diff --git a/bin/src/config.rs b/bin/src/config.rs
index a03c047..d235857 100644
--- a/bin/src/config.rs
+++ b/bin/src/config.rs
@@ -317,7 +317,7 @@ impl ConfFile {
     }
     pub fn lints(&self) -> LintMap {
         utils::lint_map_of(
-            (&*LINTS)
+            (*LINTS)
                 .iter()
                 .filter(|l| !self.disabled.iter().any(|check| check == l.name()))
                 .cloned()
@@ -329,10 +329,7 @@ impl ConfFile {
         if let Some(v) = &self.nix_version {
             v.parse::<Version>()
                 .map_err(|_| ConfigErr::ConfFileVersionParse(v.clone()))
-        } else if let Some(v) = utils::get_version_info()
-            .map(|o| o.parse::<Version>().ok())
-            .flatten()
-        {
+        } else if let Some(v) = utils::get_version_info().and_then(|o| o.parse::<Version>().ok()) {
             Ok(v)
         } else {
             Ok(utils::default_nix_version().parse::<Version>().unwrap())
@@ -374,9 +371,9 @@ fn parse_warning_code(src: &str) -> Result<u32, ConfigErr> {
 fn vfs(files: Vec<PathBuf>) -> Result<ReadOnlyVfs, ConfigErr> {
     let mut vfs = ReadOnlyVfs::default();
     for file in files.iter() {
-        if let Ok(data) = fs::read_to_string(&file) {
-            let _id = vfs.alloc_file_id(&file);
-            vfs.set_file_contents(&file, data.as_bytes());
+        if let Ok(data) = fs::read_to_string(file) {
+            let _id = vfs.alloc_file_id(file);
+            vfs.set_file_contents(file, data.as_bytes());
         } else {
             println!("`{}` contains non-utf8 content", file.display());
         };
diff --git a/bin/src/fix/all.rs b/bin/src/fix/all.rs
index d7f7fff..3ddd6aa 100644
--- a/bin/src/fix/all.rs
+++ b/bin/src/fix/all.rs
@@ -61,7 +61,7 @@ fn reorder(mut reports: Vec<Report>) -> Vec<Report> {
 impl<'a> Iterator for FixResult<'a> {
     type Item = FixResult<'a>;
     fn next(&mut self) -> Option<Self::Item> {
-        let all_reports = collect_fixes(&self.src, self.lints, &self.sess).ok()?;
+        let all_reports = collect_fixes(&self.src, self.lints, self.sess).ok()?;
         if all_reports.is_empty() {
             return None;
         }
diff --git a/bin/src/fix/single.rs b/bin/src/fix/single.rs
index 67b6b8f..e162a94 100644
--- a/bin/src/fix/single.rs
+++ b/bin/src/fix/single.rs
@@ -49,15 +49,15 @@ fn find(offset: TextSize, src: &str, sess: &SessionInfo) -> Result<Report, Singl
         .ok_or(SingleFixErr::NoOp)
 }
 
-pub fn single<'a, 'b>(
+pub fn single<'a>(
     line: usize,
     col: usize,
     src: &'a str,
-    sess: &'b SessionInfo,
+    sess: &SessionInfo,
 ) -> Result<SingleFixResult<'a>, SingleFixErr> {
     let mut src = Cow::from(src);
-    let offset = pos_to_byte(line, col, &*src)?;
-    let report = find(offset, &*src, &sess)?;
+    let offset = pos_to_byte(line, col, &src)?;
+    let report = find(offset, &src, sess)?;
 
     report.apply(src.to_mut());
 
diff --git a/bin/src/lint.rs b/bin/src/lint.rs
index b7529ba..cfa9e5d 100644
--- a/bin/src/lint.rs
+++ b/bin/src/lint.rs
@@ -36,7 +36,7 @@ pub fn lint_with(vfs_entry: VfsEntry, lints: &LintMap, sess: &SessionInfo) -> Li
 }
 
 pub fn lint(vfs_entry: VfsEntry, sess: &SessionInfo) -> LintResult {
-    lint_with(vfs_entry, &utils::lint_map(), &sess)
+    lint_with(vfs_entry, &utils::lint_map(), sess)
 }
 
 pub mod main {
@@ -68,9 +68,9 @@ pub mod main {
             .filter(|lr| !lr.reports.is_empty())
             .collect::<Vec<_>>();
 
-        if results.len() != 0 {
+        if !results.is_empty() {
             for r in &results {
-                stdout.write(&r, &vfs, check_config.format).unwrap();
+                stdout.write(r, &vfs, check_config.format).unwrap();
             }
             std::process::exit(1);
         }
diff --git a/bin/src/list.rs b/bin/src/list.rs
index 4fe3039..c8d422b 100644
--- a/bin/src/list.rs
+++ b/bin/src/list.rs
@@ -4,8 +4,8 @@ pub mod main {
     use lib::LINTS;
 
     pub fn main() -> Result<(), StatixErr> {
-        let mut lints = (&*LINTS).clone();
-        lints.as_mut_slice().sort_by(|a, b| a.code().cmp(&b.code()));
+        let mut lints = (*LINTS).clone();
+        lints.as_mut_slice().sort_by_key(|a| a.code());
         for l in lints {
             println!("W{:02} {}", l.code(), l.name());
         }
diff --git a/bin/src/session.rs b/bin/src/session.rs
index e69de29..8b13789 100644
--- a/bin/src/session.rs
+++ b/bin/src/session.rs
@@ -0,0 +1 @@
+
diff --git a/bin/src/utils.rs b/bin/src/utils.rs
index d3bff54..490d098 100644
--- a/bin/src/utils.rs
+++ b/bin/src/utils.rs
@@ -20,7 +20,7 @@ pub fn lint_map_of(
 }
 
 pub fn lint_map() -> HashMap<SyntaxKind, Vec<&'static Box<dyn Lint>>> {
-    lint_map_of(&*LINTS)
+    lint_map_of(&LINTS)
 }
 
 pub fn get_version_info() -> Option<String> {
diff --git a/lib/src/lints/bool_comparison.rs b/lib/src/lints/bool_comparison.rs
index 5402f31..fd2a410 100644
--- a/lib/src/lints/bool_comparison.rs
+++ b/lib/src/lints/bool_comparison.rs
@@ -107,10 +107,9 @@ enum NixBoolean {
 // not entirely accurate, underhanded nix programmers might write `true = false`
 fn boolean_ident(node: &SyntaxNode) -> Option<NixBoolean> {
     Ident::cast(node.clone())
-        .map(|ident_expr| match ident_expr.as_str() {
+        .and_then(|ident_expr| match ident_expr.as_str() {
             "true" => Some(NixBoolean::True),
             "false" => Some(NixBoolean::False),
             _ => None,
         })
-        .flatten()
 }
diff --git a/lib/src/lints/bool_simplification.rs b/lib/src/lints/bool_simplification.rs
index 9ccb1f6..a5582ab 100644
--- a/lib/src/lints/bool_simplification.rs
+++ b/lib/src/lints/bool_simplification.rs
@@ -38,7 +38,7 @@ impl Rule for BoolSimplification {
             if let Some(unary_expr) = UnaryOp::cast(node.clone());
             if unary_expr.operator() == UnaryOpKind::Invert;
             if let Some(value_expr) = unary_expr.value();
-            if let Some(paren_expr) = Paren::cast(value_expr.clone());
+            if let Some(paren_expr) = Paren::cast(value_expr);
             if let Some(inner_expr) = paren_expr.inner();
             if let Some(bin_expr) = BinOp::cast(inner_expr);
             if let Some(BinOpKind::Equal) = bin_expr.operator();
diff --git a/lib/src/lints/empty_pattern.rs b/lib/src/lints/empty_pattern.rs
index 14c3b5e..163528b 100644
--- a/lib/src/lints/empty_pattern.rs
+++ b/lib/src/lints/empty_pattern.rs
@@ -48,7 +48,7 @@ impl Rule for EmptyPattern {
             if let Some(arg) = lambda_expr.arg();
             if let Some(body) = lambda_expr.body();
 
-            if let Some(pattern) = Pattern::cast(arg.clone());
+            if let Some(pattern) = Pattern::cast(arg);
 
             // no patterns within `{ }`
             if pattern.entries().count() == 0;
@@ -75,8 +75,7 @@ fn is_module(body: &SyntaxNode) -> bool {
         if let Some(attr_set) = AttrSet::cast(body.clone());
         if attr_set
             .entries()
-            .map(|e| e.key())
-            .flatten()
+            .filter_map(|e| e.key())
             .any(|k| k.node().to_string() == "imports");
         then {
             true
diff --git a/lib/src/lints/faster_groupby.rs b/lib/src/lints/faster_groupby.rs
index 2a36f5f..619af3d 100644
--- a/lib/src/lints/faster_groupby.rs
+++ b/lib/src/lints/faster_groupby.rs
@@ -50,8 +50,8 @@ impl Rule for FasterGroupBy {
 
             // a heuristic to lint on nixpkgs.lib.groupBy
             // and lib.groupBy and its variants
-            if select_from.text().to_string() != "builtins";
-            if group_by_attr.text().to_string() == "groupBy";
+            if select_from.text() != "builtins";
+            if group_by_attr.text() == "groupBy";
 
             then {
                 let at = node.text_range();
diff --git a/lib/src/lints/faster_zipattrswith.rs b/lib/src/lints/faster_zipattrswith.rs
index 139d499..23faf5e 100644
--- a/lib/src/lints/faster_zipattrswith.rs
+++ b/lib/src/lints/faster_zipattrswith.rs
@@ -50,8 +50,8 @@ impl Rule for FasterZipAttrsWith {
 
             // a heuristic to lint on nixpkgs.lib.zipAttrsWith
             // and lib.zipAttrsWith and its variants
-            if select_from.text().to_string() != "builtins";
-            if zip_attrs_with.text().to_string() == "zipAttrsWith";
+            if select_from.text() != "builtins";
+            if zip_attrs_with.text() == "zipAttrsWith";
 
             then {
                 let at = node.text_range();
diff --git a/lib/src/lints/repeated_keys.rs b/lib/src/lints/repeated_keys.rs
index 71b015a..6b9fef0 100644
--- a/lib/src/lints/repeated_keys.rs
+++ b/lib/src/lints/repeated_keys.rs
@@ -55,7 +55,7 @@ impl Rule for RepeatedKeys {
             if components.next().is_some();
 
             if let Some(parent_node) = node.parent();
-            if let Some(parent_attr_set) = AttrSet::cast(parent_node.clone());
+            if let Some(parent_attr_set) = AttrSet::cast(parent_node);
 
             if !parent_attr_set.recursive();
             let occurrences = parent_attr_set.entries().filter_map(|kv_scrutinee| {
@@ -92,8 +92,8 @@ impl Rule for RepeatedKeys {
                 let third_message = {
                     let remaining_occurrences = iter.count();
                     let mut message = match remaining_occurrences {
-                        0 => format!("... and here."),
-                        1 => format!("... and here (`1` occurrence omitted)."),
+                        0 => "... and here.".to_string(),
+                        1 => "... and here (`1` occurrence omitted).".to_string(),
                         n => format!("... and here (`{}` occurrences omitted).", n),
                     };
                     message.push_str(&format!(" Try `{} = {{ {}=...; {}=...; {}=...; }}` instead.", first_component_ident.as_str(), first_subkey, second_subkey, third_subkey));
diff --git a/lib/src/lints/useless_has_attr.rs b/lib/src/lints/useless_has_attr.rs
index 2dbdb5b..22c5fc8 100644
--- a/lib/src/lints/useless_has_attr.rs
+++ b/lib/src/lints/useless_has_attr.rs
@@ -39,7 +39,7 @@ impl Rule for UselessHasAttr {
             if let Some(if_else_expr) = IfElse::cast(node.clone());
             if let Some(condition_expr) = if_else_expr.condition();
             if let Some(default_expr) = if_else_expr.else_body();
-            if let Some(cond_bin_expr) = BinOp::cast(condition_expr.clone());
+            if let Some(cond_bin_expr) = BinOp::cast(condition_expr);
             if let Some(BinOpKind::IsSet) = cond_bin_expr.operator();
 
             // set ? attr_path
@@ -50,7 +50,7 @@ impl Rule for UselessHasAttr {
 
             // check if body of the `if` expression is of the form `set.attr_path`
             if let Some(body_expr) = if_else_expr.body();
-            if let Some(body_select_expr) = Select::cast(body_expr.clone());
+            if let Some(body_select_expr) = Select::cast(body_expr);
             let expected_body = make::select(&set, &attr_path);
 
             // text comparison will do for now
diff --git a/lib/src/make.rs b/lib/src/make.rs
index 2c33ac8..e58a764 100644
--- a/lib/src/make.rs
+++ b/lib/src/make.rs
@@ -7,7 +7,8 @@ use rnix::{
 
 fn ast_from_text<N: TypedNode>(text: &str) -> N {
     let parse = rnix::parse(text);
-    let node = match parse.node().descendants().find_map(N::cast) {
+
+    match parse.node().descendants().find_map(N::cast) {
         Some(it) => it,
         None => {
             panic!(
@@ -16,8 +17,7 @@ fn ast_from_text<N: TypedNode>(text: &str) -> N {
                 text
             )
         }
-    };
-    node
+    }
 }
 
 pub fn parenthesize(node: &SyntaxNode) -> types::Paren {
diff --git a/lib/src/session.rs b/lib/src/session.rs
index 0fb8ae2..f5a7bae 100644
--- a/lib/src/session.rs
+++ b/lib/src/session.rs
@@ -22,7 +22,7 @@ impl PartialOrd for Version {
 
 fn parse_number(s: &str) -> Option<u16> {
     s.chars()
-        .take_while(|c| c.is_digit(10))
+        .take_while(|c| c.is_ascii_digit())
         .collect::<String>()
         .parse::<u16>()
         .ok()
@@ -32,7 +32,7 @@ fn parse_version(s: &str) -> Option<Version> {
     let mut parts = s.split('.');
     let major = parse_number(parts.next()?)?;
     let minor = parse_number(parts.next()?)?;
-    let patch = parts.next().map(|p| parse_number(p)).flatten();
+    let patch = parts.next().and_then(parse_number);
     Some(Version {
         major,
         minor,
diff --git a/macros/src/metadata.rs b/macros/src/metadata.rs
index 98e2a72..72739af 100644
--- a/macros/src/metadata.rs
+++ b/macros/src/metadata.rs
@@ -83,29 +83,29 @@ impl<'μ> LintMeta<'μ> {
 
     fn generate_name_fn(&self) -> TokenStream2 {
         let name_str = self.name;
-        return quote! {
+        quote! {
             fn name(&self) -> &'static str {
                 #name_str
             }
-        };
+        }
     }
 
     fn generate_note_fn(&self) -> TokenStream2 {
         let note_str = self.note;
-        return quote! {
+        quote! {
             fn note(&self) -> &'static str {
                 #note_str
             }
-        };
+        }
     }
 
     fn generate_code_fn(&self) -> TokenStream2 {
         let code_int = self.code;
-        return quote! {
+        quote! {
             fn code(&self) -> u32 {
                 #code_int
             }
-        };
+        }
     }
 
     fn generate_match_with_fn(&self) -> TokenStream2 {
diff --git a/vfs/src/lib.rs b/vfs/src/lib.rs
index 2d7577d..b0a0929 100644
--- a/vfs/src/lib.rs
+++ b/vfs/src/lib.rs
@@ -65,7 +65,7 @@ impl ReadOnlyVfs {
         self.data.insert(file_id, contents.to_owned());
     }
     pub fn iter(&self) -> impl Iterator<Item = VfsEntry> {
-        self.data.iter().map(move |(file_id, _)| VfsEntry {
+        self.data.keys().map(move |file_id| VfsEntry {
             file_id: *file_id,
             file_path: self.file_path(*file_id),
             contents: self.get_str(*file_id),