NOP_EXPR is used as a special case (see truthvalue_conversion). */
extern void binary_op_error (location_t, enum tree_code, tree, tree);
extern tree fix_string_type (tree);
-struct varray_head_tag;
extern void constant_expression_warning (tree);
extern void constant_expression_error (tree);
extern bool strict_aliasing_warning (tree, tree, tree);