[INFO] crate hashcons 0.1.1 is already in cache
[INFO] extracting crate hashcons 0.1.1 into work/ex/beta-1.38-1/sources/1.37.0/reg/hashcons/0.1.1
[INFO] extracting crate hashcons 0.1.1 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/hashcons/0.1.1
[INFO] validating manifest of hashcons-0.1.1 on toolchain 1.37.0
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] validating manifest of hashcons-0.1.1 on toolchain beta-2019-08-13
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started frobbing hashcons-0.1.1
[INFO] finished frobbing hashcons-0.1.1
[INFO] frobbed toml for hashcons-0.1.1 written to work/ex/beta-1.38-1/sources/1.37.0/reg/hashcons/0.1.1/Cargo.toml
[INFO] started frobbing hashcons-0.1.1
[INFO] finished frobbing hashcons-0.1.1
[INFO] frobbed toml for hashcons-0.1.1 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/hashcons/0.1.1/Cargo.toml
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "generate-lockfile" "--manifest-path" "Cargo.toml" "-Zno-index-update"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+1.37.0" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"/mnt/big/crater/work/local/cargo-home/bin/cargo" "+beta-2019-08-13" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] testing hashcons-0.1.1 against 1.37.0 for beta-1.38-1
[INFO] running `"docker" "create" "-v" "/mnt/big/crater/work/local/target-dirs/beta-1.38-1/worker-3/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/hashcons/0.1.1:/opt/crater/workdir:ro,Z" "-v" "/mnt/big/crater/work/local/cargo-home:/opt/crater/cargo-home:ro,Z" "-v" "/mnt/big/crater/work/local/rustup-home:/opt/crater/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/opt/crater/workdir" "-e" "MAP_USER_ID=1000" "-e" "CARGO_TARGET_DIR=/opt/crater/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=warn" "-e" "CARGO_HOME=/opt/crater/cargo-home" "-e" "RUSTUP_HOME=/opt/crater/rustup-home" "-w" "/opt/crater/workdir" "-m" "1536M" "--network" "none" "rustops/crates-build-env" "/opt/crater/cargo-home/bin/cargo" "+1.37.0" "build" "--frozen"`
[INFO] [stdout] 75da0aac6b5ba9fe6f79a01cb2f00c7ea40570acfa3927163649b8b0507d8ecb
[INFO] running `"docker" "start" "-a" "75da0aac6b5ba9fe6f79a01cb2f00c7ea40570acfa3927163649b8b0507d8ecb"`
[INFO] [stderr]    Compiling hashcons v0.1.1 (/opt/crater/workdir)
[INFO] [stderr] warning: unused doc comment
[INFO] [stderr]    --> src/merkle.rs:180:1
[INFO] [stderr]     |
[INFO] [stderr] 180 | / /// Global table of serialized objects; permits us to avoid multiple
[INFO] [stderr] 181 | | /// serialized copies of a single, shared object.
[INFO] [stderr]     | |_________________________________________________^
[INFO] [stderr] 182 | / thread_local!(static TABLE:
[INFO] [stderr] 183 | |               RefCell<Table> =
[INFO] [stderr] 184 | |               RefCell::new(Table{
[INFO] [stderr] 185 | |                   copy_count:0,
[INFO] [stderr] 186 | |                   table:HashMap::new()
[INFO] [stderr] 187 | |               }));
[INFO] [stderr]     | |__________________- rustdoc does not generate documentation for macro expansions
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(unused_doc_comments)] on by default
[INFO] [stderr]     = help: to document an item produced by a macro, the macro must produce the documentation as part of its expansion
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(rc_downcast)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/merkle.rs:177:29
[INFO] [stderr]     |
[INFO] [stderr] 177 |     table:HashMap<Id,Box<Rc<Any>>>
[INFO] [stderr]     |                             ^^^ help: use `dyn`: `dyn Any`
[INFO] [stderr]     |
[INFO] [stderr]     = note: #[warn(bare_trait_objects)] on by default
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/merkle.rs:213:29
[INFO] [stderr]     |
[INFO] [stderr] 213 |                 let x : &Rc<Any> = &**brc;
[INFO] [stderr]     |                             ^^^ help: use `dyn`: `dyn Any`
[INFO] [stderr] 
[INFO] [stderr] warning: trait objects without an explicit `dyn` are deprecated
[INFO] [stderr]    --> src/merkle.rs:214:42
[INFO] [stderr]     |
[INFO] [stderr] 214 |                 let y : Result<Rc<T>, Rc<Any>> = (x.clone()).downcast::<T>();
[INFO] [stderr]     |                                          ^^^ help: use `dyn`: `dyn Any`
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to previous error
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `hashcons`.
[INFO] [stderr] 
[INFO] [stderr] To learn more, run the command again with --verbose.
[INFO] running `"docker" "inspect" "75da0aac6b5ba9fe6f79a01cb2f00c7ea40570acfa3927163649b8b0507d8ecb"`
[INFO] running `"docker" "rm" "-f" "75da0aac6b5ba9fe6f79a01cb2f00c7ea40570acfa3927163649b8b0507d8ecb"`
[INFO] [stdout] 75da0aac6b5ba9fe6f79a01cb2f00c7ea40570acfa3927163649b8b0507d8ecb