The Infer industrial static analyser performs highly scalable interprocedural analysis thanks to compositional reasoning. This means that each procedure is given a summary, which is computed without knowledge of the possible call sites invariants in the whole program. Summary Specialization is a new technique we have recently introduced in Infer. It relaxes the obligation to not make no assumptions about call sites, but avoids imaginating too many useless call scenario, nor switching to a full-fledged global analysis. We will introduce this new technique and report on some experimental evalution we have done on the specific topic of closure resolution.