Remarks 

The $HINTS directive controls the generation of hint messages by the Delphi compiler. 

In the {$HINTS ON} state, the compiler issues hint messages when detecting unused variables, unused assignments, for or while loops that never execute, and so on. In the {$HINTS OFF} state, the compiler generates no hint messages. 

By placing code between {$HINTS OFF} and {$HINTS ON} directives, you can selectively turn off hints that you don't care about. For example,

{$HINTS OFF}
    procedure Test;
    var
     I: Integer;
    begin
    end;
    {$HINTS ON}

Because of the $HINTS directives the compiler will not generate an unused variable hint when compiling the procedure above.