Oct 21 21:46:30.610 INFO checking DamirGadiev/su-matrix against master#155510e377ae2a8d8ee0dad1a5f809c9062a5526 for pr-55192
Oct 21 21:46:30.610 INFO running `"docker" "create" "-v" "/mnt/big/crater/./work/local/target-dirs/pr-55192/worker-7/master#155510e377ae2a8d8ee0dad1a5f809c9062a5526:/target:rw,Z" "-v" "/mnt/big/crater/./work/local/test-source/worker-7/pr-55192/master#155510e377ae2a8d8ee0dad1a5f809c9062a5526:/source:ro,Z" "-v" "/mnt/big/crater/./work/local/cargo-home:/cargo-home:ro,Z" "-v" "/mnt/big/crater/./work/local/rustup-home:/rustup-home:ro,Z" "-e" "USER_ID=1000" "-e" "SOURCE_DIR=/source" "-e" "USER_ID=1000" "-e" "CMD=cargo +155510e377ae2a8d8ee0dad1a5f809c9062a5526-alt check --frozen --all --all-targets" "-e" "CARGO_TARGET_DIR=/target" "-e" "CARGO_INCREMENTAL=0" "-e" "RUST_BACKTRACE=full" "-e" "RUSTFLAGS=--cap-lints=forbid" "-e" "CARGO_HOME=/cargo-home" "-e" "RUSTUP_HOME=/rustup-home" "-m" "1536M" "--network" "none" "crater"`
Oct 21 21:46:30.962 INFO blam! 92a36a83b3a99d9ddfabe2ef10b1ab11745875c4fa0ef58c1c37bf1e060221a6
Oct 21 21:46:30.969 INFO running `"docker" "start" "-a" "92a36a83b3a99d9ddfabe2ef10b1ab11745875c4fa0ef58c1c37bf1e060221a6"`
Oct 21 21:46:32.039 INFO kablam! usermod: no changes
Oct 21 21:46:32.113 INFO kablam!     Checking alga v0.5.3
Oct 21 21:46:36.560 INFO kablam!     Checking nalgebra v0.14.0
Oct 21 21:47:02.612 INFO kablam!     Checking su-matrix v0.1.0 (/source)
Oct 21 21:47:03.623 INFO kablam! warning: type alias is never used: `ComplexMatrix2x2f`
Oct 21 21:47:03.623 INFO kablam!  --> src/su_matrix.rs:8:5
Oct 21 21:47:03.623 INFO kablam!   |
Oct 21 21:47:03.623 INFO kablam! 8 |     type ComplexMatrix2x2f = Matrix<Complex<f64>, U2, U2, MatrixArray<Complex<f64>, U2, U2>>;
Oct 21 21:47:03.623 INFO kablam!   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.623 INFO kablam!   |
Oct 21 21:47:03.623 INFO kablam!   = note: #[warn(dead_code)] on by default
Oct 21 21:47:03.623 INFO kablam! 
Oct 21 21:47:03.623 INFO kablam! warning: function is never used: `calculate_determinant`
Oct 21 21:47:03.623 INFO kablam!   --> src/su_matrix.rs:11:5
Oct 21 21:47:03.623 INFO kablam!    |
Oct 21 21:47:03.623 INFO kablam! 11 |     pub fn calculate_determinant(matrix: &ComplexMatrix2x2f) -> Complex<f64> {
Oct 21 21:47:03.623 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.623 INFO kablam! 
Oct 21 21:47:03.623 INFO kablam! warning: function is never used: `inverse_determinant`
Oct 21 21:47:03.623 INFO kablam!   --> src/su_matrix.rs:20:5
Oct 21 21:47:03.623 INFO kablam!    |
Oct 21 21:47:03.624 INFO kablam! 20 |     pub fn inverse_determinant(det: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:03.624 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.624 INFO kablam! 
Oct 21 21:47:03.624 INFO kablam! warning: function is never used: `inverse_sign`
Oct 21 21:47:03.624 INFO kablam!   --> src/su_matrix.rs:25:5
Oct 21 21:47:03.624 INFO kablam!    |
Oct 21 21:47:03.624 INFO kablam! 25 |     pub fn inverse_sign(a: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:03.624 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.624 INFO kablam! 
Oct 21 21:47:03.624 INFO kablam! warning: function is never used: `matrix_inversion`
Oct 21 21:47:03.624 INFO kablam!   --> src/su_matrix.rs:30:5
Oct 21 21:47:03.624 INFO kablam!    |
Oct 21 21:47:03.624 INFO kablam! 30 |     pub fn matrix_inversion(matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:03.624 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.624 INFO kablam! 
Oct 21 21:47:03.624 INFO kablam! warning: function is never used: `matrix_power`
Oct 21 21:47:03.624 INFO kablam!   --> src/su_matrix.rs:48:5
Oct 21 21:47:03.624 INFO kablam!    |
Oct 21 21:47:03.624 INFO kablam! 48 |     pub fn matrix_power(power: u64, matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:03.624 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:03.624 INFO kablam! 
Oct 21 21:47:04.128 INFO kablam! warning: function is never used: `matrix_power`
Oct 21 21:47:04.128 INFO kablam!   --> src/su_matrix.rs:48:5
Oct 21 21:47:04.128 INFO kablam!    |
Oct 21 21:47:04.128 INFO kablam! 48 |     pub fn matrix_power(power: u64, matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:04.128 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.128 INFO kablam!    |
Oct 21 21:47:04.128 INFO kablam!    = note: #[warn(dead_code)] on by default
Oct 21 21:47:04.128 INFO kablam! 
Oct 21 21:47:04.880 INFO kablam! warning: unused variable: `length`
Oct 21 21:47:04.880 INFO kablam!   --> src/main.rs:18:25
Oct 21 21:47:04.880 INFO kablam!    |
Oct 21 21:47:04.880 INFO kablam! 18 | fn calculate_resistance(length: f64, m: f64, a: f64, plank_const: f64, energy: f64, potential: f64, n: u64) ->f64 {
Oct 21 21:47:04.880 INFO kablam!    |                         ^^^^^^ help: consider using `_length` instead
Oct 21 21:47:04.880 INFO kablam!    |
Oct 21 21:47:04.880 INFO kablam!    = note: #[warn(unused_variables)] on by default
Oct 21 21:47:04.881 INFO kablam! 
Oct 21 21:47:04.892 INFO kablam! warning: type alias is never used: `ComplexMatrix2x2f`
Oct 21 21:47:04.892 INFO kablam!  --> src/su_matrix.rs:8:5
Oct 21 21:47:04.893 INFO kablam!   |
Oct 21 21:47:04.893 INFO kablam! 8 |     type ComplexMatrix2x2f = Matrix<Complex<f64>, U2, U2, MatrixArray<Complex<f64>, U2, U2>>;
Oct 21 21:47:04.893 INFO kablam!   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.893 INFO kablam!   |
Oct 21 21:47:04.893 INFO kablam!   = note: #[warn(dead_code)] on by default
Oct 21 21:47:04.893 INFO kablam! 
Oct 21 21:47:04.893 INFO kablam! warning: function is never used: `calculate_determinant`
Oct 21 21:47:04.893 INFO kablam!   --> src/su_matrix.rs:11:5
Oct 21 21:47:04.893 INFO kablam!    |
Oct 21 21:47:04.893 INFO kablam! 11 |     pub fn calculate_determinant(matrix: &ComplexMatrix2x2f) -> Complex<f64> {
Oct 21 21:47:04.893 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.893 INFO kablam! 
Oct 21 21:47:04.893 INFO kablam! warning: function is never used: `inverse_determinant`
Oct 21 21:47:04.893 INFO kablam!   --> src/su_matrix.rs:20:5
Oct 21 21:47:04.893 INFO kablam!    |
Oct 21 21:47:04.893 INFO kablam! 20 |     pub fn inverse_determinant(det: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:04.893 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.893 INFO kablam! 
Oct 21 21:47:04.893 INFO kablam! warning: function is never used: `inverse_sign`
Oct 21 21:47:04.893 INFO kablam!   --> src/su_matrix.rs:25:5
Oct 21 21:47:04.893 INFO kablam!    |
Oct 21 21:47:04.893 INFO kablam! 25 |     pub fn inverse_sign(a: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:04.893 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.893 INFO kablam! 
Oct 21 21:47:04.894 INFO kablam! warning: function is never used: `matrix_inversion`
Oct 21 21:47:04.894 INFO kablam!   --> src/su_matrix.rs:30:5
Oct 21 21:47:04.894 INFO kablam!    |
Oct 21 21:47:04.894 INFO kablam! 30 |     pub fn matrix_inversion(matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:04.894 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.894 INFO kablam! 
Oct 21 21:47:04.894 INFO kablam! warning: function is never used: `matrix_power`
Oct 21 21:47:04.894 INFO kablam!   --> src/su_matrix.rs:48:5
Oct 21 21:47:04.894 INFO kablam!    |
Oct 21 21:47:04.894 INFO kablam! 48 |     pub fn matrix_power(power: u64, matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:04.894 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.894 INFO kablam! 
Oct 21 21:47:04.894 INFO kablam! warning: type alias is never used: `ComplexMatrix2x2f`
Oct 21 21:47:04.894 INFO kablam!   --> src/main.rs:16:1
Oct 21 21:47:04.894 INFO kablam!    |
Oct 21 21:47:04.894 INFO kablam! 16 | type ComplexMatrix2x2f = Matrix<Complex<f64>, U2, U2, MatrixArray<Complex<f64>, U2, U2>>;
Oct 21 21:47:04.894 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.894 INFO kablam! 
Oct 21 21:47:04.894 INFO kablam! warning: function is never used: `calculate_resistance`
Oct 21 21:47:04.894 INFO kablam!   --> src/main.rs:18:1
Oct 21 21:47:04.894 INFO kablam!    |
Oct 21 21:47:04.894 INFO kablam! 18 | fn calculate_resistance(length: f64, m: f64, a: f64, plank_const: f64, energy: f64, potential: f64, n: u64) ->f64 {
Oct 21 21:47:04.895 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.895 INFO kablam! 
Oct 21 21:47:04.895 INFO kablam! warning: function is never used: `calculate_resistance_from_a`
Oct 21 21:47:04.895 INFO kablam!   --> src/main.rs:66:1
Oct 21 21:47:04.895 INFO kablam!    |
Oct 21 21:47:04.895 INFO kablam! 66 | fn calculate_resistance_from_a() {
Oct 21 21:47:04.895 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.895 INFO kablam! 
Oct 21 21:47:04.895 INFO kablam! warning: function is never used: `calculate_resistance_from_energy`
Oct 21 21:47:04.895 INFO kablam!   --> src/main.rs:90:1
Oct 21 21:47:04.895 INFO kablam!    |
Oct 21 21:47:04.895 INFO kablam! 90 | fn calculate_resistance_from_energy() {
Oct 21 21:47:04.895 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.895 INFO kablam! 
Oct 21 21:47:04.895 INFO kablam! warning: function is never used: `calculate_resistance_from_potential`
Oct 21 21:47:04.895 INFO kablam!    --> src/main.rs:115:1
Oct 21 21:47:04.895 INFO kablam!     |
Oct 21 21:47:04.895 INFO kablam! 115 | fn calculate_resistance_from_potential() {
Oct 21 21:47:04.895 INFO kablam!     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:04.895 INFO kablam! 
Oct 21 21:47:05.081 INFO kablam! warning: unused variable: `length`
Oct 21 21:47:05.081 INFO kablam!   --> src/main.rs:18:25
Oct 21 21:47:05.081 INFO kablam!    |
Oct 21 21:47:05.081 INFO kablam! 18 | fn calculate_resistance(length: f64, m: f64, a: f64, plank_const: f64, energy: f64, potential: f64, n: u64) ->f64 {
Oct 21 21:47:05.081 INFO kablam!    |                         ^^^^^^ help: consider using `_length` instead
Oct 21 21:47:05.081 INFO kablam!    |
Oct 21 21:47:05.081 INFO kablam!    = note: #[warn(unused_variables)] on by default
Oct 21 21:47:05.081 INFO kablam! 
Oct 21 21:47:05.092 INFO kablam! warning: type alias is never used: `ComplexMatrix2x2f`
Oct 21 21:47:05.092 INFO kablam!  --> src/su_matrix.rs:8:5
Oct 21 21:47:05.092 INFO kablam!   |
Oct 21 21:47:05.092 INFO kablam! 8 |     type ComplexMatrix2x2f = Matrix<Complex<f64>, U2, U2, MatrixArray<Complex<f64>, U2, U2>>;
Oct 21 21:47:05.092 INFO kablam!   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.092 INFO kablam!   |
Oct 21 21:47:05.092 INFO kablam!   = note: #[warn(dead_code)] on by default
Oct 21 21:47:05.093 INFO kablam! 
Oct 21 21:47:05.093 INFO kablam! warning: function is never used: `calculate_determinant`
Oct 21 21:47:05.093 INFO kablam!   --> src/su_matrix.rs:11:5
Oct 21 21:47:05.093 INFO kablam!    |
Oct 21 21:47:05.093 INFO kablam! 11 |     pub fn calculate_determinant(matrix: &ComplexMatrix2x2f) -> Complex<f64> {
Oct 21 21:47:05.093 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.093 INFO kablam! 
Oct 21 21:47:05.093 INFO kablam! warning: function is never used: `inverse_determinant`
Oct 21 21:47:05.093 INFO kablam!   --> src/su_matrix.rs:20:5
Oct 21 21:47:05.093 INFO kablam!    |
Oct 21 21:47:05.093 INFO kablam! 20 |     pub fn inverse_determinant(det: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:05.093 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.093 INFO kablam! 
Oct 21 21:47:05.093 INFO kablam! warning: function is never used: `inverse_sign`
Oct 21 21:47:05.093 INFO kablam!   --> src/su_matrix.rs:25:5
Oct 21 21:47:05.093 INFO kablam!    |
Oct 21 21:47:05.093 INFO kablam! 25 |     pub fn inverse_sign(a: &Complex<f64>) -> Complex<f64> {
Oct 21 21:47:05.093 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.093 INFO kablam! 
Oct 21 21:47:05.093 INFO kablam! warning: function is never used: `matrix_inversion`
Oct 21 21:47:05.094 INFO kablam!   --> src/su_matrix.rs:30:5
Oct 21 21:47:05.094 INFO kablam!    |
Oct 21 21:47:05.094 INFO kablam! 30 |     pub fn matrix_inversion(matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:05.094 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.094 INFO kablam! 
Oct 21 21:47:05.094 INFO kablam! warning: function is never used: `matrix_power`
Oct 21 21:47:05.094 INFO kablam!   --> src/su_matrix.rs:48:5
Oct 21 21:47:05.094 INFO kablam!    |
Oct 21 21:47:05.094 INFO kablam! 48 |     pub fn matrix_power(power: u64, matrix: &ComplexMatrix2x2f) -> ComplexMatrix2x2f {
Oct 21 21:47:05.094 INFO kablam!    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.094 INFO kablam! 
Oct 21 21:47:05.094 INFO kablam! warning: type alias is never used: `ComplexMatrix2x2f`
Oct 21 21:47:05.094 INFO kablam!   --> src/main.rs:16:1
Oct 21 21:47:05.094 INFO kablam!    |
Oct 21 21:47:05.094 INFO kablam! 16 | type ComplexMatrix2x2f = Matrix<Complex<f64>, U2, U2, MatrixArray<Complex<f64>, U2, U2>>;
Oct 21 21:47:05.094 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.094 INFO kablam! 
Oct 21 21:47:05.094 INFO kablam! warning: function is never used: `calculate_resistance`
Oct 21 21:47:05.094 INFO kablam!   --> src/main.rs:18:1
Oct 21 21:47:05.094 INFO kablam!    |
Oct 21 21:47:05.094 INFO kablam! 18 | fn calculate_resistance(length: f64, m: f64, a: f64, plank_const: f64, energy: f64, potential: f64, n: u64) ->f64 {
Oct 21 21:47:05.094 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.094 INFO kablam! 
Oct 21 21:47:05.095 INFO kablam! warning: function is never used: `calculate_resistance_from_a`
Oct 21 21:47:05.095 INFO kablam!   --> src/main.rs:66:1
Oct 21 21:47:05.095 INFO kablam!    |
Oct 21 21:47:05.095 INFO kablam! 66 | fn calculate_resistance_from_a() {
Oct 21 21:47:05.095 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.095 INFO kablam! 
Oct 21 21:47:05.095 INFO kablam! warning: function is never used: `calculate_resistance_from_energy`
Oct 21 21:47:05.095 INFO kablam!   --> src/main.rs:90:1
Oct 21 21:47:05.095 INFO kablam!    |
Oct 21 21:47:05.095 INFO kablam! 90 | fn calculate_resistance_from_energy() {
Oct 21 21:47:05.095 INFO kablam!    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.095 INFO kablam! 
Oct 21 21:47:05.095 INFO kablam! warning: function is never used: `calculate_resistance_from_potential`
Oct 21 21:47:05.095 INFO kablam!    --> src/main.rs:115:1
Oct 21 21:47:05.095 INFO kablam!     |
Oct 21 21:47:05.095 INFO kablam! 115 | fn calculate_resistance_from_potential() {
Oct 21 21:47:05.095 INFO kablam!     | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Oct 21 21:47:05.095 INFO kablam! 
Oct 21 21:47:05.143 INFO kablam!     Finished dev [unoptimized + debuginfo] target(s) in 33.09s
Oct 21 21:47:05.143 INFO kablam! su: No module specific data is present
Oct 21 21:47:05.940 INFO running `"docker" "rm" "-f" "92a36a83b3a99d9ddfabe2ef10b1ab11745875c4fa0ef58c1c37bf1e060221a6"`
Oct 21 21:47:06.209 INFO blam! 92a36a83b3a99d9ddfabe2ef10b1ab11745875c4fa0ef58c1c37bf1e060221a6