From e575d35da2dde16ee487e2e6904c43e0b0d43661 Mon Sep 17 00:00:00 2001
From: Matt Fellenz <matt@felle.nz>
Date: Fri, 15 Apr 2022 08:26:12 -0700
Subject: [PATCH] Improve documentation for FromRequest::Future

---
 actix-web/src/extract.rs | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/actix-web/src/extract.rs b/actix-web/src/extract.rs
index 1b2f0bd19..684afb0aa 100644
--- a/actix-web/src/extract.rs
+++ b/actix-web/src/extract.rs
@@ -67,6 +67,10 @@ pub trait FromRequest: Sized {
     type Error: Into<Error>;
 
     /// Future that resolves to a Self.
+    ///
+    /// To refer to the type of an async function or block here, you have two options.
+    /// The first is to use a boxed future such as `futures::future::BoxFuture`. This works on stable and nightly.
+    /// The second is to use `impl Future`, which requires `#![feature(type_alias_impl_trait)]` so only works on nightly.
     type Future: Future<Output = Result<Self, Self::Error>>;
 
     /// Create a Self from request parts asynchronously.