diff --git a/src/adaptors/mod.rs b/src/adaptors/mod.rs
index 84bbf98e0..564d83439 100644
--- a/src/adaptors/mod.rs
+++ b/src/adaptors/mod.rs
@@ -127,8 +127,8 @@ where
     I: Iterator,
     J: Iterator<Item = I::Item>,
 {
-    i: I,
-    j: J,
+    i: Fuse<I>,
+    j: Fuse<J>,
     next_coming_from_j: bool,
 }
 
@@ -139,8 +139,8 @@ where
     J: Iterator<Item = I::Item>,
 {
     InterleaveShortest {
-        i,
-        j,
+        i: i.fuse(),
+        j: j.fuse(),
         next_coming_from_j: false,
     }
 }
@@ -231,8 +231,8 @@ where
 
 impl<I, J> FusedIterator for InterleaveShortest<I, J>
 where
-    I: FusedIterator,
-    J: FusedIterator<Item = I::Item>,
+    I: Iterator,
+    J: Iterator<Item = I::Item>,
 {
 }
 
diff --git a/tests/quick.rs b/tests/quick.rs
index f96418f40..c0f765e10 100644
--- a/tests/quick.rs
+++ b/tests/quick.rs
@@ -1880,7 +1880,7 @@ quickcheck! {
 
     fn fused_interleave_shortest(a: Iter<i16>, b: Iter<i16>) -> bool
     {
-        !is_fused(a.clone().interleave_shortest(b.clone())) &&
+        is_fused(a.clone().interleave_shortest(b.clone())) &&
         is_fused(a.fuse().interleave_shortest(b.fuse()))
     }