1 files changed, 56 insertions, 0 deletions

diff --git a/tests/ui/issues/issue-21245.rs b/tests/ui/issues/issue-21245.rs
new file mode 100644
index 00000000000..c8e55a0cc20
--- /dev/null
+++ b/tests/ui/issues/issue-21245.rs
@@ -0,0 +1,56 @@
+// check-pass
+#![allow(dead_code)]
+// Regression test for issue #21245. Check that we are able to infer
+// the types in these examples correctly. It used to be that
+// insufficient type propagation caused the type of the iterator to be
+// incorrectly unified with the `*const` type to which it is coerced.
+
+// pretty-expanded FIXME #23616
+
+use std::ptr;
+
+trait IntoIterator {
+    type Iter: Iterator;
+
+    fn into_iter2(self) -> Self::Iter;
+}
+
+impl<I> IntoIterator for I where I: Iterator {
+    type Iter = I;
+
+    fn into_iter2(self) -> I {
+        self
+    }
+}
+
+fn desugared_for_loop_bad<T>(v: Vec<T>) {
+    match IntoIterator::into_iter2(v.iter()) {
+        mut iter => {
+            loop {
+                match ::std::iter::Iterator::next(&mut iter) {
+                    ::std::option::Option::Some(x) => {
+                        unsafe { ptr::read(x); }
+                    },
+                    ::std::option::Option::None => break
+                }
+            }
+        }
+    }
+}
+
+fn desugared_for_loop_good<T>(v: Vec<T>) {
+    match v.iter().into_iter() {
+        mut iter => {
+            loop {
+                match ::std::iter::Iterator::next(&mut iter) {
+                    ::std::option::Option::Some(x) => {
+                        unsafe { ptr::read(x); }
+                    },
+                    ::std::option::Option::None => break
+                }
+            }
+        }
+    }
+}
+
+fn main() {}