feat: apply suggestions from code review

libs/@local/graph/api/src/rpc/account.rs

@@ -53,6 +53,7 @@ impl Error for AccountNotFoundError {
     }
 }
 
+#[must_use]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, derive_more::Display, derive_more::Error)]
 #[display("unable to fullfil account request")]
 pub struct AccountError;
@@ -469,6 +470,7 @@ pub struct AccountDelegate<T> {
 }
 
 impl<T> AccountDelegate<T> {
+    #[must_use]
     pub const fn new(inner: T) -> Self {
         Self { inner }
     }

libs/@local/graph/api/src/rpc/auth.rs

@@ -15,6 +15,7 @@ use hash_graph_types::account::AccountId;
 
 use super::session::Account;
 
+#[must_use]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, derive_more::Display, derive_more::Error)]
 #[display("unable to authenticate user")]
 pub struct AuthenticationError;
@@ -115,6 +116,13 @@ pub struct AuthenticationDelegate<T> {
     inner: T,
 }
 
+impl<T> AuthenticationDelegate<T> {
+    #[must_use]
+    pub const fn new(inner: T) -> Self {
+        Self { inner }
+    }
+}
+
 impl<T, C> SubsystemDelegate<C> for AuthenticationDelegate<T>
 where
     T: AuthenticationSystem<authenticate(..): Send, ExecutionScope: Send> + Send,
@@ -160,7 +168,7 @@ pub struct AuthenticationClient<S, C> {
 
 impl<S, C> AuthenticationClient<S, C> {
     #[must_use]
-    pub fn new() -> Self {
+    pub const fn new() -> Self {
         Self {
             _service: PhantomData,
             _codec: PhantomData,

libs/@local/graph/api/src/rpc/echo.rs

@@ -14,6 +14,7 @@ use harpc_types::response_kind::ResponseKind;
 
 use super::session::Account;
 
+#[must_use]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, derive_more::Display, derive_more::Error)]
 #[display("unable to fullfil ping request")]
 pub struct EchoError;
@@ -108,6 +109,7 @@ pub struct EchoDelegate<T> {
 }
 
 impl<T> EchoDelegate<T> {
+    #[must_use]
     pub const fn new(inner: T) -> Self {
         Self { inner }
     }
@@ -155,6 +157,22 @@ pub struct EchoClient<S, C> {
     _codec: PhantomData<fn() -> *const C>,
 }
 
+impl<S, C> EchoClient<S, C> {
+    #[must_use]
+    pub const fn new() -> Self {
+        Self {
+            _service: PhantomData,
+            _codec: PhantomData,
+        }
+    }
+}
+
+impl<S, C> Default for EchoClient<S, C> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<S, C> EchoSystem for EchoClient<S, C>
 where
     S: harpc_client::connection::ConnectionService<C>,

libs/@local/harpc/server/examples/account.rs

@@ -17,7 +17,9 @@ use core::{fmt::Debug, marker::PhantomData};
 use std::time::Instant;
 
 use error_stack::{Report, ResultExt as _};
-use frunk::HList;;    Client, ClientConfig,
+use frunk::HList;
+use harpc_client::{
+    Client, ClientConfig,
     connection::{Connection, ConnectionCodec, ConnectionService},
     utils::invoke_call_discrete,
 };
@@ -118,6 +120,7 @@ impl Procedure for CreateAccount {
     const ID: <Self::Subsystem as Subsystem>::ProcedureId = AccountProcedureId::CreateAccount;
 }
 
+#[must_use]
 #[derive(Debug, Copy, Clone, PartialEq, Eq, Hash, derive_more::Display, derive_more::Error)]
 #[display("unable to fullfil account request")]
 pub struct AccountError;
@@ -138,7 +141,8 @@ struct AccountSystemImpl<S> {
 }
 
 impl<S> AccountSystemImpl<S> {
-    fn new() -> Self {
+    #[must_use]
+    const fn new() -> Self {
         Self {
             _scope: PhantomData,
         }
@@ -167,14 +171,20 @@ struct AccountSystemClient<S, C> {
 }
 
 impl<S, C> AccountSystemClient<S, C> {
-    fn new() -> Self {
+    const fn new() -> Self {
         Self {
             _service: PhantomData,
             _codec: PhantomData,
         }
     }
 }
 
+impl<S, C> Default for AccountSystemClient<S, C> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl<S, C> AccountSystem for AccountSystemClient<S, C>
 where
     S: ConnectionService<C>,
@@ -198,6 +208,13 @@ struct AccountServerDelegate<T> {
     subsystem: T,
 }
 
+impl<T> AccountServerDelegate<T> {
+    #[must_use]
+    const fn new(subsystem: T) -> Self {
+        Self { subsystem }
+    }
+}
+
 impl<T, C> SubsystemDelegate<C> for AccountServerDelegate<T>
 where
     T: AccountSystem<create_account(..): Send, ExecutionScope: Send> + Send + Sync,
@@ -244,9 +261,7 @@ async fn server() {
                 .layer(HandleReportLayer::new())
                 .layer(HandleBodyReportLayer::new())
         })
-        .register(AccountServerDelegate {
-            subsystem: AccountSystemImpl::new(),
-        });
+        .register(AccountServerDelegate::new(AccountSystemImpl::new()));
 
     let task = router.background_task(server.events());
     tokio::spawn(task.into_future());