added comments about how we use the reference to FullNodeTypes to bui…

…ld the components

crates/node/builder/src/launch/common.rs

@@ -546,6 +546,7 @@ where
             blockchain_db,
             tree_config,
             canon_state_notification_sender,
+            // we store here a reference to T.
             phantom_data: PhantomData,
         };
 
@@ -822,6 +823,8 @@ pub struct WithMeteredProviders<DB, T> {
     blockchain_db: BlockchainProvider<DB>,
     canon_state_notification_sender: CanonStateNotificationSender,
     tree_config: BlockchainTreeConfig,
+    // this field is used to store a reference to the FullNodeTypes so that we
+    // can build the components in `with_components` method.
     phantom_data: PhantomData<T>,
 }
 

crates/node/builder/src/launch/mod.rs

@@ -126,6 +126,8 @@ where
                 info!(target: "reth::cli", "\n{}", this.chain_spec().display_hardforks());
             })
             .with_metrics()
+            // passing FullNodeTypes as type parameter here so that we can build
+            // later the components.
             .with_blockchain_db::<T>().await?
             .with_components(components_builder, on_component_initialized).await?;