diff --git a/pango-lexer/src/fsm/nfa/model.rs b/pango-lexer/src/fsm/nfa/model.rs
index f0bf32b..f484a84 100644
--- a/pango-lexer/src/fsm/nfa/model.rs
+++ b/pango-lexer/src/fsm/nfa/model.rs
@@ -237,7 +237,7 @@ impl NfaBuilder {
         self.get_state_mut(start)
             .transitions
             .entry(input)
-            .or_insert(HashSet::new())
+            .or_default()
             .insert(end);
     }
 
@@ -254,7 +254,7 @@ impl NfaBuilder {
         self.get_state_mut(id)
             .transitions
             .entry(Input::Quantified(quantifier))
-            .or_insert_with(HashSet::new)
+            .or_default()
             .insert(quantifier_done);
 
         id
@@ -294,7 +294,7 @@ impl NfaBuilder {
 
 impl PartialOrd for State {
     fn partial_cmp(&self, other: &Self) -> Option<std::cmp::Ordering> {
-        self.id.partial_cmp(&other.id)
+        Some(self.cmp(other))
     }
 }
 
diff --git a/pango-parser/src/cfsm/dot.rs b/pango-parser/src/cfsm/dot.rs
index daaf3f6..00141b7 100644
--- a/pango-parser/src/cfsm/dot.rs
+++ b/pango-parser/src/cfsm/dot.rs
@@ -12,6 +12,8 @@ where
     /// dot language format.
     #[allow(unused)]
     pub fn to_dot(&self) -> String {
+        use std::fmt::Write;
+
         format!(
             "digraph cfsm {{\n\
                 \trankdir=LR;\n\
@@ -21,12 +23,14 @@ where
             \n\
                 {}\n\
             }}",
-            self.node_labels_dot()
-                .map(|l| format!("\t{}\n", l))
-                .collect::<String>(),
-            self.transitions_dot()
-                .map(|l| format!("\t{}\n", l))
-                .collect::<String>(),
+            self.node_labels_dot().fold(String::new(), |mut s, l| {
+                writeln!(s, "\t{}", l);
+                s
+            }),
+            self.transitions_dot().fold(String::new(), |mut s, l| {
+                writeln!(s, "\t{}", l);
+                s
+            })
         )
     }
 
diff --git a/pango-parser/src/cfsm/item.rs b/pango-parser/src/cfsm/item.rs
index 1e0d57b..b0ee2d1 100644
--- a/pango-parser/src/cfsm/item.rs
+++ b/pango-parser/src/cfsm/item.rs
@@ -148,11 +148,7 @@ where
                 .expect("variable should have an associated rule");
 
             for new_item_body in new_item_bodies {
-                if items
-                    .entry(head)
-                    .or_insert_with(ItemBodies::new)
-                    .insert(new_item_body)
-                {
+                if items.entry(head).or_default().insert(new_item_body) {
                     pending_bodies.push_back(new_item_body);
                 }
             }
diff --git a/pango-parser/src/grammar.rs b/pango-parser/src/grammar.rs
index 5f877a2..4855776 100644
--- a/pango-parser/src/grammar.rs
+++ b/pango-parser/src/grammar.rs
@@ -441,10 +441,7 @@ where
             Body::from([Symbol::Epsilon])
         };
 
-        self.rules
-            .entry(variable)
-            .or_insert_with(HashSet::new)
-            .insert(body)
+        self.rules.entry(variable).or_default().insert(body)
     }
 }
 
diff --git a/pango-parser/src/parser/table.rs b/pango-parser/src/parser/table.rs
index f7cd826..427c7b1 100644
--- a/pango-parser/src/parser/table.rs
+++ b/pango-parser/src/parser/table.rs
@@ -226,6 +226,7 @@ impl<T> From<crate::Terminal<&T>> for TableTerminal<T> {
     }
 }
 
+#[allow(clippy::from_over_into)]
 impl<'a, T> Into<crate::Terminal<&'a T>> for TableTerminal<T> {
     fn into(self) -> crate::Terminal<&'a T> {
         match self.0 {