The Supreme Court of Pennsylvania held that even if the lower court denies defendants their confrontation right to reveal bias by exposing a witness' pending conviction, the decision will not be reversed if the error was harmless.
Commonwealth v. Lane, 621 A.2d 566 (Pa. 1993).
Christine M. Guthrie,
Constitutional Law - Sixth Amendment - Defendant's Right of Confrontation - Impeachment to Show Bias,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol32/iss2/8