anchor.diff:    | seq_block
     | wait_statement
     | procedural_assertion_statement
  -  | clocking_drive SEMI
  +  | clocking_drive_statement
     | randsequence_statement
     | randcase_statement
     | expect_property_statement
  
positive.code:   | HASH LPAREN mintypmax_expression RPAREN
    ;
  
  clocking_drive
    : clockvar_expression LT_EQ cycle_delay? expression
    ;
  
  clockvar
  
negative.code:   ;
  
  statement_expression
    : expression LT_EQ delay_or_event_control expression  // non-blocking assignment
    | expression EQ delay_or_event_control expression      // blocking assignment
    | expression EQ dynamic_array_new                      // dynamic array init
    | expression EQ class_new                              // object init
  