diff --git a/crates/flycheck/src/lib.rs b/crates/flycheck/src/lib.rs
index accb14a51de..7e78178dde2 100644
--- a/crates/flycheck/src/lib.rs
+++ b/crates/flycheck/src/lib.rs
@@ -485,7 +485,7 @@ impl CargoActor {
 
             error.push_str(line);
             error.push('\n');
-            return false;
+            false
         };
         let output = streaming_output(
             self.stdout,
diff --git a/crates/hir-def/src/body/pretty.rs b/crates/hir-def/src/body/pretty.rs
index 318f654c16f..bdc84fefe66 100644
--- a/crates/hir-def/src/body/pretty.rs
+++ b/crates/hir-def/src/body/pretty.rs
@@ -35,11 +35,10 @@ pub(super) fn print_body_hir(db: &dyn DefDatabase, body: &Body, owner: DefWithBo
         DefWithBodyId::VariantId(it) => {
             let src = it.parent.child_source(db);
             let variant = &src.value[it.local_id];
-            let name = match &variant.name() {
+            match &variant.name() {
                 Some(name) => name.to_string(),
                 None => "_".to_string(),
-            };
-            format!("{name}")
+            }
         }
     };
 
@@ -456,7 +455,7 @@ impl<'a> Printer<'a> {
     fn print_block(
         &mut self,
         label: Option<&str>,
-        statements: &Box<[Statement]>,
+        statements: &[Statement],
         tail: &Option<la_arena::Idx<Expr>>,
     ) {
         self.whitespace();
@@ -466,7 +465,7 @@ impl<'a> Printer<'a> {
         w!(self, "{{");
         if !statements.is_empty() || tail.is_some() {
             self.indented(|p| {
-                for stmt in &**statements {
+                for stmt in statements {
                     p.print_stmt(stmt);
                 }
                 if let Some(tail) = tail {
diff --git a/crates/parser/src/grammar/expressions.rs b/crates/parser/src/grammar/expressions.rs
index a884d8b6ec8..e6fb9e9d335 100644
--- a/crates/parser/src/grammar/expressions.rs
+++ b/crates/parser/src/grammar/expressions.rs
@@ -417,7 +417,7 @@ fn postfix_expr(
         allow_calls = true;
         block_like = BlockLike::NotBlock;
     }
-    return (lhs, block_like);
+    (lhs, block_like)
 }
 
 fn postfix_dot_expr<const FLOAT_RECOVERY: bool>(
diff --git a/crates/parser/src/grammar/items.rs b/crates/parser/src/grammar/items.rs
index 5e0951bf8b5..1c056819f4b 100644
--- a/crates/parser/src/grammar/items.rs
+++ b/crates/parser/src/grammar/items.rs
@@ -19,7 +19,7 @@ use super::*;
 // struct S;
 pub(super) fn mod_contents(p: &mut Parser<'_>, stop_on_r_curly: bool) {
     attributes::inner_attrs(p);
-    while !p.at(EOF) && !(p.at(T!['}']) && stop_on_r_curly) {
+    while !(p.at(EOF) || (p.at(T!['}']) && stop_on_r_curly)) {
         item_or_macro(p, stop_on_r_curly);
     }
 }
diff --git a/crates/parser/src/parser.rs b/crates/parser/src/parser.rs
index 280416ae7c9..ef413c63754 100644
--- a/crates/parser/src/parser.rs
+++ b/crates/parser/src/parser.rs
@@ -205,7 +205,7 @@ impl<'t> Parser<'t> {
             marker.bomb.defuse();
             marker = new_marker;
         };
-        self.pos += 1 as usize;
+        self.pos += 1;
         self.push_event(Event::FloatSplitHack { ends_in_dot });
         (ends_in_dot, marker)
     }
diff --git a/crates/parser/src/shortcuts.rs b/crates/parser/src/shortcuts.rs
index 47e4adcbbe6..5cdb39700dd 100644
--- a/crates/parser/src/shortcuts.rs
+++ b/crates/parser/src/shortcuts.rs
@@ -46,10 +46,8 @@ impl<'a> LexedStr<'a> {
                     // Tag the token as joint if it is float with a fractional part
                     // we use this jointness to inform the parser about what token split
                     // event to emit when we encounter a float literal in a field access
-                    if kind == SyntaxKind::FLOAT_NUMBER {
-                        if !self.text(i).ends_with('.') {
-                            res.was_joint();
-                        }
+                    if kind == SyntaxKind::FLOAT_NUMBER && !self.text(i).ends_with('.') {
+                        res.was_joint();
                     }
                 }
 
diff --git a/crates/syntax/src/ast/expr_ext.rs b/crates/syntax/src/ast/expr_ext.rs
index 1eef2861165..36980b146ef 100644
--- a/crates/syntax/src/ast/expr_ext.rs
+++ b/crates/syntax/src/ast/expr_ext.rs
@@ -370,8 +370,7 @@ impl ast::BlockExpr {
         match parent.kind() {
             FOR_EXPR | IF_EXPR => parent
                 .children()
-                .filter(|it| ast::Expr::can_cast(it.kind()))
-                .next()
+                .find(|it| ast::Expr::can_cast(it.kind()))
                 .map_or(true, |it| it == *self.syntax()),
             LET_ELSE | FN | WHILE_EXPR | LOOP_EXPR | CONST_BLOCK_PAT => false,
             _ => true,
diff --git a/crates/syntax/src/ast/make.rs b/crates/syntax/src/ast/make.rs
index cc0d7f4b48e..8d2dc8709ba 100644
--- a/crates/syntax/src/ast/make.rs
+++ b/crates/syntax/src/ast/make.rs
@@ -195,7 +195,7 @@ pub fn ty_alias(
         }
     }
 
-    s.push_str(";");
+    s.push(';');
     ast_from_text(&s)
 }
 
@@ -399,7 +399,7 @@ pub fn hacky_block_expr(
                     format_to!(buf, "    {t}\n")
                 } else if kind == SyntaxKind::WHITESPACE {
                     let content = t.text().trim_matches(|c| c != '\n');
-                    if content.len() >= 1 {
+                    if !content.is_empty() {
                         format_to!(buf, "{}", &content[1..])
                     }
                 }
diff --git a/crates/vfs/src/lib.rs b/crates/vfs/src/lib.rs
index ff8a2b96733..fe3dfe61968 100644
--- a/crates/vfs/src/lib.rs
+++ b/crates/vfs/src/lib.rs
@@ -109,13 +109,6 @@ pub enum ChangeKind {
 }
 
 impl Vfs {
-    /// Amount of files currently stored.
-    ///
-    /// Note that this includes deleted files.
-    pub fn len(&self) -> usize {
-        self.data.len()
-    }
-
     /// Id of the given path if it exists in the `Vfs` and is not deleted.
     pub fn file_id(&self, path: &VfsPath) -> Option<FileId> {
         self.interner.get(path).filter(|&it| self.get(it).is_some())
diff --git a/lib/la-arena/src/map.rs b/lib/la-arena/src/map.rs
index 610f7d92d65..750f345b539 100644
--- a/lib/la-arena/src/map.rs
+++ b/lib/la-arena/src/map.rs
@@ -1,3 +1,4 @@
+use std::iter::Enumerate;
 use std::marker::PhantomData;
 
 use crate::Idx;
@@ -94,12 +95,6 @@ impl<T, V> ArenaMap<Idx<T>, V> {
             .filter_map(|(idx, o)| Some((Self::from_idx(idx), o.as_mut()?)))
     }
 
-    /// Returns an iterator over the arena indexes and values in the map.
-    // FIXME: Implement `IntoIterator` trait.
-    pub fn into_iter(self) -> impl Iterator<Item = (Idx<T>, V)> + DoubleEndedIterator {
-        self.v.into_iter().enumerate().filter_map(|(idx, o)| Some((Self::from_idx(idx), o?)))
-    }
-
     /// Gets the given key's corresponding entry in the map for in-place manipulation.
     pub fn entry(&mut self, idx: Idx<T>) -> Entry<'_, Idx<T>, V> {
         let idx = Self::to_idx(idx);
@@ -154,6 +149,63 @@ impl<T, V> FromIterator<(Idx<V>, T)> for ArenaMap<Idx<V>, T> {
     }
 }
 
+pub struct ArenaMapIter<IDX, V> {
+    iter: Enumerate<std::vec::IntoIter<Option<V>>>,
+    _ty: PhantomData<IDX>,
+}
+
+impl<T, V> IntoIterator for ArenaMap<Idx<T>, V> {
+    type Item = (Idx<T>, V);
+
+    type IntoIter = ArenaMapIter<Idx<T>, V>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        let iter = self.v.into_iter().enumerate();
+        Self::IntoIter { iter, _ty: PhantomData }
+    }
+}
+
+impl<T, V> ArenaMapIter<Idx<T>, V> {
+    fn mapper((idx, o): (usize, Option<V>)) -> Option<(Idx<T>, V)> {
+        Some((ArenaMap::<Idx<T>, V>::from_idx(idx), o?))
+    }
+}
+
+impl<T, V> Iterator for ArenaMapIter<Idx<T>, V> {
+    type Item = (Idx<T>, V);
+
+    #[inline]
+    fn next(&mut self) -> Option<Self::Item> {
+        for next in self.iter.by_ref() {
+            match Self::mapper(next) {
+                Some(r) => return Some(r),
+                None => continue,
+            }
+        }
+
+        None
+    }
+
+    #[inline]
+    fn size_hint(&self) -> (usize, Option<usize>) {
+        self.iter.size_hint()
+    }
+}
+
+impl<T, V> DoubleEndedIterator for ArenaMapIter<Idx<T>, V> {
+    #[inline]
+    fn next_back(&mut self) -> Option<Self::Item> {
+        while let Some(next_back) = self.iter.next_back() {
+            match Self::mapper(next_back) {
+                Some(r) => return Some(r),
+                None => continue,
+            }
+        }
+
+        None
+    }
+}
+
 /// A view into a single entry in a map, which may either be vacant or occupied.
 ///
 /// This `enum` is constructed from the [`entry`] method on [`ArenaMap`].