From c5f59ed83dfb3be8d8cd08121cbc024726e99fa3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bastian=20K=C3=B6cher?= <bkchr@users.noreply.github.com>
Date: Mon, 27 Jul 2020 10:28:05 +0200
Subject: [PATCH] Try to workaround the invalid compilation (#159)

There is probably some bug in rustc which result in an invalid
compilation when using an `expect` at the given position. I'm still not
sure why this is happening, but this fix should fix it for now.
---
 cumulus/runtime/src/validate_block/implementation.rs | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/cumulus/runtime/src/validate_block/implementation.rs b/cumulus/runtime/src/validate_block/implementation.rs
index d891017739..fd324f7592 100644
--- a/cumulus/runtime/src/validate_block/implementation.rs
+++ b/cumulus/runtime/src/validate_block/implementation.rs
@@ -253,8 +253,9 @@ impl<B: BlockT> Storage for WitnessStorage<B> {
 		};
 
 		for x in TrieDBIterator::new_prefixed(&trie, prefix).expect("Creates trie iterator") {
-			let (key, _) = x.expect("Iterating trie iterator");
-			self.overlay.insert(key, None);
+			if let Ok((key, _)) = x {
+				self.overlay.insert(key, None);
+			}
 		}
 	}