[INFO] crate monad 0.0.2 is already in cache
[INFO] extracting crate monad 0.0.2 into work/ex/beta-1.38-1/sources/1.37.0/reg/monad/0.0.2
[INFO] extracting crate monad 0.0.2 into work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/monad/0.0.2
[INFO] validating manifest of monad-0.0.2 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 monad-0.0.2 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 monad-0.0.2
[INFO] removed path dependency monad_macros from monad-0.0.2
[INFO] finished frobbing monad-0.0.2
[INFO] frobbed toml for monad-0.0.2 written to work/ex/beta-1.38-1/sources/1.37.0/reg/monad/0.0.2/Cargo.toml
[INFO] started frobbing monad-0.0.2
[INFO] removed path dependency monad_macros from monad-0.0.2
[INFO] finished frobbing monad-0.0.2
[INFO] frobbed toml for monad-0.0.2 written to work/ex/beta-1.38-1/sources/beta-2019-08-13/reg/monad/0.0.2/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 monad-0.0.2 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-2/1.37.0:/opt/crater/target:rw,Z" "-v" "/mnt/big/crater/work/ex/beta-1.38-1/sources/1.37.0/reg/monad/0.0.2:/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] 52c71c0bec3974c9c2bf8de3dcaa9d28a927c7bd368bc0615d382c3e40f87cc1
[INFO] running `"docker" "start" "-a" "52c71c0bec3974c9c2bf8de3dcaa9d28a927c7bd368bc0615d382c3e40f87cc1"`
[INFO] [stderr]    Compiling free_macros v0.0.1
[INFO] [stderr]    Compiling tailrec v0.0.4
[INFO] [stderr]    Compiling monad_macros v0.0.1
[INFO] [stderr] error: macros that expand to items must be delimited with braces or followed by a semicolon
[INFO] [stderr]    --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/free_macros-0.0.1/src/free/monad.rs:2:19
[INFO] [stderr]     |
[INFO] [stderr] 2   |   macro_rules! monad(
[INFO] [stderr]     |  ___________________^
[INFO] [stderr] 3   | |     ($M:ident, $Sig:ident, $sig_map:ident, [ $($ctx:ident,)* ]) =>
[INFO] [stderr] 4   | |     {
[INFO] [stderr] 5   | |
[INFO] [stderr] ...   |
[INFO] [stderr] 256 | |     };
[INFO] [stderr] 257 | | )
[INFO] [stderr]     | |_^
[INFO] [stderr] help: change the delimiters to curly braces
[INFO] [stderr]     |
[INFO] [stderr] 2   | macro_rules! monad {
[INFO] [stderr] 3   |     ($M:ident, $Sig:ident, $sig_map:ident, [ $($ctx:ident,)* ]) =>
[INFO] [stderr] 4   |     {
[INFO] [stderr] 5   | 
[INFO] [stderr] 6   |         #[allow(dead_code)]
[INFO] [stderr] 7   |         struct Opaque(*const u8);
[INFO] [stderr]   ...
[INFO] [stderr] help: add a semicolon
[INFO] [stderr]     |
[INFO] [stderr] 257 | );
[INFO] [stderr]     |  ^
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: non-builtin inner attributes are unstable
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/free_macros-0.0.1/src/lib.rs:4:1
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![license = "MIT"]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: for more information, see https://github.com/rust-lang/rust/issues/54726
[INFO] [stderr] 
[INFO] [stderr] error[E0658]: The attribute `license` is currently unknown to the compiler and may have meaning added to it in the future
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/free_macros-0.0.1/src/lib.rs:4:4
[INFO] [stderr]   |
[INFO] [stderr] 4 | #![license = "MIT"]
[INFO] [stderr]   |    ^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: for more information, see https://github.com/rust-lang/rust/issues/29642
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/free_macros-0.0.1/src/lib.rs:7:1
[INFO] [stderr]   |
[INFO] [stderr] 7 | #![feature(macro_rules)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/free_macros-0.0.1/src/lib.rs:8:1
[INFO] [stderr]   |
[INFO] [stderr] 8 | #![feature(unboxed_closures)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 5 previous errors
[INFO] [stderr] 
[INFO] [stderr] Some errors have detailed explanations: E0554, E0658.
[INFO] [stderr] For more information about an error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `free_macros`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: `$p:pat` is followed by `:`, which is not allowed for `pat` fragments
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/monad_macros-0.0.1/src/lib.rs:16:17
[INFO] [stderr]    |
[INFO] [stderr] 16 |         $p: pat : $ty: ty <- $e: expr ; $( $t: tt )*
[INFO] [stderr]    |                 ^ not allowed after `pat` fragments
[INFO] [stderr]    |
[INFO] [stderr]    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
[INFO] [stderr] 
[INFO] [stderr] error: `$ty:ty` is followed by `<-`, which is not allowed for `ty` fragments
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/monad_macros-0.0.1/src/lib.rs:16:27
[INFO] [stderr]    |
[INFO] [stderr] 16 |         $p: pat : $ty: ty <- $e: expr ; $( $t: tt )*
[INFO] [stderr]    |                           ^^ not allowed after `ty` fragments
[INFO] [stderr]    |
[INFO] [stderr]    = note: allowed there are: `{`, `[`, `=>`, `,`, `>`, `=`, `:`, `;`, `|`, `as` or `where`
[INFO] [stderr] 
[INFO] [stderr] error: `$p:pat` is followed by `<-`, which is not allowed for `pat` fragments
[INFO] [stderr]   --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/monad_macros-0.0.1/src/lib.rs:21:17
[INFO] [stderr]    |
[INFO] [stderr] 21 |         $p: pat <- $e: expr ; $( $t: tt )*
[INFO] [stderr]    |                 ^^ not allowed after `pat` fragments
[INFO] [stderr]    |
[INFO] [stderr]    = note: allowed there are: `=>`, `,`, `=`, `|`, `if` or `in`
[INFO] [stderr] 
[INFO] [stderr] error[E0554]: #![feature] may not be used on the stable release channel
[INFO] [stderr]  --> /opt/crater/cargo-home/registry/src/github.com-1ecc6299db9ec823/monad_macros-0.0.1/src/lib.rs:1:1
[INFO] [stderr]   |
[INFO] [stderr] 1 | #![feature(macro_rules)]
[INFO] [stderr]   | ^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] error: aborting due to 4 previous errors
[INFO] [stderr] 
[INFO] [stderr] For more information about this error, try `rustc --explain E0554`.
[INFO] [stderr] error: Could not compile `monad_macros`.
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] [stderr] error: build failed
[INFO] running `"docker" "inspect" "52c71c0bec3974c9c2bf8de3dcaa9d28a927c7bd368bc0615d382c3e40f87cc1"`
[INFO] running `"docker" "rm" "-f" "52c71c0bec3974c9c2bf8de3dcaa9d28a927c7bd368bc0615d382c3e40f87cc1"`
[INFO] [stdout] 52c71c0bec3974c9c2bf8de3dcaa9d28a927c7bd368bc0615d382c3e40f87cc1