1 files changed, 21 insertions, 0 deletions
diff --git a/library/core/tests/iter.rs b/library/core/tests/iter.rs
index 691767edea6..bc5421bfb5f 100644
--- a/library/core/tests/iter.rs
+++ b/library/core/tests/iter.rs
@@ -2,6 +2,7 @@
 
 use core::cell::Cell;
 use core::convert::TryFrom;
+use core::iter::TrustedRandomAccess;
 use core::iter::*;
 
 /// An iterator wrapper that panics whenever `next` or `next_back` is called
@@ -602,6 +603,26 @@ fn test_zip_nth_back_side_effects_exhausted() {
 }
 
 #[test]
+fn test_zip_trusted_random_access_composition() {
+    let a = [0, 1, 2, 3, 4];
+    let b = a;
+    let c = a;
+
+    let a = a.iter().copied();
+    let b = b.iter().copied();
+    let mut c = c.iter().copied();
+    c.next();
+
+    let mut z1 = a.zip(b);
+    assert_eq!(z1.next().unwrap(), (0, 0));
+
+    let mut z2 = z1.zip(c);
+    fn assert_trusted_random_access<T: TrustedRandomAccess>(_a: &T) {}
+    assert_trusted_random_access(&z2);
+    assert_eq!(z2.next().unwrap(), ((1, 1), 1));
+}
+
+#[test]
 fn test_iterator_step_by() {
     // Identity
     let mut it = (0..).step_by(1).take(3);