[INFO] updating cached repository https://github.com/Lin-H/chip8
[INFO] running `"git" "-c" "credential.helper=" "-c" "credential.helper=/workspace/cargo-home/bin/git-credential-null" "-c" "remote.origin.fetch=refs/heads/*:refs/heads/*" "fetch" "origin" "--force" "--prune"`
[INFO] running `"git" "rev-parse" "HEAD"`
[INFO] [stdout] af437ccf102cddceccfe7d06e20926c3581de988
[INFO] testing Lin-H/chip8 against try#41997647ba6a77908f6ef64401414feb00bccf16 for pr-71274
[INFO] running `"git" "clone" "/workspace/cache/git-repos/https%3A%2F%2Fgithub.com%2FLin-H%2Fchip8" "/workspace/builds/worker-14/source"`
[INFO] [stderr] Cloning into '/workspace/builds/worker-14/source'...
[INFO] [stderr] done.
[INFO] validating manifest of git repo https://github.com/Lin-H/chip8 on toolchain 41997647ba6a77908f6ef64401414feb00bccf16
[INFO] running `"/workspace/cargo-home/bin/cargo" "+41997647ba6a77908f6ef64401414feb00bccf16" "read-manifest" "--manifest-path" "Cargo.toml"`
[INFO] started tweaking git repo https://github.com/Lin-H/chip8
[INFO] finished tweaking git repo https://github.com/Lin-H/chip8
[INFO] tweaked toml for git repo https://github.com/Lin-H/chip8 written to /workspace/builds/worker-14/source/Cargo.toml
[INFO] crate git repo https://github.com/Lin-H/chip8 already has a lockfile, it will not be regenerated
[INFO] running `"/workspace/cargo-home/bin/cargo" "+41997647ba6a77908f6ef64401414feb00bccf16" "fetch" "--locked" "--manifest-path" "Cargo.toml"`
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+41997647ba6a77908f6ef64401414feb00bccf16" "build" "--frozen"`
[INFO] [stdout] 7351398b5877360ade82ea914c7605194b5e92f5fc7cc32928009d4070a74d19
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] running `"docker" "start" "-a" "7351398b5877360ade82ea914c7605194b5e92f5fc7cc32928009d4070a74d19"`
[INFO] [stderr]    Compiling autocfg v0.1.6
[INFO] [stderr]    Compiling rand_core v0.4.2
[INFO] [stderr]    Compiling sdl2 v0.32.2
[INFO] [stderr]    Compiling sdl2-sys v0.32.6
[INFO] [stderr]    Compiling rand_core v0.3.1
[INFO] [stderr]    Compiling rand_os v0.1.3
[INFO] [stderr]    Compiling rand_jitter v0.1.4
[INFO] [stderr]    Compiling rand_xorshift v0.1.1
[INFO] [stderr]    Compiling rand_isaac v0.1.1
[INFO] [stderr]    Compiling rand_hc v0.1.0
[INFO] [stderr]    Compiling num-traits v0.2.8
[INFO] [stderr]    Compiling num-integer v0.1.41
[INFO] [stderr]    Compiling rand_chacha v0.1.1
[INFO] [stderr]    Compiling num-iter v0.1.39
[INFO] [stderr]    Compiling rand_pcg v0.1.2
[INFO] [stderr]    Compiling rand v0.6.5
[INFO] [stderr]    Compiling num v0.1.42
[INFO] [stderr]    Compiling chip8 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `chip8`
[INFO] [stderr]   --> src/main.rs:14:9
[INFO] [stderr]    |
[INFO] [stderr] 14 |     let chip8 = CPU::new(Memory::new());
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chip8`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `op`
[INFO] [stderr]   --> src/cpu.rs:23:13
[INFO] [stderr]    |
[INFO] [stderr] 23 |         let op = self.getOP();
[INFO] [stderr]    |             ^^ help: if this is intentional, prefix it with an underscore: `_op`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `speed`
[INFO] [stderr]  --> src/cpu.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     speed: u16, // 500Hz
[INFO] [stderr]   |     ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `V`
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `I`
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `memory`
[INFO] [stderr]  --> src/cpu.rs:8:5
[INFO] [stderr]   |
[INFO] [stderr] 8 |     memory: Memory,
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `pointer`
[INFO] [stderr]  --> src/cpu.rs:9:5
[INFO] [stderr]   |
[INFO] [stderr] 9 |     pointer: usize
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `run`
[INFO] [stderr]   --> src/cpu.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     pub fn run(&mut self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `getOP`
[INFO] [stderr]   --> src/cpu.rs:26:5
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `set`
[INFO] [stderr]   --> src/memory.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn set(&mut self, data: [u8; 3216]) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `V` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `v`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `I` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `i`
[INFO] [stderr] 
[INFO] [stderr] warning: method `getOP` should have a snake case name
[INFO] [stderr]   --> src/cpu.rs:26:8
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |        ^^^^^ help: convert the identifier to snake case: `get_op`
[INFO] [stderr] 
[INFO] [stderr] warning: 13 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished dev [unoptimized + debuginfo] target(s) in 21.57s
[INFO] running `"docker" "inspect" "7351398b5877360ade82ea914c7605194b5e92f5fc7cc32928009d4070a74d19"`
[INFO] running `"docker" "rm" "-f" "7351398b5877360ade82ea914c7605194b5e92f5fc7cc32928009d4070a74d19"`
[INFO] [stdout] 7351398b5877360ade82ea914c7605194b5e92f5fc7cc32928009d4070a74d19
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+41997647ba6a77908f6ef64401414feb00bccf16" "test" "--frozen" "--no-run"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 54d254f01c0c11e083a335069971f3bef58b624287e680cc8dd2520423f57cb6
[INFO] running `"docker" "start" "-a" "54d254f01c0c11e083a335069971f3bef58b624287e680cc8dd2520423f57cb6"`
[INFO] [stderr]    Compiling chip8 v0.1.0 (/opt/rustwide/workdir)
[INFO] [stderr] warning: unused variable: `chip8`
[INFO] [stderr]   --> src/main.rs:14:9
[INFO] [stderr]    |
[INFO] [stderr] 14 |     let chip8 = CPU::new(Memory::new());
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chip8`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `op`
[INFO] [stderr]   --> src/cpu.rs:23:13
[INFO] [stderr]    |
[INFO] [stderr] 23 |         let op = self.getOP();
[INFO] [stderr]    |             ^^ help: if this is intentional, prefix it with an underscore: `_op`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `speed`
[INFO] [stderr]  --> src/cpu.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     speed: u16, // 500Hz
[INFO] [stderr]   |     ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `V`
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `I`
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `memory`
[INFO] [stderr]  --> src/cpu.rs:8:5
[INFO] [stderr]   |
[INFO] [stderr] 8 |     memory: Memory,
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `pointer`
[INFO] [stderr]  --> src/cpu.rs:9:5
[INFO] [stderr]   |
[INFO] [stderr] 9 |     pointer: usize
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `run`
[INFO] [stderr]   --> src/cpu.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     pub fn run(&mut self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `getOP`
[INFO] [stderr]   --> src/cpu.rs:26:5
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `set`
[INFO] [stderr]   --> src/memory.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn set(&mut self, data: [u8; 3216]) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `V` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `v`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `I` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `i`
[INFO] [stderr] 
[INFO] [stderr] warning: method `getOP` should have a snake case name
[INFO] [stderr]   --> src/cpu.rs:26:8
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |        ^^^^^ help: convert the identifier to snake case: `get_op`
[INFO] [stderr] 
[INFO] [stderr] warning: 13 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 1.17s
[INFO] running `"docker" "inspect" "54d254f01c0c11e083a335069971f3bef58b624287e680cc8dd2520423f57cb6"`
[INFO] running `"docker" "rm" "-f" "54d254f01c0c11e083a335069971f3bef58b624287e680cc8dd2520423f57cb6"`
[INFO] [stdout] 54d254f01c0c11e083a335069971f3bef58b624287e680cc8dd2520423f57cb6
[INFO] running `"docker" "create" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/target:/opt/rustwide/target:rw,Z" "-v" "/var/lib/crater-agent-workspace/builds/worker-14/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" "MAP_USER_ID=0" "-e" "CARGO_TARGET_DIR=/opt/rustwide/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/opt/rustwide/cargo-home" "-e" "RUSTUP_HOME=/opt/rustwide/rustup-home" "-w" "/opt/rustwide/workdir" "-m" "1610612736" "--network" "none" "rustops/crates-build-env" "/opt/rustwide/cargo-home/bin/cargo" "+41997647ba6a77908f6ef64401414feb00bccf16" "test" "--frozen"`
[INFO] [stderr] WARNING: Your kernel does not support swap limit capabilities or the cgroup is not mounted. Memory limited without swap.
[INFO] [stdout] 198441ca7db8cade93d3254b5d5069a61c5c4590ba902224216b7d0ceda1e2ef
[INFO] running `"docker" "start" "-a" "198441ca7db8cade93d3254b5d5069a61c5c4590ba902224216b7d0ceda1e2ef"`
[INFO] [stderr] warning: unused variable: `chip8`
[INFO] [stderr]   --> src/main.rs:14:9
[INFO] [stderr]    |
[INFO] [stderr] 14 |     let chip8 = CPU::new(Memory::new());
[INFO] [stderr]    |         ^^^^^ help: if this is intentional, prefix it with an underscore: `_chip8`
[INFO] [stderr]    |
[INFO] [stderr]    = note: `#[warn(unused_variables)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: unused variable: `op`
[INFO] [stderr]   --> src/cpu.rs:23:13
[INFO] [stderr]    |
[INFO] [stderr] 23 |         let op = self.getOP();
[INFO] [stderr]    |             ^^ help: if this is intentional, prefix it with an underscore: `_op`
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `speed`
[INFO] [stderr]  --> src/cpu.rs:5:5
[INFO] [stderr]   |
[INFO] [stderr] 5 |     speed: u16, // 500Hz
[INFO] [stderr]   |     ^^^^^^^^^^
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(dead_code)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `V`
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `I`
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `memory`
[INFO] [stderr]  --> src/cpu.rs:8:5
[INFO] [stderr]   |
[INFO] [stderr] 8 |     memory: Memory,
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: field is never read: `pointer`
[INFO] [stderr]  --> src/cpu.rs:9:5
[INFO] [stderr]   |
[INFO] [stderr] 9 |     pointer: usize
[INFO] [stderr]   |     ^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `run`
[INFO] [stderr]   --> src/cpu.rs:22:5
[INFO] [stderr]    |
[INFO] [stderr] 22 |     pub fn run(&mut self) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `getOP`
[INFO] [stderr]   --> src/cpu.rs:26:5
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: method is never used: `set`
[INFO] [stderr]   --> src/memory.rs:24:5
[INFO] [stderr]    |
[INFO] [stderr] 24 |     pub fn set(&mut self, data: [u8; 3216]) {
[INFO] [stderr]    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `V` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:6:5
[INFO] [stderr]   |
[INFO] [stderr] 6 |     V: [u8; 16], // 16 8bit register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `v`
[INFO] [stderr]   |
[INFO] [stderr]   = note: `#[warn(non_snake_case)]` on by default
[INFO] [stderr] 
[INFO] [stderr] warning: structure field `I` should have a snake case name
[INFO] [stderr]  --> src/cpu.rs:7:5
[INFO] [stderr]   |
[INFO] [stderr] 7 |     I: u16,  // 16bit address register
[INFO] [stderr]   |     ^ help: convert the identifier to snake case (notice the capitalization): `i`
[INFO] [stderr] 
[INFO] [stderr] warning: method `getOP` should have a snake case name
[INFO] [stderr]   --> src/cpu.rs:26:8
[INFO] [stderr]    |
[INFO] [stderr] 26 |     fn getOP(&mut self) -> u16 { // 获取当前CPU指令 并向后2 byte移动指针
[INFO] [stderr]    |        ^^^^^ help: convert the identifier to snake case: `get_op`
[INFO] [stderr] 
[INFO] [stderr] warning: 13 warnings emitted
[INFO] [stderr] 
[INFO] [stderr]     Finished test [unoptimized + debuginfo] target(s) in 0.35s
[INFO] [stderr]      Running /opt/rustwide/target/debug/deps/chip8-73f7e41b4ef34792
[INFO] [stdout] 
[INFO] [stdout] running 0 tests
[INFO] [stdout] 
[INFO] [stdout] test result: ok. 0 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
[INFO] [stdout] 
[INFO] running `"docker" "inspect" "198441ca7db8cade93d3254b5d5069a61c5c4590ba902224216b7d0ceda1e2ef"`
[INFO] running `"docker" "rm" "-f" "198441ca7db8cade93d3254b5d5069a61c5c4590ba902224216b7d0ceda1e2ef"`
[INFO] [stdout] 198441ca7db8cade93d3254b5d5069a61c5c4590ba902224216b7d0ceda1e2ef