public void warning(int pos, Warning warningKey) {
        report(diags.warning(null, source, wrap(pos), warningKey));
    }
public void warning ( int pos , Warning warningKey ) { report ( diags . warning ( null , source , wrap ( pos ) , warningKey ) ) ; }
Report a warning, unless suppressed by the  -nowarn option or the
maximum number of warnings has been reached.
@param pos    The source position at which to report the warning.
@param warningKey    The key for the localized warning message.