From b8588fb49542377ac69569ed03a7fa1adf70f3dc Mon Sep 17 00:00:00 2001
From: Niko Matsakis <niko@alum.mit.edu>
Date: Fri, 26 Aug 2016 16:14:44 -0400
Subject: [PATCH] Add a `Sized` bound to the `Comonoid` trait

Otherwise the type `(Self, Self)` is not well-formed, as tuples may not
have unsized members. See rust-lang/rust#33242 for details.
---
 src/lib.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/lib.rs b/src/lib.rs
index 060f276..6cfedc7 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -16,7 +16,7 @@
 /// implementation of [`Drop`](http://doc.rust-lang.org/std/ops/trait.Drop.html)
 /// and [`Clone`](http://doc.rust-lang.org/std/clone/trait.Clone.html),
 /// respectively.
-pub trait Comonoid {
+pub trait Comonoid: Sized {
     /// The dual to the monoidal unit.
     fn counit(self) -> ();
     /// The dual to the monoidal multiplication.