diff --git a/packages/generational-box/src/lib.rs b/packages/generational-box/src/lib.rs
index b8fdee94b..4bbe06d8a 100644
--- a/packages/generational-box/src/lib.rs
+++ b/packages/generational-box/src/lib.rs
@@ -322,30 +322,30 @@ impl<T, S> Clone for GenerationalBox<T, S> {
 }
 
 /// A trait for types that can be mapped.
-pub trait Mappable<T>: Deref<Target = T> {
+pub trait Mappable<T: ?Sized>: Deref<Target = T> {
     /// The type after the mapping.
-    type Mapped<U: 'static>: Mappable<U> + Deref<Target = U>;
+    type Mapped<U: ?Sized + 'static>: Mappable<U> + Deref<Target = U>;
 
     /// Map the value.
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U>;
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U>;
 
     /// Try to map the value.
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&T) -> Option<&U>,
     ) -> Option<Self::Mapped<U>>;
 }
 
 /// A trait for types that can be mapped mutably.
-pub trait MappableMut<T>: DerefMut<Target = T> {
+pub trait MappableMut<T: ?Sized>: DerefMut<Target = T> {
     /// The type after the mapping.
-    type Mapped<U: 'static>: MappableMut<U> + DerefMut<Target = U>;
+    type Mapped<U: ?Sized + 'static>: MappableMut<U> + DerefMut<Target = U>;
 
     /// Map the value.
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U>;
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U>;
 
     /// Try to map the value.
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&mut T) -> Option<&mut U>,
     ) -> Option<Self::Mapped<U>>;
diff --git a/packages/generational-box/src/references.rs b/packages/generational-box/src/references.rs
index c2f52946c..115babf7a 100644
--- a/packages/generational-box/src/references.rs
+++ b/packages/generational-box/src/references.rs
@@ -1,4 +1,5 @@
 use std::{
+    fmt::{Debug, Display},
     marker::PhantomData,
     ops::{Deref, DerefMut},
 };
@@ -6,7 +7,7 @@ use std::{
 use crate::{Mappable, MappableMut};
 
 /// A reference to a value in a generational box.
-pub struct GenerationalRef<T: 'static, R: Mappable<T>> {
+pub struct GenerationalRef<T: ?Sized + 'static, R: Mappable<T>> {
     inner: R,
     phantom: PhantomData<T>,
     #[cfg(any(debug_assertions, feature = "debug_borrows"))]
@@ -27,10 +28,10 @@ impl<T: 'static, R: Mappable<T>> GenerationalRef<T, R> {
     }
 }
 
-impl<T: 'static, R: Mappable<T>> Mappable<T> for GenerationalRef<T, R> {
-    type Mapped<U: 'static> = GenerationalRef<U, R::Mapped<U>>;
+impl<T: ?Sized + 'static, R: Mappable<T>> Mappable<T> for GenerationalRef<T, R> {
+    type Mapped<U: ?Sized + 'static> = GenerationalRef<U, R::Mapped<U>>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
         GenerationalRef {
             inner: R::map(_self.inner, f),
             phantom: PhantomData,
@@ -42,7 +43,7 @@ impl<T: 'static, R: Mappable<T>> Mappable<T> for GenerationalRef<T, R> {
         }
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&T) -> Option<&U>,
     ) -> Option<Self::Mapped<U>> {
@@ -64,7 +65,19 @@ impl<T: 'static, R: Mappable<T>> Mappable<T> for GenerationalRef<T, R> {
     }
 }
 
-impl<T: 'static, R: Mappable<T>> Deref for GenerationalRef<T, R> {
+impl<T: ?Sized + Debug, R: Mappable<T>> Debug for GenerationalRef<T, R> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.inner.deref().fmt(f)
+    }
+}
+
+impl<T: ?Sized + Display, R: Mappable<T>> Display for GenerationalRef<T, R> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        self.inner.deref().fmt(f)
+    }
+}
+
+impl<T: ?Sized + 'static, R: Mappable<T>> Deref for GenerationalRef<T, R> {
     type Target = T;
 
     fn deref(&self) -> &Self::Target {
@@ -90,7 +103,7 @@ impl Drop for GenerationalRefBorrowInfo {
 }
 
 /// A mutable reference to a value in a generational box.
-pub struct GenerationalRefMut<T: 'static, W: MappableMut<T>> {
+pub struct GenerationalRefMut<T: ?Sized + 'static, W: MappableMut<T>> {
     inner: W,
     phantom: PhantomData<T>,
     #[cfg(any(debug_assertions, feature = "debug_borrows"))]
@@ -112,10 +125,10 @@ impl<T: 'static, R: MappableMut<T>> GenerationalRefMut<T, R> {
     }
 }
 
-impl<T: 'static, W: MappableMut<T>> MappableMut<T> for GenerationalRefMut<T, W> {
-    type Mapped<U: 'static> = GenerationalRefMut<U, W::Mapped<U>>;
+impl<T: ?Sized + 'static, W: MappableMut<T>> MappableMut<T> for GenerationalRefMut<T, W> {
+    type Mapped<U: ?Sized + 'static> = GenerationalRefMut<U, W::Mapped<U>>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
         GenerationalRefMut {
             inner: W::map(_self.inner, f),
             phantom: PhantomData,
@@ -124,7 +137,7 @@ impl<T: 'static, W: MappableMut<T>> MappableMut<T> for GenerationalRefMut<T, W>
         }
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&mut T) -> Option<&mut U>,
     ) -> Option<Self::Mapped<U>> {
@@ -143,7 +156,7 @@ impl<T: 'static, W: MappableMut<T>> MappableMut<T> for GenerationalRefMut<T, W>
     }
 }
 
-impl<T: 'static, W: MappableMut<T>> Deref for GenerationalRefMut<T, W> {
+impl<T: ?Sized + 'static, W: MappableMut<T>> Deref for GenerationalRefMut<T, W> {
     type Target = T;
 
     fn deref(&self) -> &Self::Target {
@@ -151,7 +164,7 @@ impl<T: 'static, W: MappableMut<T>> Deref for GenerationalRefMut<T, W> {
     }
 }
 
-impl<T: 'static, W: MappableMut<T>> DerefMut for GenerationalRefMut<T, W> {
+impl<T: ?Sized + 'static, W: MappableMut<T>> DerefMut for GenerationalRefMut<T, W> {
     fn deref_mut(&mut self) -> &mut Self::Target {
         self.inner.deref_mut()
     }
diff --git a/packages/generational-box/src/sync.rs b/packages/generational-box/src/sync.rs
index e11c17418..7d940278f 100644
--- a/packages/generational-box/src/sync.rs
+++ b/packages/generational-box/src/sync.rs
@@ -48,14 +48,14 @@ impl AnyStorage for SyncStorage {
     }
 }
 
-impl<T> Mappable<T> for MappedRwLockReadGuard<'static, T> {
-    type Mapped<U: 'static> = MappedRwLockReadGuard<'static, U>;
+impl<T: ?Sized> Mappable<T> for MappedRwLockReadGuard<'static, T> {
+    type Mapped<U: ?Sized + 'static> = MappedRwLockReadGuard<'static, U>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
         MappedRwLockReadGuard::map(_self, f)
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&T) -> Option<&U>,
     ) -> Option<Self::Mapped<U>> {
@@ -63,14 +63,14 @@ impl<T> Mappable<T> for MappedRwLockReadGuard<'static, T> {
     }
 }
 
-impl<T> MappableMut<T> for MappedRwLockWriteGuard<'static, T> {
-    type Mapped<U: 'static> = MappedRwLockWriteGuard<'static, U>;
+impl<T: ?Sized> MappableMut<T> for MappedRwLockWriteGuard<'static, T> {
+    type Mapped<U: ?Sized + 'static> = MappedRwLockWriteGuard<'static, U>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
         MappedRwLockWriteGuard::map(_self, f)
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&mut T) -> Option<&mut U>,
     ) -> Option<Self::Mapped<U>> {
diff --git a/packages/generational-box/src/unsync.rs b/packages/generational-box/src/unsync.rs
index dac9967f0..d941dd00b 100644
--- a/packages/generational-box/src/unsync.rs
+++ b/packages/generational-box/src/unsync.rs
@@ -13,14 +13,14 @@ impl Default for UnsyncStorage {
     }
 }
 
-impl<T> Mappable<T> for Ref<'static, T> {
-    type Mapped<U: 'static> = Ref<'static, U>;
+impl<T: ?Sized> Mappable<T> for Ref<'static, T> {
+    type Mapped<U: ?Sized + 'static> = Ref<'static, U>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&T) -> &U) -> Self::Mapped<U> {
         Ref::map(_self, f)
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&T) -> Option<&U>,
     ) -> Option<Self::Mapped<U>> {
@@ -28,14 +28,14 @@ impl<T> Mappable<T> for Ref<'static, T> {
     }
 }
 
-impl<T> MappableMut<T> for RefMut<'static, T> {
-    type Mapped<U: 'static> = RefMut<'static, U>;
+impl<T: ?Sized> MappableMut<T> for RefMut<'static, T> {
+    type Mapped<U: ?Sized + 'static> = RefMut<'static, U>;
 
-    fn map<U: 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
+    fn map<U: ?Sized + 'static>(_self: Self, f: impl FnOnce(&mut T) -> &mut U) -> Self::Mapped<U> {
         RefMut::map(_self, f)
     }
 
-    fn try_map<U: 'static>(
+    fn try_map<U: ?Sized + 'static>(
         _self: Self,
         f: impl FnOnce(&mut T) -> Option<&mut U>,
     ) -> Option<Self::Mapped<U>> {
diff --git a/packages/signals/src/map.rs b/packages/signals/src/map.rs
index 6c02b8553..b7093e27b 100644
--- a/packages/signals/src/map.rs
+++ b/packages/signals/src/map.rs
@@ -15,7 +15,7 @@ pub struct MappedSignal<U: 'static + ?Sized> {
 
 impl MappedSignal<()> {
     /// Create a new mapped signal.
-    pub fn new<T, S: Storage<SignalData<T>>, U>(
+    pub fn new<T, S: Storage<SignalData<T>>, U: ?Sized>(
         signal: Signal<T, S>,
         mapping: impl Fn(&T) -> &U + 'static,
     ) -> MappedSignal<
diff --git a/packages/signals/tests/map.rs b/packages/signals/tests/map.rs
index e93d2fed0..bea13009a 100644
--- a/packages/signals/tests/map.rs
+++ b/packages/signals/tests/map.rs
@@ -18,10 +18,7 @@ fn create_signals_global() {
         let signal = create_without_cx();
         let mapped = MappedSignal::new(signal, |v| v.as_bytes());
 
-        render! {
-            "{signal:?}"
-            "{mapped:?}"
-        }
+        render! { "{signal:?}", "{mapped:?}" }
     }
 
     let _edits = dom.rebuild().santize();