Dereference of an explicit null value

Defect 99991 (STATIC_C)
Checker FORWARD_NULL (subcategory deref_constant_null)
File: /src/mongoc/mongoc-topology-description.c
Function mongoc_topology_description_handle_ismaster
/src/mongoc/mongoc-topology-description.c, line: 1638
Assigning: "prev_sd" = "NULL".

       mongoc_server_description_t *prev_sd = NULL;