diff --git a/examples/error-handle/src/main.rs b/examples/error-handle/src/main.rs
index beb11e9c..38793b71 100644
--- a/examples/error-handle/src/main.rs
+++ b/examples/error-handle/src/main.rs
@@ -1,3 +1,5 @@
+#![feature(trait_upcasting)]
+
 //! example of error handling in xitca-web.
 //! code must be compiled with nightly Rust.
 
diff --git a/http/src/h2/proto/headers.rs b/http/src/h2/proto/headers.rs
index 257c96ae..e2b72a56 100644
--- a/http/src/h2/proto/headers.rs
+++ b/http/src/h2/proto/headers.rs
@@ -550,7 +550,7 @@ where
                         }
                     }
                 }
-                header => self.pseudo.from_header(
+                header => self.pseudo.parse(
                     header,
                     max_header_list_size,
                     &mut self.is_over_size,
@@ -606,7 +606,7 @@ where
 pub trait _Pseudo {
     fn into_iter(self) -> impl Iterator<Item = super::hpack::Header<Option<HeaderName>>> + Send;
 
-    fn from_header(
+    fn parse(
         &mut self,
         header: super::hpack::Header,
         max_header_list_size: usize,
@@ -660,7 +660,7 @@ impl _Pseudo for Pseudo {
         Iter(self)
     }
 
-    fn from_header(
+    fn parse(
         &mut self,
         header: super::hpack::Header,
         max_header_list_size: usize,
@@ -728,7 +728,7 @@ impl _Pseudo for ResponsePseudo {
         core::iter::once_with(move || super::hpack::Header::Status(self.status))
     }
 
-    fn from_header(
+    fn parse(
         &mut self,
         header: super::hpack::Header,
         max_header_list_size: usize,
@@ -767,7 +767,7 @@ impl _Pseudo for () {
         core::iter::empty()
     }
 
-    fn from_header(&mut self, _: super::hpack::Header, _: usize, _: &mut bool, _: bool, _: &mut bool, _: &mut usize) {}
+    fn parse(&mut self, _: super::hpack::Header, _: usize, _: &mut bool, _: bool, _: &mut bool, _: &mut usize) {}
 
     fn as_header_size(&self) -> usize {
         0
diff --git a/web/CHANGES.md b/web/CHANGES.md
index 43fc37a9..e2dd29d3 100644
--- a/web/CHANGES.md
+++ b/web/CHANGES.md
@@ -1,4 +1,6 @@
 # unreleased
+## Add
+- `StateRef` can used for extracting `?Sized` type from application state.
 
 # 0.2.1
 ## Add
diff --git a/web/Cargo.toml b/web/Cargo.toml
index d17700d1..81050972 100644
--- a/web/Cargo.toml
+++ b/web/Cargo.toml
@@ -1,6 +1,6 @@
 [package]
 name = "xitca-web"
-version = "0.2.1"
+version = "0.2.2"
 edition = "2021"
 license = "Apache-2.0"
 description = "an async web framework"
diff --git a/web/src/error.rs b/web/src/error.rs
index 8324dd84..5ab08127 100644
--- a/web/src/error.rs
+++ b/web/src/error.rs
@@ -144,7 +144,9 @@ use self::service_impl::ErrorService;
 ///     assert_eq!(res.status().as_u16(), 200);
 ///
 ///     // upcast and downcast to concrete error type again.
-///     // *. trait upcast is a feature stabled in Rust 1.76
+///     // *. trait upcast is a nightly feature.
+///     // see https://github.com/rust-lang/rust/issues/65991 for detail
+///     
 ///     // let e = &*e as &dyn error::Error;
 ///     // assert!(e.downcast_ref::<Foo>().is_some());
 /// }
diff --git a/web/src/handler/types/state.rs b/web/src/handler/types/state.rs
index 27da954f..c87f411a 100644
--- a/web/src/handler/types/state.rs
+++ b/web/src/handler/types/state.rs
@@ -6,7 +6,9 @@ use crate::{body::BodyStream, context::WebContext, error::Error, handler::FromRe
 
 /// App state extractor.
 /// S type must be the same with the type passed to App::with_xxx_state(S).
-pub struct StateRef<'a, S>(pub &'a S);
+pub struct StateRef<'a, S>(pub &'a S)
+where
+    S: ?Sized;
 
 impl<S: fmt::Debug> fmt::Debug for StateRef<'_, S> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
@@ -32,7 +34,7 @@ impl<'a, 'r, C, B, T> FromRequest<'a, WebContext<'r, C, B>> for StateRef<'a, T>
 where
     C: Borrow<T>,
     B: BodyStream,
-    T: 'static,
+    T: ?Sized + 'static,
 {
     type Type<'b> = StateRef<'b, T>;
     type Error = Error<C>;