1 files changed, 24 insertions, 0 deletions
diff --git a/tests/ui/lifetimes/bare-trait-object-borrowck.rs b/tests/ui/lifetimes/bare-trait-object-borrowck.rs
new file mode 100644
index 00000000000..45f5e4ae129
--- /dev/null
+++ b/tests/ui/lifetimes/bare-trait-object-borrowck.rs
@@ -0,0 +1,24 @@
+#![allow(bare_trait_objects)]
+// check-pass
+pub struct FormatWith<'a, I, F> {
+    sep: &'a str,
+    /// FormatWith uses interior mutability because Display::fmt takes &self.
+    inner: RefCell<Option<(I, F)>>,
+}
+
+use std::cell::RefCell;
+use std::fmt;
+
+struct Layout;
+
+pub fn new_format<'a, I, F>(iter: I, separator: &'a str, f: F) -> FormatWith<'a, I, F>
+where
+    I: Iterator,
+    F: FnMut(I::Item, &mut FnMut(&fmt::Display) -> fmt::Result) -> fmt::Result,
+{
+    FormatWith { sep: separator, inner: RefCell::new(Some((iter, f))) }
+}
+
+fn main() {
+    let _ = new_format(0..32, " | ", |i, f| f(&format_args!("0x{:x}", i)));
+}