fix: update MSRV to 1.70.0

Due to the `home` v0.5.9 release we need at least Rust 1.70.0. Make this the
new minimum supported Rust version. As 1.70.0 is already >1 year old, I dare
to release this as a bugfix release.

New lints were introduced, those are also fixed in this commit.

Fixes #54.

ec-gpu-gen/Cargo.toml

@@ -7,7 +7,7 @@ description = "Code generator for field and eliptic curve operations on the GPUs
 homepage = "https://github.com/filecoin-project/ff-cl-gen"
 repository = "https://github.com/filecoin-project/ff-cl-gen"
 license = "MIT/Apache-2.0"
-rust-version = "1.62.1"
+rust-version = "1.70.0"
 
 [dependencies]
 bitvec = "1.0.1"

ec-gpu-gen/src/fft_cpu.rs

@@ -29,7 +29,7 @@ pub fn serial_fft<F: PrimeField>(a: &mut [F], omega: &F, log_n: u32) {
 
     let mut m = 1;
     for _ in 0..log_n {
-        let w_m = omega.pow_vartime(&[u64::from(n / (2 * m))]);
+        let w_m = omega.pow_vartime([u64::from(n / (2 * m))]);
 
         let mut k = 0;
         while k < n {
@@ -68,16 +68,16 @@ pub fn parallel_fft<F: PrimeField>(
     let num_threads = 1 << log_threads;
     let log_new_n = log_n - log_threads;
     let mut tmp = vec![vec![F::ZERO; 1 << log_new_n]; num_threads];
-    let new_omega = omega.pow_vartime(&[num_threads as u64]);
+    let new_omega = omega.pow_vartime([num_threads as u64]);
 
     worker.scope(0, |scope, _| {
         let a = &*a;
 
         for (j, tmp) in tmp.iter_mut().enumerate() {
             scope.execute(move || {
                 // Shuffle into a sub-FFT
-                let omega_j = omega.pow_vartime(&[j as u64]);
-                let omega_step = omega.pow_vartime(&[(j as u64) << log_new_n]);
+                let omega_j = omega.pow_vartime([j as u64]);
+                let omega_step = omega.pow_vartime([(j as u64) << log_new_n]);
 
                 let mut elt = F::ONE;
                 for (i, tmp) in tmp.iter_mut().enumerate() {

ec-gpu-gen/src/source.rs

@@ -683,7 +683,7 @@ fn generate_opencl(source_builder: &SourceBuilder) -> PathBuf {
     // build.
     let source_path: PathBuf = [&out_dir, "kernel.cl"].iter().collect();
 
-    fs::write(&source_path, &kernel_source).unwrap_or_else(|_| {
+    fs::write(&source_path, kernel_source).unwrap_or_else(|_| {
         panic!(
             "Cannot write kernel source at {}.",
             source_path.to_str().unwrap()

rust-toolchain

@@ -1 +1 @@
-1.62.1
+1.70.0