Enable more clippy lints and fix some clippy issues

src/atomicmin.rs

@@ -1,6 +1,7 @@
 use std::sync::atomic::AtomicUsize;
 use std::sync::atomic::Ordering::{Relaxed, SeqCst};
 
+#[derive(Debug)]
 pub struct AtomicMin {
     val: AtomicUsize,
 }

src/lib.rs

@@ -1,3 +1,17 @@
+#![warn(trivial_casts, trivial_numeric_casts, unused_import_braces)]
+#![deny(missing_debug_implementations, missing_copy_implementations)]
+#![warn(clippy::expl_impl_clone_on_copy)]
+#![warn(clippy::float_cmp_const)]
+#![warn(clippy::linkedlist)]
+#![warn(clippy::map_flatten)]
+#![warn(clippy::match_same_arms)]
+#![warn(clippy::mem_forget)]
+#![warn(clippy::mut_mut)]
+#![warn(clippy::mutex_integer)]
+#![warn(clippy::needless_continue)]
+#![warn(clippy::path_buf_push_overwrite)]
+#![warn(clippy::range_plus_one)]
+
 use num_cpus;
 #[cfg(feature = "parallel")]
 extern crate rayon;
@@ -427,7 +441,7 @@ pub fn optimize_from_memory(data: &[u8], opts: &Options) -> PngResult<Vec<u8>> {
 
     let deadline = Arc::new(Deadline::new(opts.timeout, opts.verbosity.is_some()));
 
-    let original_size = data.len() as usize;
+    let original_size = data.len();
     let mut png = PngData::from_slice(data, opts.fix_errors)?;
 
     // Run the optimizer on the decoded PNG.
@@ -882,11 +896,10 @@ fn perform_strip(png: &mut PngData, opts: &Options) {
     }
 
     let may_replace_iccp = match opts.strip {
-        Headers::None => false,
         Headers::Keep(ref hdrs) => hdrs.contains("sRGB"),
         Headers::Strip(ref hdrs) => !hdrs.iter().any(|v| v == "sRGB"),
         Headers::Safe => true,
-        Headers::All => false,
+        Headers::None | Headers::All => false,
     };
 
     if may_replace_iccp {

src/main.rs

@@ -1,5 +1,16 @@
 #![warn(trivial_casts, trivial_numeric_casts, unused_import_braces)]
 #![deny(missing_debug_implementations, missing_copy_implementations)]
+#![warn(clippy::expl_impl_clone_on_copy)]
+#![warn(clippy::float_cmp_const)]
+#![warn(clippy::linkedlist)]
+#![warn(clippy::map_flatten)]
+#![warn(clippy::match_same_arms)]
+#![warn(clippy::mem_forget)]
+#![warn(clippy::mut_mut)]
+#![warn(clippy::mutex_integer)]
+#![warn(clippy::needless_continue)]
+#![warn(clippy::path_buf_push_overwrite)]
+#![warn(clippy::range_plus_one)]
 
 use clap::{App, AppSettings, Arg, ArgMatches};
 use oxipng::AlphaOptim;
@@ -264,7 +275,7 @@ fn collect_files(
                 let files = input
                     .read_dir()
                     .unwrap()
-                    .map(|x| x.unwrap().path().to_owned())
+                    .map(|x| x.unwrap().path())
                     .collect();
                 in_out_pairs.extend(collect_files(files, out_dir, out_file, recursive, false));
             } else {

src/png/scan_lines.rs

@@ -129,7 +129,7 @@ impl Iterator for ScanLineRanges {
                 7 => (1, 2),
                 _ => unreachable!(),
             };
-            let mut pixels_per_line = self.width / pixels_factor as u32;
+            let mut pixels_per_line = self.width / pixels_factor;
             // Determine whether to add pixels if there is a final, incomplete 8x8 block
             let gap = self.width % pixels_factor;
             match pass.0 {

src/reduction/alpha.rs

@@ -215,9 +215,9 @@ pub fn reduced_alpha_channel(png: &PngImage) -> Option<PngImage> {
         for (i, &byte) in line.data.iter().enumerate() {
             if i as u8 & bpp_mask >= colored_bytes {
                 continue;
-            } else {
-                raw_data.push(byte);
             }
+
+            raw_data.push(byte);
         }
     }