New Rule: never repeat unary operators about plsql-and-sql-coding-guidelines HOT 3 CLOSED

I ran the following test on my 19c database instance:

set echo on
set serveroutput on
declare
   l_test number;
begin
   l_test := ++1;
   dbms_output.put_line(l_test);
end;
/
select ++1 from dual;

The result was:

SQL> set echo on
SQL> set serveroutput on
SQL> declare
  2     l_test number;
  3  begin
  4     l_test := ++1;
  5     dbms_output.put_line(l_test);
  6  end;
  7  /
1


PL/SQL procedure successfully completed.

SQL> select ++1 from dual;

Error starting at line : 10 in command -
select ++1 from dual
Error at Command Line : 10 Column : 9
Error report -
SQL Error: ORA-00936: missing expression
00936. 00000 -  "missing expression"
*Cause:    
*Action:

Using repeated unary operators seems to be possible for PL/SQL only. In SQL this leads to an error, which I consider good. As long as the PL/SQL parser is not able to detect this kind of errors, an additional rule makes sense.

from plsql-and-sql-coding-guidelines.

@silviomarghitola Is this a SonarSource rule? I could not find it.

from plsql-and-sql-coding-guidelines.

I checked our PL/SQL parser. This:

declare
   l_test number;
begin
   l_test := ++1;
   dbms_output.put_line(l_test);
end;
/

leads to a parse error at line 4, column 16. From my point of view this is correct. In fact I think for this case an Oracle SR should be opened instead of adding a rule and fixing the parser to support "wrong" syntax.

from plsql-and-sql-coding-guidelines.