[INFO] fetching crate rwt 0.4.0...
[INFO] checking rwt-0.4.0 against master#ceab6128fa48a616bfd3e3adf4bc80133b8ee223 for no-never-type-fallback
[INFO] extracting crate rwt 0.4.0 into /workspace/builds/worker-1-tc1/source
[INFO] validating manifest of crates.io crate rwt 0.4.0 on toolchain ceab6128fa48a616bfd3e3adf4bc80133b8ee223
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rwt 0.4.0
[INFO] finished tweaking crates.io crate rwt 0.4.0
[INFO] tweaked toml for crates.io crate rwt 0.4.0 written to /workspace/builds/worker-1-tc1/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] [stderr]      Locking 26 packages
[INFO] [stderr]       Adding base64 v0.12.3 (latest: v0.22.0)
[INFO] [stderr]       Adding rand v0.3.23 (latest: v0.8.5)
[INFO] [stderr]       Adding rand v0.4.6 (latest: v0.8.5)
[INFO] [stderr]       Adding rand_core v0.3.1 (latest: v0.6.4)
[INFO] [stderr]       Adding rand_core v0.4.2 (latest: v0.6.4)
[INFO] [stderr]       Adding rdrand v0.4.0 (latest: v0.8.3)
[INFO] [stderr]       Adding time v0.1.45 (latest: v0.3.34)
[INFO] [stderr]       Adding wasi v0.10.0+wasi-snapshot-preview1 (latest: v0.13.0+wasi-0.2.0)
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 5217f976aec0c24c13b90ee9042bf8681a5fd5f08ff8e423e87608588d047788
[INFO] running `Command { std: "docker" "start" "-a" "5217f976aec0c24c13b90ee9042bf8681a5fd5f08ff8e423e87608588d047788", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "5217f976aec0c24c13b90ee9042bf8681a5fd5f08ff8e423e87608588d047788", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "5217f976aec0c24c13b90ee9042bf8681a5fd5f08ff8e423e87608588d047788", kill_on_drop: false }`
[INFO] [stdout] 5217f976aec0c24c13b90ee9042bf8681a5fd5f08ff8e423e87608588d047788
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc1/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+ceab6128fa48a616bfd3e3adf4bc80133b8ee223" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 9690d2b8cb77d409ebddca06d282ca6023482d3d9d6e9d37475ee179906a7840
[INFO] running `Command { std: "docker" "start" "-a" "9690d2b8cb77d409ebddca06d282ca6023482d3d9d6e9d37475ee179906a7840", kill_on_drop: false }`
[INFO] [stderr]    Compiling gcc v0.3.55
[INFO] [stderr]     Checking base64 v0.12.3
[INFO] [stderr]     Checking rand v0.3.23
[INFO] [stderr]     Checking serde v1.0.197
[INFO] [stderr]    Compiling rust-crypto v0.2.36
[INFO] [stderr]     Checking serde_json v1.0.115
[INFO] [stderr]     Checking rwt v0.4.0 (/opt/rustwide/workdir)
[INFO] [stdout] warning: the item `serde_json` is imported redundantly
[INFO] [stdout]    --> src/lib.rs:126:9
[INFO] [stdout]     |
[INFO] [stdout] 126 |     use serde_json;
[INFO] [stdout]     |         ^^^^^^^^^^ the item `serde_json` is already defined by prelude
[INFO] [stdout]     |
[INFO] [stdout]     = note: `#[warn(unused_imports)]` on by default
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] warning: 1 warning emitted
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stderr]     Finished `dev` profile [unoptimized + debuginfo] target(s) in 1.95s
[INFO] running `Command { std: "docker" "inspect" "9690d2b8cb77d409ebddca06d282ca6023482d3d9d6e9d37475ee179906a7840", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "9690d2b8cb77d409ebddca06d282ca6023482d3d9d6e9d37475ee179906a7840", kill_on_drop: false }`
[INFO] [stdout] 9690d2b8cb77d409ebddca06d282ca6023482d3d9d6e9d37475ee179906a7840
[INFO] checking rwt-0.4.0 against try#3a4bc97f6385a3aa300a4fd689b44350e54fd676 for no-never-type-fallback
[INFO] extracting crate rwt 0.4.0 into /workspace/builds/worker-1-tc2/source
[INFO] validating manifest of crates.io crate rwt 0.4.0 on toolchain 3a4bc97f6385a3aa300a4fd689b44350e54fd676
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }`
[INFO] started tweaking crates.io crate rwt 0.4.0
[INFO] finished tweaking crates.io crate rwt 0.4.0
[INFO] tweaked toml for crates.io crate rwt 0.4.0 written to /workspace/builds/worker-1-tc2/source/Cargo.toml
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "generate-lockfile" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] [stderr]     Updating crates.io index
[INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }`
[INFO] [stdout] 53acd3aa89e9dac00304449e43cc22a6e8009c77b76f04b3d444118124e4f980
[INFO] running `Command { std: "docker" "start" "-a" "53acd3aa89e9dac00304449e43cc22a6e8009c77b76f04b3d444118124e4f980", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "inspect" "53acd3aa89e9dac00304449e43cc22a6e8009c77b76f04b3d444118124e4f980", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "53acd3aa89e9dac00304449e43cc22a6e8009c77b76f04b3d444118124e4f980", kill_on_drop: false }`
[INFO] [stdout] 53acd3aa89e9dac00304449e43cc22a6e8009c77b76f04b3d444118124e4f980
[INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-1-tc2/source:/opt/rustwide/workdir:ro,Z" "-v" "/var/lib/crater-agent-workspace/cargo-home:/opt/rustwide/cargo-home:ro,Z" "-v" "/var/lib/crater-agent-workspace/rustup-home:/opt/rustwide/rustup-home:ro,Z" "-e" "SOURCE_DIR=/opt/rustwide/workdir" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "RUSTDOCFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--user" "0:0" "--network" "none" "ghcr.io/rust-lang/crates-build-env/linux@sha256:2788e3201cd34a07e3172128adcd8b3090168a8e3bcc40d7c032b9dda1df7d1c" "/opt/rustwide/cargo-home/bin/cargo" "+3a4bc97f6385a3aa300a4fd689b44350e54fd676" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }`
[INFO] [stdout] 127e669e95df059add53f7f36afa2c90256398f6a09186e01b4a6edac6d2e6ed
[INFO] running `Command { std: "docker" "start" "-a" "127e669e95df059add53f7f36afa2c90256398f6a09186e01b4a6edac6d2e6ed", kill_on_drop: false }`
[INFO] [stderr]    Compiling gcc v0.3.55
[INFO] [stderr]    Compiling serde_json v1.0.115
[INFO] [stderr]     Checking rustc-serialize v0.3.25
[INFO] [stderr]     Checking ryu v1.0.17
[INFO] [stderr]     Checking base64 v0.12.3
[INFO] [stderr]     Checking rand v0.3.23
[INFO] [stderr]     Checking serde v1.0.197
[INFO] [stderr]    Compiling rust-crypto v0.2.36
[INFO] [stdout] error[E0282]: type annotations needed
[INFO] [stdout]     --> /opt/rustwide/cargo-home/registry/src/index.crates.io-6f17d22bba15001f/rustc-serialize-0.3.25/src/json.rs:1387:20
[INFO] [stdout]      |
[INFO] [stdout] 1387 |             _ => { panic!(); }
[INFO] [stdout]      |                    ^^^^^^^^ cannot infer type
[INFO] [stdout]      |
[INFO] [stdout]      = note: this error originates in the macro `$crate::panic::panic_2015` which comes from the expansion of the macro `panic` (in Nightly builds, run with -Z macro-backtrace for more info)
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] error: aborting due to 1 previous error
[INFO] [stdout] 
[INFO] [stdout] 
[INFO] [stdout] For more information about this error, try `rustc --explain E0282`.
[INFO] [stdout] 
[INFO] [stderr] error: could not compile `rustc-serialize` (lib) due to 2 previous errors
[INFO] [stderr] warning: build failed, waiting for other jobs to finish...
[INFO] running `Command { std: "docker" "inspect" "127e669e95df059add53f7f36afa2c90256398f6a09186e01b4a6edac6d2e6ed", kill_on_drop: false }`
[INFO] running `Command { std: "docker" "rm" "-f" "127e669e95df059add53f7f36afa2c90256398f6a09186e01b4a6edac6d2e6ed", kill_on_drop: false }`
[INFO] [stdout] 127e669e95df059add53f7f36afa2c90256398f6a09186e01b4a6edac6d2e6ed