Question

1. Embedded spaces are illegal.
2. A simple_identifier, c_identifier, and arrayed_reference shall start with an alpha or underscore ( _ ) character, shall have at least one character, and shall not have any spaces.
3. The $ character in a system_tf_identifier shall not be followed by white_space. A system_tf_identifier shall not be escaped.
4. End of file.
5. The unsigned number or fixed point number in time_literal shall not be followed by a white_space.
6. implicit_class_handle shall only appear within the scope of a class_declaration or out-of-block method declaration.
7. In any one declaration, only one of protected or local is allowed, only one of rand or randc is allowed, and static and/or virtual can appear only once.
8. dpi_function_proto return types are restricted to small values, as per 27.4.5.
9. Formals of dpi_function_proto and dpi_task_proto cannot use pass by reference mode and class types cannot be passed at all; for the complete set of restrictions see 27.4.6.
10. The apostrophe ( ‘ ) in unbased_unsized_literal shall not be followed by white_space.
11. unsized_dimension is permitted only in declarations of import DPI functions, see dpi_function_proto.
12. More than one unsized dimension is permitted only in declarations of import DPI functions, see dpi_function_proto.
13. When a packed dimension is used with the struct or union keyword, the packed keyword shall also be used.
14. A charge strength shall only be used with the trireg keyword. When the vectored or scalared keyword is used, there shall be at least one packed dimension.
15. In a data_declaration that is not within the procedural context, it shall be illegal to use the automatic keyword.
16. It shall be legal to omit the covergroup_variable_identifer from a covergroup instantiation only if this implicit instantiation is within a class that has no other instantiation of the covergroup.
17. The .* token shall appear at most once in a list of port connections.
18. A timeunits_declaration shall be legal as a non_port_module_item, non_port_interface_item, non_port_program_item, package_item or class_item only if it repeats and matches a previous timeunits_declaration within the same time scope.
19. In a multiple_concatenation, it shall be illegal for the multiplier not to be a constant_expression unless the type of the concatenation is string.
20. In a shallow copy the expression must evaluate to an object handle.
21. It shall be legal to use the $ primary in an open_value_range of the form [ expression : $ ] or [ $ : expression ].
22. { } shall only be legal in the context of a queue.
23. The $ primary shall be legal only in a select for a queue variable or in an open_value_range.
24. A type_identifier shall be legal as an enum_base_type if it denotes an integer_atom_type, with which an additional packed dimension is not permitted, or an integer_vector_type.
25. In a constant_function_call, all arguments shall be constant_expressions.
26. The list_of_port_declarations syntax is explained in Section 18.8, which also imposes various semantic restrictions, e.g., a ref port must be of a variable type and an inout port must not be. It shall be illegal to initialize a port that is not a variable output port.
27. It shall be legal to declare a void struct_union_member only within tagged unions.