Uninitialized scalar field
The field will contain an arbitrary value left over from earlier computations. A scalar field is not initialized by the constructor
/src/mongo/db/query/query_solution.h:482: UNINIT_CTOR 122081 Class member declaration for "hasCompatibleCollation".
/src/mongo/db/query/query_solution.cpp:308: UNINIT_CTOR 122081 Non-static class member "hasCompatibleCollation" is not initialized in this constructor nor in any functions that it calls.