[INFO] cloning repository https://github.com/przprz/rust-on-lambda [INFO] running `Command { std: "git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "clone" "--bare" "https://github.com/przprz/rust-on-lambda" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Frust-on-lambda", kill_on_drop: false }` [INFO] [stderr] Cloning into bare repository '/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Frust-on-lambda'... [INFO] running `Command { std: "git" "rev-parse" "HEAD", kill_on_drop: false }` [INFO] [stdout] 9cc50126f164f32128f9d033a38903f167456d85 [INFO] checking przprz/rust-on-lambda against master#385fa9d845dd326c6bbfd58c22244215e431948a for never-type-fallback-to-never [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Frust-on-lambda" "/workspace/builds/worker-2-tc1/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc1/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/przprz/rust-on-lambda on toolchain 385fa9d845dd326c6bbfd58c22244215e431948a [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] removed /workspace/builds/worker-2-tc1/source/.cargo/config [INFO] started tweaking git repo https://github.com/przprz/rust-on-lambda [INFO] finished tweaking git repo https://github.com/przprz/rust-on-lambda [INFO] tweaked toml for git repo https://github.com/przprz/rust-on-lambda written to /workspace/builds/worker-2-tc1/source/Cargo.toml [INFO] crate git repo https://github.com/przprz/rust-on-lambda already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+385fa9d845dd326c6bbfd58c22244215e431948a" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] [stderr] Updating crates.io index [INFO] [stderr] Downloading crates ... [INFO] [stderr] Downloaded iana-time-zone v0.1.45 [INFO] [stderr] Downloaded lambda_runtime_client v0.1.0 [INFO] [stderr] Downloaded lambda_runtime v0.1.0 [INFO] [stderr] Downloaded time v0.3.13 [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 4d2c2000c82338eb27217caa153267b6d77d4aedef9b218c04ba6a258deed32f [INFO] running `Command { std: "docker" "start" "-a" "4d2c2000c82338eb27217caa153267b6d77d4aedef9b218c04ba6a258deed32f", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "4d2c2000c82338eb27217caa153267b6d77d4aedef9b218c04ba6a258deed32f", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "4d2c2000c82338eb27217caa153267b6d77d4aedef9b218c04ba6a258deed32f", kill_on_drop: false }` [INFO] [stdout] 4d2c2000c82338eb27217caa153267b6d77d4aedef9b218c04ba6a258deed32f [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc1/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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" "+385fa9d845dd326c6bbfd58c22244215e431948a" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }` [INFO] [stdout] db588c521ac237f3fccd6d2dd539912e835389b1dc704363535b3c2e0a76f562 [INFO] running `Command { std: "docker" "start" "-a" "db588c521ac237f3fccd6d2dd539912e835389b1dc704363535b3c2e0a76f562", kill_on_drop: false }` [INFO] [stderr] Compiling libc v0.2.132 [INFO] [stderr] Compiling log v0.4.17 [INFO] [stderr] Compiling crossbeam-utils v0.7.2 [INFO] [stderr] Compiling maybe-uninit v2.0.0 [INFO] [stderr] Checking byteorder v1.4.3 [INFO] [stderr] Checking either v1.8.0 [INFO] [stderr] Compiling slab v0.4.7 [INFO] [stderr] Compiling memoffset v0.5.6 [INFO] [stderr] Compiling proc-macro2 v1.0.43 [INFO] [stderr] Compiling crossbeam-epoch v0.8.2 [INFO] [stderr] Compiling quote v1.0.21 [INFO] [stderr] Compiling unicode-ident v1.0.3 [INFO] [stderr] Compiling syn v1.0.99 [INFO] [stderr] Checking lock_api v0.3.4 [INFO] [stderr] Checking tokio-sync v0.1.8 [INFO] [stderr] Compiling parking_lot_core v0.6.2 [INFO] [stderr] Compiling parking_lot v0.9.0 [INFO] [stderr] Compiling memchr v2.5.0 [INFO] [stderr] Compiling indexmap v1.9.1 [INFO] [stderr] Compiling cc v1.0.73 [INFO] [stderr] Compiling serde v1.0.143 [INFO] [stderr] Compiling num-traits v0.2.15 [INFO] [stderr] Checking tinyvec_macros v0.1.0 [INFO] [stderr] Checking itoa v1.0.3 [INFO] [stderr] Checking smallvec v0.6.14 [INFO] [stderr] Checking gimli v0.26.2 [INFO] [stderr] Compiling httparse v1.7.1 [INFO] [stderr] Checking hashbrown v0.12.3 [INFO] [stderr] Checking miniz_oxide v0.5.3 [INFO] [stderr] Checking tinyvec v1.6.0 [INFO] [stderr] Compiling hyper v0.12.36 [INFO] [stderr] Compiling num-integer v0.1.45 [INFO] [stderr] Checking rustc-demangle v0.1.21 [INFO] [stderr] Compiling serde_derive v1.0.143 [INFO] [stderr] Compiling serde_json v1.0.83 [INFO] [stderr] Checking object v0.29.0 [INFO] [stderr] Checking tokio-executor v0.1.10 [INFO] [stderr] Checking crossbeam-queue v0.2.3 [INFO] [stderr] Checking want v0.2.0 [INFO] [stderr] Checking tokio-timer v0.2.13 [INFO] [stderr] Checking tokio-current-thread v0.1.7 [INFO] [stderr] Checking iovec v0.1.4 [INFO] [stderr] Checking num_cpus v1.13.1 [INFO] [stderr] Checking net2 v0.2.37 [INFO] [stderr] Checking time v0.1.44 [INFO] [stderr] Checking bytes v0.4.12 [INFO] [stderr] Checking crossbeam-deque v0.7.4 [INFO] [stderr] Checking futures-cpupool v0.1.8 [INFO] [stderr] Checking mio v0.6.23 [INFO] [stderr] Checking unicode-normalization v0.1.21 [INFO] [stderr] Checking atty v0.2.14 [INFO] [stderr] Checking tokio-threadpool v0.1.18 [INFO] [stderr] Checking ryu v1.0.11 [INFO] [stderr] Compiling unicode-xid v0.2.3 [INFO] [stderr] Compiling failure_derive v0.1.8 [INFO] [stderr] Compiling time-macros v0.2.4 [INFO] [stderr] Checking unicode-bidi v0.3.8 [INFO] [stderr] Checking colored v1.9.3 [INFO] [stderr] Checking tokio-io v0.1.13 [INFO] [stderr] Checking http v0.1.21 [INFO] [stderr] Checking tokio-buf v0.1.1 [INFO] [stderr] Checking string v0.2.1 [INFO] [stderr] Checking iana-time-zone v0.1.45 [INFO] [stderr] Compiling backtrace v0.3.66 [INFO] [stderr] Checking percent-encoding v1.0.1 [INFO] [stderr] Checking dtoa v0.4.8 [INFO] [stderr] Checking base64 v0.10.1 [INFO] [stderr] Checking idna v0.1.5 [INFO] [stderr] Checking mio-uds v0.6.8 [INFO] [stderr] Checking tokio-reactor v0.1.12 [INFO] [stderr] Checking tokio-codec v0.1.2 [INFO] [stderr] Checking tokio-fs v0.1.7 [INFO] [stderr] Checking tokio-tcp v0.1.4 [INFO] [stderr] Checking tokio-uds v0.2.7 [INFO] [stderr] Checking tokio-udp v0.1.6 [INFO] [stderr] Checking url v1.7.2 [INFO] [stderr] Checking chrono v0.4.22 [INFO] [stderr] Checking tokio v0.1.22 [INFO] [stderr] Checking addr2line v0.17.0 [INFO] [stderr] Checking time v0.3.13 [INFO] [stderr] Checking http-body v0.1.0 [INFO] [stderr] Checking h2 v0.1.26 [INFO] [stderr] Checking simple_logger v1.16.0 [INFO] [stderr] Checking serde_urlencoded v0.5.5 [INFO] [stderr] Compiling synstructure v0.12.6 [INFO] [stderr] Checking failure v0.1.8 [INFO] [stderr] Checking lambda_runtime_client v0.1.0 [INFO] [stderr] Checking lambda_runtime v0.1.0 [INFO] [stderr] Checking bootstrap v0.1.0 (/opt/rustwide/workdir) [INFO] [stderr] Finished `dev` profile [unoptimized + debuginfo] target(s) in 8.57s [INFO] running `Command { std: "docker" "inspect" "db588c521ac237f3fccd6d2dd539912e835389b1dc704363535b3c2e0a76f562", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "db588c521ac237f3fccd6d2dd539912e835389b1dc704363535b3c2e0a76f562", kill_on_drop: false }` [INFO] [stdout] db588c521ac237f3fccd6d2dd539912e835389b1dc704363535b3c2e0a76f562 [INFO] checking przprz/rust-on-lambda against try#2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 for never-type-fallback-to-never [INFO] running `Command { std: "git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2Fprzprz%2Frust-on-lambda" "/workspace/builds/worker-2-tc2/source", kill_on_drop: false }` [INFO] [stderr] Cloning into '/workspace/builds/worker-2-tc2/source'... [INFO] [stderr] done. [INFO] validating manifest of git repo https://github.com/przprz/rust-on-lambda on toolchain 2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2 [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--manifest-path" "Cargo.toml" "--no-deps", kill_on_drop: false }` [INFO] removed /workspace/builds/worker-2-tc2/source/.cargo/config [INFO] started tweaking git repo https://github.com/przprz/rust-on-lambda [INFO] finished tweaking git repo https://github.com/przprz/rust-on-lambda [INFO] tweaked toml for git repo https://github.com/przprz/rust-on-lambda written to /workspace/builds/worker-2-tc2/source/Cargo.toml [INFO] crate git repo https://github.com/przprz/rust-on-lambda already has a lockfile, it will not be regenerated [INFO] running `Command { std: CARGO_HOME="/workspace/cargo-home" RUSTUP_HOME="/workspace/rustup-home" "/workspace/cargo-home/bin/cargo" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "fetch" "--manifest-path" "Cargo.toml", kill_on_drop: false }` [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "metadata" "--no-deps" "--format-version=1", kill_on_drop: false }` [INFO] [stdout] 0b103dc1809e6c7726b3d7f8ee996a1ac7f5a932ea48f4bc3949aa2e97b8b6b1 [INFO] running `Command { std: "docker" "start" "-a" "0b103dc1809e6c7726b3d7f8ee996a1ac7f5a932ea48f4bc3949aa2e97b8b6b1", kill_on_drop: false }` [INFO] running `Command { std: "docker" "inspect" "0b103dc1809e6c7726b3d7f8ee996a1ac7f5a932ea48f4bc3949aa2e97b8b6b1", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "0b103dc1809e6c7726b3d7f8ee996a1ac7f5a932ea48f4bc3949aa2e97b8b6b1", kill_on_drop: false }` [INFO] [stdout] 0b103dc1809e6c7726b3d7f8ee996a1ac7f5a932ea48f4bc3949aa2e97b8b6b1 [INFO] running `Command { std: "docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-tc2/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-2-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" "+2d84f2737f3bd9ebfcb07f75aa198d6cf7c715d2" "check" "--frozen" "--all" "--all-targets" "--message-format=json", kill_on_drop: false }` [INFO] [stdout] 82f21cffe6088b616ec594ea420687ecb9959dcf1ec02de1c901f8910c687cdc [INFO] running `Command { std: "docker" "start" "-a" "82f21cffe6088b616ec594ea420687ecb9959dcf1ec02de1c901f8910c687cdc", kill_on_drop: false }` [INFO] [stderr] Compiling libc v0.2.132 [INFO] [stderr] Compiling log v0.4.17 [INFO] [stderr] Compiling crossbeam-utils v0.7.2 [INFO] [stderr] Checking byteorder v1.4.3 [INFO] [stderr] Compiling maybe-uninit v2.0.0 [INFO] [stderr] Checking either v1.8.0 [INFO] [stderr] Compiling slab v0.4.7 [INFO] [stderr] Compiling memoffset v0.5.6 [INFO] [stderr] Compiling proc-macro2 v1.0.43 [INFO] [stderr] Checking lock_api v0.3.4 [INFO] [stderr] Compiling crossbeam-epoch v0.8.2 [INFO] [stderr] Compiling quote v1.0.21 [INFO] [stderr] Compiling unicode-ident v1.0.3 [INFO] [stderr] Checking tokio-sync v0.1.8 [INFO] [stderr] Compiling syn v1.0.99 [INFO] [stderr] Compiling parking_lot_core v0.6.2 [INFO] [stderr] Compiling parking_lot v0.9.0 [INFO] [stderr] Compiling memchr v2.5.0 [INFO] [stderr] Compiling indexmap v1.9.1 [INFO] [stderr] Compiling cc v1.0.73 [INFO] [stderr] Compiling serde v1.0.143 [INFO] [stderr] Compiling num-traits v0.2.15 [INFO] [stderr] Checking tinyvec_macros v0.1.0 [INFO] [stderr] Checking gimli v0.26.2 [INFO] [stderr] Compiling httparse v1.7.1 [INFO] [stderr] Checking hashbrown v0.12.3 [INFO] [stderr] Checking itoa v1.0.3 [INFO] [stderr] Checking miniz_oxide v0.5.3 [INFO] [stderr] Checking tinyvec v1.6.0 [INFO] [stderr] Checking smallvec v0.6.14 [INFO] [stderr] Compiling hyper v0.12.36 [INFO] [stderr] Compiling num-integer v0.1.45 [INFO] [stderr] Compiling serde_derive v1.0.143 [INFO] [stderr] Compiling serde_json v1.0.83 [INFO] [stderr] Checking rustc-demangle v0.1.21 [INFO] [stderr] Checking tokio-executor v0.1.10 [INFO] [stderr] Checking crossbeam-queue v0.2.3 [INFO] [stderr] Checking object v0.29.0 [INFO] [stderr] Checking tokio-current-thread v0.1.7 [INFO] [stderr] Checking iovec v0.1.4 [INFO] [stderr] Checking num_cpus v1.13.1 [INFO] [stderr] Checking net2 v0.2.37 [INFO] [stderr] Checking bytes v0.4.12 [INFO] [stderr] Checking time v0.1.44 [INFO] [stderr] Checking tokio-timer v0.2.13 [INFO] [stderr] Checking crossbeam-deque v0.7.4 [INFO] [stderr] Checking unicode-normalization v0.1.21 [INFO] [stderr] Checking mio v0.6.23 [INFO] [stderr] Checking tokio-threadpool v0.1.18 [INFO] [stderr] Checking futures-cpupool v0.1.8 [INFO] [stderr] Checking tokio-io v0.1.13 [INFO] [stderr] Checking http v0.1.21 [INFO] [stderr] Checking string v0.2.1 [INFO] [stderr] Checking tokio-buf v0.1.1 [INFO] [stderr] Checking atty v0.2.14 [INFO] [stderr] Checking want v0.2.0 [INFO] [stderr] Compiling failure_derive v0.1.8 [INFO] [stderr] Compiling unicode-xid v0.2.3 [INFO] [stderr] Compiling time-macros v0.2.4 [INFO] [stderr] Checking ryu v1.0.11 [INFO] [stderr] Checking unicode-bidi v0.3.8 [INFO] [stderr] Checking colored v1.9.3 [INFO] [stderr] Compiling backtrace v0.3.66 [INFO] [stderr] Checking iana-time-zone v0.1.45 [INFO] [stderr] Checking tokio-codec v0.1.2 [INFO] [stderr] Checking tokio-fs v0.1.7 [INFO] [stderr] Checking percent-encoding v1.0.1 [INFO] [stderr] Checking dtoa v0.4.8 [INFO] [stderr] Checking tokio-reactor v0.1.12 [INFO] [stderr] Checking mio-uds v0.6.8 [INFO] [stderr] Checking base64 v0.10.1 [INFO] [stderr] Checking idna v0.1.5 [INFO] [stderr] Checking chrono v0.4.22 [INFO] [stderr] Checking tokio-uds v0.2.7 [INFO] [stderr] Checking tokio-tcp v0.1.4 [INFO] [stderr] Checking tokio-udp v0.1.6 [INFO] [stderr] Checking tokio v0.1.22 [INFO] [stderr] Checking url v1.7.2 [INFO] [stderr] Checking addr2line v0.17.0 [INFO] [stderr] Checking time v0.3.13 [INFO] [stderr] Checking http-body v0.1.0 [INFO] [stderr] Checking h2 v0.1.26 [INFO] [stderr] Checking simple_logger v1.16.0 [INFO] [stderr] Checking serde_urlencoded v0.5.5 [INFO] [stderr] Compiling synstructure v0.12.6 [INFO] [stderr] Checking failure v0.1.8 [INFO] [stderr] Checking lambda_runtime_client v0.1.0 [INFO] [stderr] Checking lambda_runtime v0.1.0 [INFO] [stderr] Checking bootstrap v0.1.0 (/opt/rustwide/workdir) [INFO] [stderr] Finished `dev` profile [unoptimized + debuginfo] target(s) in 8.23s [INFO] running `Command { std: "docker" "inspect" "82f21cffe6088b616ec594ea420687ecb9959dcf1ec02de1c901f8910c687cdc", kill_on_drop: false }` [INFO] running `Command { std: "docker" "rm" "-f" "82f21cffe6088b616ec594ea420687ecb9959dcf1ec02de1c901f8910c687cdc", kill_on_drop: false }` [INFO] [stdout] 82f21cffe6088b616ec594ea420687ecb9959dcf1ec02de1c901f8910c687cdc