diff --git a/packages/sycamore-core/src/hydrate.rs b/packages/sycamore-core/src/hydrate.rs
index 0de70d25..dadff49a 100644
--- a/packages/sycamore-core/src/hydrate.rs
+++ b/packages/sycamore-core/src/hydrate.rs
@@ -6,7 +6,7 @@
 use std::cell::RefCell;
 
 thread_local! {
-    static HYDRATION_CONTEXT: RefCell<Option<HydrationRegistry>> = RefCell::new(None);
+    static HYDRATION_CONTEXT: RefCell<Option<HydrationRegistry>> = const { RefCell::new(None) };
 }
 
 /// Run the closure inside a hydration context. If already inside a hydration context, creates a
diff --git a/packages/sycamore-reactive/src/iter.rs b/packages/sycamore-reactive/src/iter.rs
index 2739d9fa..fb30bcf2 100644
--- a/packages/sycamore-reactive/src/iter.rs
+++ b/packages/sycamore-reactive/src/iter.rs
@@ -19,9 +19,9 @@ use crate::*;
 /// * `key_fn` - A closure that returns an _unique_ key to each entry.
 ///
 ///  _Credits: Based on TypeScript implementation in <https://github.com/solidjs/solid>_
-pub fn map_keyed<T, K, U: 'static>(
-    list: impl Accessor<Vec<T>> + Clone + 'static,
-    map_fn: impl Fn(T) -> U + 'static,
+pub fn map_keyed<T, K, U>(
+    list: impl Accessor<Vec<T>> + 'static,
+    mut map_fn: impl FnMut(T) -> U + 'static,
     key_fn: impl Fn(&T) -> K + 'static,
 ) -> ReadSignal<Vec<U>>
 where
@@ -53,7 +53,7 @@ where
             disposers.reserve(new_items.len());
 
             for new_item in new_items.iter().cloned() {
-                let map_fn = &map_fn;
+                let map_fn = &mut map_fn;
                 let mapped = &mut mapped;
                 let new_disposer = create_child_scope(move || mapped.push(map_fn(new_item)));
                 disposers.push(Some(new_disposer));
@@ -97,7 +97,7 @@ where
                     "end and new_end are the last indexes where items[end - 1] != new_items[new_end - 1]"
                 );
 
-            // 0) Prepare a map of indices in newItems. Scan backwards so we encounter them in
+            // 0) Prepare a map of indices in new_items. Scan backwards so we encounter them in
             // natural order.
             let mut new_indices = HashMap::with_capacity(new_end - start);
 
@@ -106,20 +106,22 @@ where
             let mut new_indices_next = vec![None; new_end - start];
             for j in (start..new_end).rev() {
                 let item = &new_items[j];
-                let i = new_indices.get(&key_fn(item));
+                let key = key_fn(item);
+                let i = new_indices.get(&key);
                 new_indices_next[j - start] = i.copied();
-                new_indices.insert(key_fn(item), j);
+                new_indices.insert(key, j);
             }
 
             // 1) Step through old items and see if they can be found in new set; if so, mark
             // them as moved.
             for i in start..end {
                 let item = &items[i];
-                if let Some(j) = new_indices.get(&key_fn(item)).copied() {
+                let key = key_fn(item);
+                if let Some(j) = new_indices.get(&key).copied() {
                     // Moved. j is index of item in new_items.
                     mapped_tmp[j] = Some(mapped[i].clone());
                     disposers_tmp[j] = disposers[i].take();
-                    new_indices_next[j - start].and_then(|j| new_indices.insert(key_fn(item), j));
+                    new_indices_next[j - start].and_then(|j| new_indices.insert(key, j));
                 } else {
                     // Create new.
                     disposers[i].take().unwrap().dispose();
@@ -184,9 +186,9 @@ where
 /// * `list` - The list to be mapped. The list must be a [`ReadSignal`] (obtained from a [`Signal`])
 ///   and therefore reactive.
 /// * `map_fn` - A closure that maps from the input type to the output type.
-pub fn map_indexed<T, U: 'static>(
-    list: impl Accessor<Vec<T>> + Clone + 'static,
-    map_fn: impl Fn(T) -> U + 'static,
+pub fn map_indexed<T, U>(
+    list: impl Accessor<Vec<T>> + 'static,
+    mut map_fn: impl FnMut(T) -> U + 'static,
 ) -> ReadSignal<Vec<U>>
 where
     T: PartialEq + Clone + 'static,
diff --git a/packages/sycamore-reactive/src/root.rs b/packages/sycamore-reactive/src/root.rs
index 251473b3..cd8b8bc9 100644
--- a/packages/sycamore-reactive/src/root.rs
+++ b/packages/sycamore-reactive/src/root.rs
@@ -35,7 +35,7 @@ pub(crate) struct Root {
 
 thread_local! {
     /// The current reactive root.
-    static GLOBAL_ROOT: Cell<Option<&'static Root>> = Cell::new(None);
+    static GLOBAL_ROOT: Cell<Option<&'static Root>> = const { Cell::new(None) };
 }
 
 impl Root {
@@ -346,6 +346,7 @@ pub fn create_root(f: impl FnOnce()) -> RootHandle {
     {
         /// An unsafe wrapper around a raw pointer which we promise to never touch, effectively
         /// making it thread-safe.
+        #[allow(dead_code)]
         struct UnsafeSendPtr<T>(*const T);
         /// We never ever touch the pointer inside so surely this is safe!
         unsafe impl<T> Send for UnsafeSendPtr<T> {}
diff --git a/packages/sycamore-router/src/router.rs b/packages/sycamore-router/src/router.rs
index 1b8dcc1e..ccb1cb77 100644
--- a/packages/sycamore-router/src/router.rs
+++ b/packages/sycamore-router/src/router.rs
@@ -5,7 +5,6 @@ use std::rc::Rc;
 use sycamore::prelude::*;
 use sycamore::web::html::ev;
 use wasm_bindgen::prelude::*;
-use wasm_bindgen::JsCast;
 use web_sys::{Element, HtmlAnchorElement, HtmlBaseElement, KeyboardEvent};
 
 use crate::Route;
@@ -25,7 +24,7 @@ pub trait Integration {
 }
 
 thread_local! {
-    static PATHNAME: Cell<Option<Signal<String>>> = Cell::new(None);
+    static PATHNAME: Cell<Option<Signal<String>>> = const { Cell::new(None) };
 }
 
 /// A router integration that uses the
diff --git a/packages/sycamore-web/src/dom_node.rs b/packages/sycamore-web/src/dom_node.rs
index b93f972d..7ae647ad 100644
--- a/packages/sycamore-web/src/dom_node.rs
+++ b/packages/sycamore-web/src/dom_node.rs
@@ -12,8 +12,8 @@ use sycamore_core::generic_node::{
 use sycamore_core::render::insert;
 use sycamore_core::view::View;
 use sycamore_reactive::*;
+use wasm_bindgen::intern;
 use wasm_bindgen::prelude::*;
-use wasm_bindgen::{intern, JsCast};
 use web_sys::{Comment, Element, Node, Text};
 
 use crate::dom_node_template::{
@@ -23,13 +23,15 @@ use crate::{document, Html};
 
 #[wasm_bindgen]
 extern "C" {
+    /// Extend [`Node`] with an id field. This is used to make `Node` hashable.
     #[wasm_bindgen(extends = Node)]
     pub(super) type NodeWithId;
     #[wasm_bindgen(method, getter, js_name = "$$$nodeId")]
-    pub fn node_id(this: &NodeWithId) -> Option<usize>;
+    pub(crate) fn node_id(this: &NodeWithId) -> Option<usize>;
     #[wasm_bindgen(method, setter, js_name = "$$$nodeId")]
-    pub fn set_node_id(this: &NodeWithId, id: usize);
+    pub(crate) fn set_node_id(this: &NodeWithId, id: usize);
 
+    /// Extend [`Element`] with a failable `className` setter.
     #[wasm_bindgen(extends = Element)]
     type ElementTrySetClassName;
     #[wasm_bindgen(method, catch, setter, js_name = "className")]
@@ -42,7 +44,7 @@ pub(super) struct NodeId(pub usize);
 
 impl NodeId {
     pub fn new_with_node(node: &Node) -> Self {
-        thread_local!(static NODE_ID_COUNTER: Cell<usize> = Cell::new(1)); // 0 is reserved for default value.
+        thread_local!(static NODE_ID_COUNTER: Cell<usize> = const { Cell::new(1) }); // 0 is reserved for default value.
 
         let id = NODE_ID_COUNTER.with(|x| {
             let tmp = x.get();
diff --git a/packages/sycamore-web/src/hydrate_node.rs b/packages/sycamore-web/src/hydrate_node.rs
index 5923a1d7..6f2dd0e2 100644
--- a/packages/sycamore-web/src/hydrate_node.rs
+++ b/packages/sycamore-web/src/hydrate_node.rs
@@ -12,7 +12,6 @@ use sycamore_core::render::insert;
 use sycamore_core::view::View;
 use sycamore_reactive::*;
 use wasm_bindgen::prelude::*;
-use wasm_bindgen::JsCast;
 use web_sys::Node;
 
 use crate::dom_node::{DomNode, NodeId};
diff --git a/packages/sycamore-web/src/ssr_node.rs b/packages/sycamore-web/src/ssr_node.rs
index 6133a516..19f5d8ab 100644
--- a/packages/sycamore-web/src/ssr_node.rs
+++ b/packages/sycamore-web/src/ssr_node.rs
@@ -4,7 +4,6 @@ use std::borrow::Cow;
 use std::cell::RefCell;
 use std::collections::HashSet;
 use std::hash::{Hash, Hasher};
-use std::iter::FromIterator;
 use std::rc::{Rc, Weak};
 
 use indexmap::map::IndexMap;
diff --git a/packages/sycamore/src/builder.rs b/packages/sycamore/src/builder.rs
index 64f4cf5d..96fc8222 100644
--- a/packages/sycamore/src/builder.rs
+++ b/packages/sycamore/src/builder.rs
@@ -4,7 +4,6 @@
 //! HTML.
 
 use std::borrow::Cow;
-use std::iter::FromIterator;
 use std::rc::Rc;
 
 use sycamore_core::event::{EventDescriptor, EventHandler};
diff --git a/packages/sycamore/src/utils.rs b/packages/sycamore/src/utils.rs
index 234d4f7b..db139ac4 100644
--- a/packages/sycamore/src/utils.rs
+++ b/packages/sycamore/src/utils.rs
@@ -18,7 +18,6 @@ use sycamore_core::event::{EventDescriptor, EventHandler};
 pub use sycamore_core::render;
 use wasm_bindgen::JsValue;
 
-use crate::generic_node::GenericNode;
 use crate::prelude::*;
 use crate::rt::Event;
 use crate::web::html::ev;
diff --git a/packages/sycamore/src/web/portal.rs b/packages/sycamore/src/web/portal.rs
index 2e3de38e..d1755d27 100644
--- a/packages/sycamore/src/web/portal.rs
+++ b/packages/sycamore/src/web/portal.rs
@@ -4,7 +4,6 @@ use std::any::Any;
 
 use wasm_bindgen::prelude::*;
 
-use crate::component::Children;
 use crate::prelude::*;
 
 /// Props for [`Portal`].