relax input params for IndexIVFRaBitQ::get_InvertedListScanner() (facebookresearch#4270)

Summary: Pull Request resolved: facebookresearch#4270

Reviewed By: mnorris11

Differential Revision: D72254929

Pulled By: junjieqi

fbshipit-source-id: 8354b58007d50d1daf06a3bfff4d2d05962c16af

Author: alexanderguzhva

faiss/IndexIVFRaBitQ.cpp

@@ -183,13 +183,9 @@ InvertedListScanner* IndexIVFRaBitQ::get_InvertedListScanner(
         const IDSelector* sel,
         const IVFSearchParameters* search_params_in) const {
     uint8_t used_qb = qb;
-    if (search_params_in != nullptr) {
-        const auto* search_params =
-                dynamic_cast<const IVFRaBitQSearchParameters*>(
-                        search_params_in);
-        FAISS_THROW_IF_NOT_MSG(search_params, "invalid search params");
-
-        used_qb = search_params->qb;
+    if (auto params = dynamic_cast<const IVFRaBitQSearchParameters*>(
+                search_params_in)) {
+        used_qb = params->qb;
     }
 
     return new RaBitInvertedListScanner(*this, store_pairs, sel, used_qb);