1 files changed, 38 insertions, 0 deletions
diff --git a/src/test/ui/iterators/iter-map-fold-type-length.rs b/src/test/ui/iterators/iter-map-fold-type-length.rs
new file mode 100644
index 000000000..8ce4fcd87
--- /dev/null
+++ b/src/test/ui/iterators/iter-map-fold-type-length.rs
@@ -0,0 +1,38 @@
+// run-pass
+//! Check that type lengths don't explode with `Map` folds.
+//!
+//! The normal limit is a million, and this test used to exceed 1.5 million, but
+//! now we can survive an even tighter limit. Still seems excessive though...
+#![type_length_limit = "256000"]
+
+// Custom wrapper so Iterator methods aren't specialized.
+struct Iter<I>(I);
+
+impl<I> Iterator for Iter<I>
+where
+    I: Iterator
+{
+    type Item = I::Item;
+
+    fn next(&mut self) -> Option<Self::Item> {
+        self.0.next()
+    }
+}
+
+fn main() {
+    let c = Iter(0i32..10)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .map(|x| x)
+        .count();
+    assert_eq!(c, 10);
+}