diff --git a/actix-service/CHANGES.md b/actix-service/CHANGES.md
index 82481f46..971741e8 100644
--- a/actix-service/CHANGES.md
+++ b/actix-service/CHANGES.md
@@ -1,8 +1,14 @@
 # Changes
 
 ## Unreleased - 2020-xx-xx
+* `Service`, other traits, and many type signatures now take the the request type as a type
+  parameter instead of an associated type. [#232]
 * Upgrade `pin-project` to `1.0`.
 
+
+[#232]: https://github.com/actix/actix-net/pull/232
+
+
 ## 1.0.6 - 2020-08-09
 
 ### Fixed
diff --git a/actix-service/src/apply.rs b/actix-service/src/apply.rs
index 16d077ef..27a09684 100644
--- a/actix-service/src/apply.rs
+++ b/actix-service/src/apply.rs
@@ -12,12 +12,12 @@ use super::{IntoService, IntoServiceFactory, Service, ServiceFactory};
 /// Apply transform function to a service.
 ///
 /// The In and Out type params refer to the request and response types for the wrapped service.
-pub fn apply_fn<U, S, F, Fut, Req, In, Res, Err>(
-    service: U,
+pub fn apply_fn<I, S, F, Fut, Req, In, Res, Err>(
+    service: I,
     wrap_fn: F,
 ) -> Apply<S, F, Req, In, Res, Err>
 where
-    U: IntoService<S, In>,
+    I: IntoService<S, In>,
     S: Service<In, Error = Err>,
     F: FnMut(Req, &mut S) -> Fut,
     Fut: Future<Output = Result<Res, Err>>,
@@ -28,12 +28,12 @@ where
 /// Service factory that produces `apply_fn` service.
 ///
 /// The In and Out type params refer to the request and response types for the wrapped service.
-pub fn apply_fn_factory<U, SF, F, Fut, Req, In, Res, Err>(
-    service: U,
+pub fn apply_fn_factory<I, SF, F, Fut, Req, In, Res, Err>(
+    service: I,
     f: F,
 ) -> ApplyFactory<SF, F, Req, In, Res, Err>
 where
-    U: IntoServiceFactory<SF, In>,
+    I: IntoServiceFactory<SF, In>,
     SF: ServiceFactory<In, Error = Err>,
     F: FnMut(Req, &mut SF::Service) -> Fut + Clone,
     Fut: Future<Output = Result<Res, Err>>,
diff --git a/actix-service/src/apply_cfg.rs b/actix-service/src/apply_cfg.rs
index bb491485..da24e87d 100644
--- a/actix-service/src/apply_cfg.rs
+++ b/actix-service/src/apply_cfg.rs
@@ -7,150 +7,152 @@ use std::task::{Context, Poll};
 
 use crate::{Service, ServiceFactory};
 
-/// Convert `Fn(Config, &mut Service1) -> Future<Service2>` fn to a service factory
-pub fn apply_cfg<F, C, T, Req, R, S, E>(
-    srv: T,
+/// Convert `Fn(Config, &mut Service1) -> Future<Service2>` fn to a service factory.
+pub fn apply_cfg<S1, Req, F, Cfg, Fut, S2, Err>(
+    srv: S1,
     f: F,
 ) -> impl ServiceFactory<
     Req,
-    Config = C,
-    Response = S::Response,
-    Error = S::Error,
-    Service = S,
-    InitError = E,
-    Future = R,
+    Config = Cfg,
+    Response = S2::Response,
+    Error = S2::Error,
+    Service = S2,
+    InitError = Err,
+    Future = Fut,
 > + Clone
 where
-    F: FnMut(C, &mut T) -> R,
-    T: Service<Req>,
-    R: Future<Output = Result<S, E>>,
-    S: Service<Req>,
+    S1: Service<Req>,
+    F: FnMut(Cfg, &mut S1) -> Fut,
+    Fut: Future<Output = Result<S2, Err>>,
+    S2: Service<Req>,
 {
     ApplyConfigService {
         srv: Rc::new(RefCell::new((srv, f))),
-        _t: PhantomData,
+        _phantom: PhantomData,
     }
 }
 
-/// Convert `Fn(Config, &mut Service1) -> Future<Service2>` fn to a service factory
+/// Convert `Fn(Config, &mut ServiceFactory1) -> Future<ServiceFactory2>` fn to a service factory.
 ///
 /// Service1 get constructed from `T` factory.
-pub fn apply_cfg_factory<F, C, Req, T, R, S>(
-    factory: T,
+pub fn apply_cfg_factory<SF, Req, F, Cfg, Fut, S>(
+    factory: SF,
     f: F,
 ) -> impl ServiceFactory<
     Req,
-    Config = C,
+    Config = Cfg,
     Response = S::Response,
     Error = S::Error,
     Service = S,
-    InitError = T::InitError,
+    InitError = SF::InitError,
 > + Clone
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    T::InitError: From<T::Error>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    SF::InitError: From<SF::Error>,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
     ApplyConfigServiceFactory {
         srv: Rc::new(RefCell::new((factory, f))),
-        _t: PhantomData,
+        _phantom: PhantomData,
     }
 }
 
 /// Convert `Fn(Config, &mut Server) -> Future<Service>` fn to NewService\
-struct ApplyConfigService<F, C, Req, T, R, S, E>
+struct ApplyConfigService<S1, Req, F, Cfg, Fut, S2, Err>
 where
-    F: FnMut(C, &mut T) -> R,
-    T: Service<Req>,
-    R: Future<Output = Result<S, E>>,
-    S: Service<Req>,
+    S1: Service<Req>,
+    F: FnMut(Cfg, &mut S1) -> Fut,
+    Fut: Future<Output = Result<S2, Err>>,
+    S2: Service<Req>,
 {
-    srv: Rc<RefCell<(T, F)>>,
-    _t: PhantomData<(C, Req, R, S)>,
+    srv: Rc<RefCell<(S1, F)>>,
+    _phantom: PhantomData<(Cfg, Req, Fut, S2)>,
 }
 
-impl<F, C, Req, T, R, S, E> Clone for ApplyConfigService<F, C, Req, T, R, S, E>
+impl<S1, Req, F, Cfg, Fut, S2, Err> Clone for ApplyConfigService<S1, Req, F, Cfg, Fut, S2, Err>
 where
-    F: FnMut(C, &mut T) -> R,
-    T: Service<Req>,
-    R: Future<Output = Result<S, E>>,
-    S: Service<Req>,
+    S1: Service<Req>,
+    F: FnMut(Cfg, &mut S1) -> Fut,
+    Fut: Future<Output = Result<S2, Err>>,
+    S2: Service<Req>,
 {
     fn clone(&self) -> Self {
         ApplyConfigService {
             srv: self.srv.clone(),
-            _t: PhantomData,
+            _phantom: PhantomData,
         }
     }
 }
 
-impl<F, C, Req, T, R, S, E> ServiceFactory<Req> for ApplyConfigService<F, C, Req, T, R, S, E>
+impl<S1, Req, F, Cfg, Fut, S2, Err> ServiceFactory<Req>
+    for ApplyConfigService<S1, Req, F, Cfg, Fut, S2, Err>
 where
-    F: FnMut(C, &mut T) -> R,
-    T: Service<Req>,
-    R: Future<Output = Result<S, E>>,
-    S: Service<Req>,
+    S1: Service<Req>,
+    F: FnMut(Cfg, &mut S1) -> Fut,
+    Fut: Future<Output = Result<S2, Err>>,
+    S2: Service<Req>,
 {
-    type Config = C;
-    type Response = S::Response;
-    type Error = S::Error;
-    type Service = S;
+    type Config = Cfg;
+    type Response = S2::Response;
+    type Error = S2::Error;
+    type Service = S2;
 
-    type InitError = E;
-    type Future = R;
+    type InitError = Err;
+    type Future = Fut;
 
-    fn new_service(&self, cfg: C) -> Self::Future {
+    fn new_service(&self, cfg: Cfg) -> Self::Future {
         let (t, f) = &mut *self.srv.borrow_mut();
         f(cfg, t)
     }
 }
 
 /// Convert `Fn(&Config) -> Future<Service>` fn to NewService
-struct ApplyConfigServiceFactory<F, C, Req, T, R, S>
+struct ApplyConfigServiceFactory<SF, Req, F, Cfg, Fut, S>
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
-    srv: Rc<RefCell<(T, F)>>,
-    _t: PhantomData<(C, Req, R, S)>,
+    srv: Rc<RefCell<(SF, F)>>,
+    _phantom: PhantomData<(Cfg, Req, Fut, S)>,
 }
 
-impl<F, C, Req, T, R, S> Clone for ApplyConfigServiceFactory<F, C, Req, T, R, S>
+impl<SF, Req, F, Cfg, Fut, S> Clone for ApplyConfigServiceFactory<SF, Req, F, Cfg, Fut, S>
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
     fn clone(&self) -> Self {
         Self {
             srv: self.srv.clone(),
-            _t: PhantomData,
+            _phantom: PhantomData,
         }
     }
 }
 
-impl<F, C, Req, T, R, S> ServiceFactory<Req> for ApplyConfigServiceFactory<F, C, Req, T, R, S>
+impl<SF, Req, F, Cfg, Fut, S> ServiceFactory<Req>
+    for ApplyConfigServiceFactory<SF, Req, F, Cfg, Fut, S>
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    T::InitError: From<T::Error>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    SF::InitError: From<SF::Error>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
-    type Config = C;
+    type Config = Cfg;
     type Response = S::Response;
     type Error = S::Error;
     type Service = S;
 
-    type InitError = T::InitError;
-    type Future = ApplyConfigServiceFactoryResponse<F, C, Req, T, R, S>;
+    type InitError = SF::InitError;
+    type Future = ApplyConfigServiceFactoryResponse<SF, Req, F, Cfg, Fut, S>;
 
-    fn new_service(&self, cfg: C) -> Self::Future {
+    fn new_service(&self, cfg: Cfg) -> Self::Future {
         ApplyConfigServiceFactoryResponse {
             cfg: Some(cfg),
             store: self.srv.clone(),
@@ -160,42 +162,43 @@ where
 }
 
 #[pin_project::pin_project]
-struct ApplyConfigServiceFactoryResponse<F, C, Req, T, R, S>
+struct ApplyConfigServiceFactoryResponse<SF, Req, F, Cfg, Fut, S>
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    T::InitError: From<T::Error>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    SF::InitError: From<SF::Error>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
-    cfg: Option<C>,
-    store: Rc<RefCell<(T, F)>>,
+    cfg: Option<Cfg>,
+    store: Rc<RefCell<(SF, F)>>,
     #[pin]
-    state: State<T, R, S, Req>,
+    state: State<SF, Fut, S, Req>,
 }
 
 #[pin_project::pin_project(project = StateProj)]
-enum State<T, R, S, Req>
+enum State<SF, Fut, S, Req>
 where
-    T: ServiceFactory<Req, Config = ()>,
-    T::InitError: From<T::Error>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    SF::InitError: From<SF::Error>,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
-    A(#[pin] T::Future),
-    B(T::Service),
-    C(#[pin] R),
+    A(#[pin] SF::Future),
+    B(SF::Service),
+    C(#[pin] Fut),
 }
 
-impl<F, C, Req, T, R, S> Future for ApplyConfigServiceFactoryResponse<F, C, Req, T, R, S>
+impl<SF, Req, F, Cfg, Fut, S> Future
+    for ApplyConfigServiceFactoryResponse<SF, Req, F, Cfg, Fut, S>
 where
-    F: FnMut(C, &mut T::Service) -> R,
-    T: ServiceFactory<Req, Config = ()>,
-    T::InitError: From<T::Error>,
-    R: Future<Output = Result<S, T::InitError>>,
+    SF: ServiceFactory<Req, Config = ()>,
+    SF::InitError: From<SF::Error>,
+    F: FnMut(Cfg, &mut SF::Service) -> Fut,
+    Fut: Future<Output = Result<S, SF::InitError>>,
     S: Service<Req>,
 {
-    type Output = Result<S, T::InitError>;
+    type Output = Result<S, SF::InitError>;
 
     fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let mut this = self.as_mut().project();
diff --git a/actix-service/src/boxed.rs b/actix-service/src/boxed.rs
index baf84e79..31b90ca9 100644
--- a/actix-service/src/boxed.rs
+++ b/actix-service/src/boxed.rs
@@ -14,17 +14,17 @@ pub type BoxService<Req, Res, Err> =
 pub struct BoxServiceFactory<Cfg, Req, Res, Err, InitErr>(Inner<Cfg, Req, Res, Err, InitErr>);
 
 /// Create boxed service factory
-pub fn factory<T, Req>(
-    factory: T,
-) -> BoxServiceFactory<T::Config, Req, T::Response, T::Error, T::InitError>
+pub fn factory<SF, Req>(
+    factory: SF,
+) -> BoxServiceFactory<SF::Config, Req, SF::Response, SF::Error, SF::InitError>
 where
-    T: ServiceFactory<Req> + 'static,
+    SF: ServiceFactory<Req> + 'static,
     Req: 'static,
-    T::Response: 'static,
-    T::Service: 'static,
-    T::Future: 'static,
-    T::Error: 'static,
-    T::InitError: 'static,
+    SF::Response: 'static,
+    SF::Service: 'static,
+    SF::Future: 'static,
+    SF::Error: 'static,
+    SF::InitError: 'static,
 {
     BoxServiceFactory(Box::new(FactoryWrapper {
         factory,
@@ -75,33 +75,33 @@ where
     }
 }
 
-struct FactoryWrapper<C, T, Req>
+struct FactoryWrapper<SF, Req, C>
 where
-    T: ServiceFactory<Req>,
+    SF: ServiceFactory<Req>,
 {
-    factory: T,
+    factory: SF,
     _t: PhantomData<(C, Req)>,
 }
 
-impl<C, T, Req, Res, Err, InitErr> ServiceFactory<Req> for FactoryWrapper<C, T, Req>
+impl<SF, Req, Cfg, Res, Err, InitErr> ServiceFactory<Req> for FactoryWrapper<SF, Req, Cfg>
 where
     Req: 'static,
     Res: 'static,
     Err: 'static,
     InitErr: 'static,
-    T: ServiceFactory<Req, Config = C, Response = Res, Error = Err, InitError = InitErr>,
-    T::Future: 'static,
-    T::Service: 'static,
-    <T::Service as Service<Req>>::Future: 'static,
+    SF: ServiceFactory<Req, Config = Cfg, Response = Res, Error = Err, InitError = InitErr>,
+    SF::Future: 'static,
+    SF::Service: 'static,
+    <SF::Service as Service<Req>>::Future: 'static,
 {
     type Response = Res;
     type Error = Err;
     type InitError = InitErr;
-    type Config = C;
+    type Config = Cfg;
     type Service = BoxService<Req, Res, Err>;
     type Future = BoxFuture<Self::Service, Self::InitError>;
 
-    fn new_service(&self, cfg: C) -> Self::Future {
+    fn new_service(&self, cfg: Cfg) -> Self::Future {
         Box::pin(
             self.factory
                 .new_service(cfg)
@@ -123,10 +123,10 @@ where
     }
 }
 
-impl<T, Req, Res, Err> Service<Req> for ServiceWrapper<T, Req>
+impl<S, Req, Res, Err> Service<Req> for ServiceWrapper<S, Req>
 where
-    T: Service<Req, Response = Res, Error = Err>,
-    T::Future: 'static,
+    S: Service<Req, Response = Res, Error = Err>,
+    S::Future: 'static,
 {
     type Response = Res;
     type Error = Err;
diff --git a/actix-service/src/lib.rs b/actix-service/src/lib.rs
index 64d731ba..2dfa0dd7 100644
--- a/actix-service/src/lib.rs
+++ b/actix-service/src/lib.rs
@@ -338,10 +338,10 @@ where
     }
 }
 
-/// Convert object of type `T` to a service `S`
-pub fn into_service<U, S, Req>(tp: U) -> S
+/// Convert object of type `U` to a service `S`
+pub fn into_service<I, S, Req>(tp: I) -> S
 where
-    U: IntoService<S, Req>,
+    I: IntoService<S, Req>,
     S: Service<Req>,
 {
     tp.into_service()
diff --git a/actix-service/src/map_config.rs b/actix-service/src/map_config.rs
index d4382409..82b1789b 100644
--- a/actix-service/src/map_config.rs
+++ b/actix-service/src/map_config.rs
@@ -6,9 +6,9 @@ use super::{IntoServiceFactory, ServiceFactory};
 ///
 /// Note that this function consumes the receiving service factory and returns
 /// a wrapped version of it.
-pub fn map_config<U, SF, S, Req, F, Cfg>(factory: U, f: F) -> MapConfig<SF, Req, F, Cfg>
+pub fn map_config<I, SF, S, Req, F, Cfg>(factory: I, f: F) -> MapConfig<SF, Req, F, Cfg>
 where
-    U: IntoServiceFactory<SF, Req>,
+    I: IntoServiceFactory<SF, Req>,
     SF: ServiceFactory<Req>,
     F: Fn(Cfg) -> SF::Config,
 {
@@ -16,9 +16,9 @@ where
 }
 
 /// Replace config with unit.
-pub fn unit_config<U, SF, Cfg, Req>(factory: U) -> UnitConfig<SF, Cfg, Req>
+pub fn unit_config<I, SF, Cfg, Req>(factory: I) -> UnitConfig<SF, Cfg, Req>
 where
-    U: IntoServiceFactory<SF, Req>,
+    I: IntoServiceFactory<SF, Req>,
     SF: ServiceFactory<Req, Config = ()>,
 {
     UnitConfig::new(factory.into_factory())
diff --git a/actix-service/src/pipeline.rs b/actix-service/src/pipeline.rs
index fd615d36..cba7ce78 100644
--- a/actix-service/src/pipeline.rs
+++ b/actix-service/src/pipeline.rs
@@ -10,9 +10,9 @@ use crate::then::{ThenService, ThenServiceFactory};
 use crate::{IntoService, IntoServiceFactory, Service, ServiceFactory};
 
 /// Construct new pipeline with one service in pipeline chain.
-pub fn pipeline<U, S, Req>(service: U) -> Pipeline<S, Req>
+pub fn pipeline<I, S, Req>(service: I) -> Pipeline<S, Req>
 where
-    U: IntoService<S, Req>,
+    I: IntoService<S, Req>,
     S: Service<Req>,
 {
     Pipeline {
@@ -22,9 +22,9 @@ where
 }
 
 /// Construct new pipeline factory with one service factory.
-pub fn pipeline_factory<U, SF, Req>(factory: U) -> PipelineFactory<SF, Req>
+pub fn pipeline_factory<I, SF, Req>(factory: I) -> PipelineFactory<SF, Req>
 where
-    U: IntoServiceFactory<SF, Req>,
+    I: IntoServiceFactory<SF, Req>,
     SF: ServiceFactory<Req>,
 {
     PipelineFactory {
@@ -52,14 +52,14 @@ where
     ///
     /// Note that this function consumes the receiving service and returns a
     /// wrapped version of it.
-    pub fn and_then<F, U>(
+    pub fn and_then<I, S1>(
         self,
-        service: F,
-    ) -> Pipeline<impl Service<Req, Response = U::Response, Error = S::Error> + Clone, Req>
+        service: I,
+    ) -> Pipeline<impl Service<Req, Response = S1::Response, Error = S::Error> + Clone, Req>
     where
         Self: Sized,
-        F: IntoService<U, S::Response>,
-        U: Service<S::Response, Error = S::Error>,
+        I: IntoService<S1, S::Response>,
+        S1: Service<S::Response, Error = S::Error>,
     {
         Pipeline {
             service: AndThenService::new(self.service, service.into_service()),
@@ -70,14 +70,14 @@ where
     /// Apply function to specified service and use it as a next service in chain.
     ///
     /// Short version of `pipeline_factory(...).and_then(apply_fn(...))`
-    pub fn and_then_apply_fn<U, S1, F, Fut, In, Res, Err>(
+    pub fn and_then_apply_fn<I, S1, F, Fut, In, Res, Err>(
         self,
-        service: U,
+        service: I,
         wrap_fn: F,
     ) -> Pipeline<impl Service<Req, Response = Res, Error = Err> + Clone, Req>
     where
         Self: Sized,
-        U: IntoService<S1, In>,
+        I: IntoService<S1, In>,
         S1: Service<In>,
         F: FnMut(S::Response, &mut S1) -> Fut,
         Fut: Future<Output = Result<Res, Err>>,
@@ -94,14 +94,14 @@ where
     ///
     /// Note that this function consumes the receiving pipeline and returns a
     /// wrapped version of it.
-    pub fn then<F, U>(
+    pub fn then<F, S1>(
         self,
         service: F,
-    ) -> Pipeline<impl Service<Req, Response = U::Response, Error = S::Error> + Clone, Req>
+    ) -> Pipeline<impl Service<Req, Response = S1::Response, Error = S::Error> + Clone, Req>
     where
         Self: Sized,
-        F: IntoService<U, Result<S::Response, S::Error>>,
-        U: Service<Result<S::Response, S::Error>, Error = S::Error>,
+        F: IntoService<S1, Result<S::Response, S::Error>>,
+        S1: Service<Result<S::Response, S::Error>, Error = S::Error>,
     {
         Pipeline {
             service: ThenService::new(self.service, service.into_service()),
@@ -161,13 +161,13 @@ where
     }
 }
 
-impl<T: Service<Req>, Req> Service<Req> for Pipeline<T, Req> {
-    type Response = T::Response;
-    type Error = T::Error;
-    type Future = T::Future;
+impl<S: Service<Req>, Req> Service<Req> for Pipeline<S, Req> {
+    type Response = S::Response;
+    type Error = S::Error;
+    type Future = S::Future;
 
     #[inline]
-    fn poll_ready(&mut self, ctx: &mut Context<'_>) -> Poll<Result<(), T::Error>> {
+    fn poll_ready(&mut self, ctx: &mut Context<'_>) -> Poll<Result<(), S::Error>> {
         self.service.poll_ready(ctx)
     }
 
@@ -188,25 +188,25 @@ where
     SF: ServiceFactory<Req>,
 {
     /// Call another service after call to this one has resolved successfully.
-    pub fn and_then<F, U>(
+    pub fn and_then<I, SF1>(
         self,
-        factory: F,
+        factory: I,
     ) -> PipelineFactory<
         impl ServiceFactory<
                 Req,
-                Response = U::Response,
+                Response = SF1::Response,
                 Error = SF::Error,
                 Config = SF::Config,
                 InitError = SF::InitError,
-                Service = impl Service<Req, Response = U::Response, Error = SF::Error> + Clone,
+                Service = impl Service<Req, Response = SF1::Response, Error = SF::Error> + Clone,
             > + Clone,
         Req,
     >
     where
         Self: Sized,
         SF::Config: Clone,
-        F: IntoServiceFactory<U, SF::Response>,
-        U: ServiceFactory<
+        I: IntoServiceFactory<SF1, SF::Response>,
+        SF1: ServiceFactory<
             SF::Response,
             Config = SF::Config,
             Error = SF::Error,
@@ -222,9 +222,9 @@ where
     /// Apply function to specified service and use it as a next service in chain.
     ///
     /// Short version of `pipeline_factory(...).and_then(apply_fn_factory(...))`
-    pub fn and_then_apply_fn<U, SF1, Fut, F, In, Res, Err>(
+    pub fn and_then_apply_fn<I, SF1, Fut, F, In, Res, Err>(
         self,
-        factory: U,
+        factory: I,
         wrap_fn: F,
     ) -> PipelineFactory<
         impl ServiceFactory<
@@ -240,7 +240,7 @@ where
     where
         Self: Sized,
         SF::Config: Clone,
-        U: IntoServiceFactory<SF1, In>,
+        I: IntoServiceFactory<SF1, In>,
         SF1: ServiceFactory<In, Config = SF::Config, InitError = SF::InitError>,
         F: FnMut(SF::Response, &mut SF1::Service) -> Fut + Clone,
         Fut: Future<Output = Result<Res, Err>>,
@@ -258,25 +258,25 @@ where
     ///
     /// Note that this function consumes the receiving pipeline and returns a
     /// wrapped version of it.
-    pub fn then<F, U>(
+    pub fn then<I, SF1>(
         self,
-        factory: F,
+        factory: I,
     ) -> PipelineFactory<
         impl ServiceFactory<
                 Req,
-                Response = U::Response,
+                Response = SF1::Response,
                 Error = SF::Error,
                 Config = SF::Config,
                 InitError = SF::InitError,
-                Service = impl Service<Req, Response = U::Response, Error = SF::Error> + Clone,
+                Service = impl Service<Req, Response = SF1::Response, Error = SF::Error> + Clone,
             > + Clone,
         Req,
     >
     where
         Self: Sized,
         SF::Config: Clone,
-        F: IntoServiceFactory<U, Result<SF::Response, SF::Error>>,
-        U: ServiceFactory<
+        I: IntoServiceFactory<SF1, Result<SF::Response, SF::Error>>,
+        SF1: ServiceFactory<
             Result<SF::Response, SF::Error>,
             Config = SF::Config,
             Error = SF::Error,
@@ -342,16 +342,19 @@ where
     }
 }
 
-impl<T: ServiceFactory<Req>, Req> ServiceFactory<Req> for PipelineFactory<T, Req> {
-    type Config = T::Config;
-    type Response = T::Response;
-    type Error = T::Error;
-    type Service = T::Service;
-    type InitError = T::InitError;
-    type Future = T::Future;
+impl<SF, Req> ServiceFactory<Req> for PipelineFactory<SF, Req>
+where
+    SF: ServiceFactory<Req>,
+{
+    type Config = SF::Config;
+    type Response = SF::Response;
+    type Error = SF::Error;
+    type Service = SF::Service;
+    type InitError = SF::InitError;
+    type Future = SF::Future;
 
     #[inline]
-    fn new_service(&self, cfg: T::Config) -> Self::Future {
+    fn new_service(&self, cfg: SF::Config) -> Self::Future {
         self.factory.new_service(cfg)
     }
 }
diff --git a/actix-service/src/transform.rs b/actix-service/src/transform.rs
index 7f0634e7..d4d49417 100644
--- a/actix-service/src/transform.rs
+++ b/actix-service/src/transform.rs
@@ -8,11 +8,11 @@ use crate::transform_err::TransformMapInitErr;
 use crate::{IntoServiceFactory, Service, ServiceFactory};
 
 /// Apply transform to a service.
-pub fn apply<T, S, U, Req>(t: T, factory: U) -> ApplyTransform<T, S, Req>
+pub fn apply<T, S, I, Req>(t: T, factory: I) -> ApplyTransform<T, S, Req>
 where
+    I: IntoServiceFactory<S, Req>,
     S: ServiceFactory<Req>,
     T: Transform<S::Service, Req, InitError = S::InitError>,
-    U: IntoServiceFactory<S, Req>,
 {
     ApplyTransform::new(t, factory.into_factory())
 }
diff --git a/actix-tracing/src/lib.rs b/actix-tracing/src/lib.rs
index ada61daa..36aa21f2 100644
--- a/actix-tracing/src/lib.rs
+++ b/actix-tracing/src/lib.rs
@@ -103,14 +103,14 @@ where
 ///     |req: &Request| Some(span!(Level::INFO, "request", req.id))
 /// );
 /// ```
-pub fn trace<S, Req, U, F>(
-    service_factory: U,
+pub fn trace<S, Req, I, F>(
+    service_factory: I,
     make_span: F,
 ) -> ApplyTransform<TracingTransform<S::Service, S, F>, S, Req>
 where
+    I: IntoServiceFactory<S, Req>,
     S: ServiceFactory<Req>,
     F: Fn(&Req) -> Option<tracing::Span> + Clone,
-    U: IntoServiceFactory<S, Req>,
 {
     apply(
         TracingTransform::new(make_span),
diff --git a/actix-utils/src/timeout.rs b/actix-utils/src/timeout.rs
index d253d25d..17647206 100644
--- a/actix-utils/src/timeout.rs
+++ b/actix-utils/src/timeout.rs
@@ -165,21 +165,21 @@ where
 pin_project! {
     /// `TimeoutService` response future
     #[derive(Debug)]
-    pub struct TimeoutServiceResponse<T, Req>
+    pub struct TimeoutServiceResponse<S, Req>
     where
-        T: Service<Req>
+        S: Service<Req>
     {
         #[pin]
-        fut: T::Future,
+        fut: S::Future,
         sleep: Delay,
     }
 }
 
-impl<T, Req> Future for TimeoutServiceResponse<T, Req>
+impl<S, Req> Future for TimeoutServiceResponse<S, Req>
 where
-    T: Service<Req>,
+    S: Service<Req>,
 {
-    type Output = Result<T::Response, TimeoutError<T::Error>>;
+    type Output = Result<S::Response, TimeoutError<S::Error>>;
 
     fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
         let this = self.project();