1 files changed, 15 insertions, 0 deletions

diff --git a/src/test/ui/impl-trait/issues/issue-70877.stderr b/src/test/ui/impl-trait/issues/issue-70877.stderr
new file mode 100644
index 00000000000..b6861039f6a
--- /dev/null
+++ b/src/test/ui/impl-trait/issues/issue-70877.stderr
@@ -0,0 +1,15 @@
+error[E0271]: type mismatch resolving `<Bar as Iterator>::Item == Box<(dyn for<'r> Fn(&'r (dyn ToString + 'r)) -> Option<String> + 'static)>`
+  --> $DIR/issue-70877.rs:7:12
+   |
+LL | type FooRet = impl std::fmt::Debug;
+   |               -------------------- the found opaque type
+...
+LL | type Foo = impl Iterator<Item = FooItem>;
+   |            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected enum `Option`, found opaque type
+   |
+   = note: expected struct `Box<(dyn for<'r> Fn(&'r (dyn ToString + 'r)) -> Option<String> + 'static)>`
+              found struct `Box<(dyn for<'r> Fn(&'r (dyn ToString + 'r)) -> impl Debug + 'static)>`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0271`.