Prof. Colin Miller tells us that,
When a hearsay statement has been admitted in evidence, the declarant’s credibility may be attacked, and then supported, by any evidence that would be admissible for those purposes if the declarant had testified as a witness. The court may admit evidence of the declarant’s inconsistent statement or conduct, regardless of when it occurred or whether the declarant had an opportunity to explain or deny it. If the party against whom the statement was admitted calls the declarant as a witness, the party may examine the declarant on the statement as if on cross-examination.
In other words, when a declarant’s hearsay statement is admitted pursuant to a hearsay exception or exclusion, the declarant’s credibility can be impeached as if the declarant were a witness at trial.
In Commonwealth v. Williams, 2021 WL 245297 (Pa.Super 2021), Joseph Williams was convicted of two counts of first-degree murder and related crimes in which the issue arose. The appellate court found a harmless error.