEW_EXPR,
VEC_NEW_EXPR,
DELETE_EXPR,
VEC_DELETE_EXPR,
SCOPE_REF,
MEMBER_REF,
TYPE_EXPR,
AGGR_INIT_EXPR,
THROW_EXPR,
EMPTY_CLASS_EXPR,
TEMPLATE_DECL,
TEMPLATE_PARM_INDEX,
TEMPLATE_TYPE_PARM,
TEMPLATE_TEMPLATE_PARM,
BOUND_TEMPLATE_TEMPLATE_PARM,
TYPENAME_TYPE,
TYPEOF_TYPE,
USING_DECL,
DEFAULT_ARG,
TEMPLATE_ID_EXPR,
CPLUS_BINDING,
OVERLOAD,
WRAPPER,
LOOKUP_EXPR,
FUNCTION_NAME,
MODOP_EXPR,
CAST_EXPR,
REINTERPRET_CAST_EXPR,
CONST_CAST_EXPR,
STATIC_CAST_EXPR,
DYNAMIC_CAST_EXPR,
DOTSTAR_EXPR,
TYPEID_EXPR,
PSEUDO_DTOR_EXPR,
SUBOBJECT,
CTOR_STMT,
CLEANUP_STMT,
START_CATCH_STMT,
CTOR_INITIALIZER,
RETURN_INIT,
TRY_BLOCK,
HANDLER,
TAG_DEFN,
IDENTITY_CONV,
LVALUE_CONV,
QUAL_CONV,
STD_CONV,
PTR_CONV,
PMEM_CONV,
BASE_CONV,
REF_BIND,
USER_CONV,
AMBIG_CONV,
RVALUE_CONV,
  LAST_CPLUS_TREE_CODE
};

blah(){}

convert_like_real (convs)
     tree convs;
{
  switch (((enum tree_code) (convs)->common.code))
    {
    case AMBIG_CONV:
      return blah();
    default:
      break;
    };
   abort ();
}

main()
{
  tree convs = (void *)malloc (sizeof (struct tree_common));;

  convs->common.code = AMBIG_CONV;
  convert_like_real (convs);
  exit (0);
}