A value assigned to a variable is never used.

Defect 77722 (STATIC_C)
Checker UNUSED_VALUE (subcategory none)
File: /src/third_party/wiredtiger/src/btree/bt_walk.c
Function __tree_walk_internal
/src/third_party/wiredtiger/src/btree/bt_walk.c, line: 592
Overwriting previous write to "couple" with value from "ref".

    descend:			couple = ref;

/src/third_party/wiredtiger/src/btree/bt_walk.c, line: 353
Assigning value from "couple_orig" to "couple" here, but that stored value is overwritten before it can be used.

    		couple = couple_orig = ref = &btree->root;