docs: def p_variable_declaration(self, p):
          """variable_declaration : identifier
                                  | identifier initializer
          """
          if len(p) == 2:
              p[0] = self.asttypes.VarDecl(p[1])
              p[0].setpos(p)  # require yacc_tracking
          else:
              p[0] = self.asttypes.VarDecl(p[1], p[2])
              p[0].setpos(p, additional=(('=', 2),))