cargo +c2rust run -- select target 'crate; desc(union);' \; ionize  -- old.rs -L /Users/emertens/Source/rust-epdtry/rust/build/x86_64-apple-darwin/stage2/lib/rustlib/x86_64-apple-darwin/lib

file:///Users/emertens/Source/rust-epdtry/rust/build/x86_64-apple-darwin/doc/rustc/hir/struct.Path.html