tidy: fix most clippy warnings

src/tools/tidy/src/debug_artifacts.rs

@@ -2,7 +2,7 @@
 
 use std::path::{Path, PathBuf};
 
-const GRAPHVIZ_POSTFLOW_MSG: &'static str = "`borrowck_graphviz_postflow` attribute in test";
+const GRAPHVIZ_POSTFLOW_MSG: &str = "`borrowck_graphviz_postflow` attribute in test";
 
 pub fn check(path: &Path, bad: &mut bool) {
     let test_dir: PathBuf = path.join("test");

src/tools/tidy/src/error_codes_check.rs

@@ -53,7 +53,7 @@ fn extract_error_codes(f: &str, error_codes: &mut HashMap<String, bool>, path: &
                     error_codes.insert(err_code.clone(), false);
                 }
                 // Now we extract the tests from the markdown file!
-                let md = some_or_continue!(s.splitn(2, "include_str!(\"").skip(1).next());
+                let md = some_or_continue!(s.splitn(2, "include_str!(\"").nth(1));
                 let md_file_name = some_or_continue!(md.splitn(2, "\")").next());
                 let path = some_or_continue!(path.parent()).join(md_file_name);
                 match read_to_string(&path) {
@@ -84,7 +84,7 @@ fn extract_error_codes_from_tests(f: &str, error_codes: &mut HashMap<String, boo
         let s = line.trim();
         if s.starts_with("error[E") || s.starts_with("warning[E") {
             if let Some(err_code) = s.splitn(2, ']').next() {
-                if let Some(err_code) = err_code.splitn(2, '[').skip(1).next() {
+                if let Some(err_code) = err_code.splitn(2, '[').nth(1) {
                     let nb = error_codes.entry(err_code.to_owned()).or_insert(false);
                     *nb = true;
                 }

src/tools/tidy/src/features.rs

@@ -232,7 +232,7 @@ fn test_filen_gate(filen_underscore: &str, features: &mut Features) -> bool {
             }
         }
     }
-    return false;
+    false
 }
 
 pub fn collect_lang_features(base_src_path: &Path, bad: &mut bool) -> Features {
@@ -344,7 +344,7 @@ fn collect_lang_features_in(base: &Path, file: &str, bad: &mut bool) -> Features
                 }
                 None
             } else {
-                let s = issue_str.split('(').nth(1).unwrap().split(')').nth(0).unwrap();
+                let s = issue_str.split('(').nth(1).unwrap().split(')').next().unwrap();
                 Some(s.parse().unwrap())
             };
             Some((name.to_owned(), Feature { level, since, has_gate_test: false, tracking_issue }))

src/tools/tidy/src/features/version.rs

@@ -38,7 +38,7 @@ impl FromStr for Version {
 
         let parts = [part()?, part()?, part()?];
 
-        if let Some(_) = iter.next() {
+        if iter.next().is_some() {
             // Ensure we don't have more than 3 parts.
             return Err(ParseVersionError::WrongNumberOfParts);
         }

src/tools/tidy/src/style.rs

@@ -58,7 +58,7 @@ enum LIUState {
 fn line_is_url(columns: usize, line: &str) -> bool {
     // more basic check for error_codes.rs, to avoid complexity in implementing two state machines
     if columns == ERROR_CODE_COLS {
-        return line.starts_with("[") && line.contains("]:") && line.contains("http");
+        return line.starts_with('[') && line.contains("]:") && line.contains("http");
     }
 
     use self::LIUState::*;