Argument cannot be negative

The negative argument will be interpreted as a very large unsigned value. Negative value used as argument to a function expecting a positive value (for example, size of buffer or allocation)
/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_radix_store.h:2271: REVERSE_NEGATIVE 116119 Passing "context->size() - 2UL" to a parameter that cannot be negative. [Note: The source code implementation of the function has been overridden by a builtin model.]
/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_radix_store.h:2290: REVERSE_NEGATIVE 116119 Assigning: "prevIdx" = "context->size() - 2UL"; now neither can be negative.
/src/mongo/db/storage/ephemeral_for_test/ephemeral_for_test_radix_store.h:2292: REVERSE_NEGATIVE 116119 You might be using variable "prevIdx" before verifying that it is >= 0.