metadata: decoder: remove dead code
metadata: filesearch: remove dead code
middle: astencode: remove dead code
middle: borrowck: remove dead code
middle: cfg: allow dead code
middle: const_eval: remove dead code
middle: dataflow: remove dead code
middle: freevars: remove dead code
middle: graph: ignore dead code
middle: kind: remove dead code
middle: lang_items: allow dead code
middle: mem_categorization: remove dead code
middle: pat_util: remove dead code
middle: region: remove dead code
middle: trans: adt: remove dead code
middle: trans: base: remove dead code
middle: trans: build: remove dead code
middle: trans: builder: ignore dead code
middle: trans: cabi: remove dead code
middle: trans: callee: remove dead code