From f4fa59470a9629bc3bd8f5ee8cc76b12bc6278c0 Mon Sep 17 00:00:00 2001
From: thiolliere <gui.thiolliere@gmail.com>
Date: Wed, 29 Jan 2020 13:26:09 +0100
Subject: [PATCH] doc (#4761)

---
 substrate/frame/support/src/storage/generator/linked_map.rs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/substrate/frame/support/src/storage/generator/linked_map.rs b/substrate/frame/support/src/storage/generator/linked_map.rs
index 14bef77c9e..face87edf9 100644
--- a/substrate/frame/support/src/storage/generator/linked_map.rs
+++ b/substrate/frame/support/src/storage/generator/linked_map.rs
@@ -433,6 +433,8 @@ where
 		}
 	}
 
+	/// The translation happens in-place, new keys are inserted at the same time as old keys are
+	/// removed, thus new keys must not collide with still remaining old keys.
 	fn translate<K2, V2, TK, TV>(translate_key: TK, translate_val: TV) -> Result<(), Option<K2>>
 		where K2: FullCodec + Clone, V2: Decode, TK: Fn(K2) -> K, TV: Fn(V2) -> V
 	{