From 001b93a558502f89ad840b7afc6c592e9dfdbd3f Mon Sep 17 00:00:00 2001
From: Odysseas Lamtzidis <odyslam@gmail.com>
Date: Mon, 13 Sep 2021 16:52:59 +0300
Subject: [PATCH] Inform users to update in case of error [E0658]

If users try to build/check the project with an older version of rust, it will fail due to this error: `error[E0658]: use of unstable library feature 'map_into_keys_values'`.

It is fixed with `rustup update`
---
 README.md | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/README.md b/README.md
index cb2e6427d61c5..fb45cd5619e50 100644
--- a/README.md
+++ b/README.md
@@ -105,6 +105,11 @@ cargo test
 cargo doc --open
 cargo build [--release]
 ```
+**Tip**: If you encounter the following error when building the project, please update your Rust toolchain with `rustup update`.
+
+```
+error[E0658]: use of unstable library feature 'map_into_keys_values'
+```
 
 ### CLI Help