Freed internal location read

Reading from freed memory can cause wrong values to be read and crashes due to illegal memory accesses. Reads target of a freed internal pointer
/src/mongo/db/matcher/implicit_validator.cpp:80: WRAPPER_ESCAPE 121905 Calling "back" which extracts wrapped state from "level->subobjs".
/src/mongo/db/matcher/implicit_validator.cpp:80: WRAPPER_ESCAPE 121905 Assigning: "level" = "level->subobjs.back()".
/src/mongo/db/matcher/implicit_validator.cpp:78: WRAPPER_ESCAPE 121905 Calling "push_back" invalidates the internal representation of "level->subobjs".
/src/mongo/db/matcher/implicit_validator.cpp:80: WRAPPER_ESCAPE 121905 Using invalidated internal representation of "level->subobjs".