diff --git a/src/chain.rs b/src/chain.rs
new file mode 100644
index 0000000..78f824f
--- /dev/null
+++ b/src/chain.rs
@@ -0,0 +1,12 @@
+use crate::Chain;
+use std::error::Error as StdError;
+
+impl<'a> Iterator for Chain<'a> {
+    type Item = &'a (dyn StdError + 'static);
+
+    fn next(&mut self) -> Option<Self::Item> {
+        let next = self.next?;
+        self.next = next.source();
+        Some(next)
+    }
+}
diff --git a/src/error.rs b/src/error.rs
index f51033e..2953b2b 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -726,13 +726,3 @@ impl From<Error> for Box<dyn StdError + 'static> {
         Box::<dyn StdError + Send + Sync>::from(error)
     }
 }
-
-impl<'a> Iterator for Chain<'a> {
-    type Item = &'a (dyn StdError + 'static);
-
-    fn next(&mut self) -> Option<Self::Item> {
-        let next = self.next?;
-        self.next = next.source();
-        Some(next)
-    }
-}
diff --git a/src/lib.rs b/src/lib.rs
index ab552ec..ad0aa08 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -169,6 +169,7 @@
 
 #[macro_use]
 mod backtrace;
+mod chain;
 mod context;
 mod error;
 mod fmt;