From f5e4f78eb7e3bad90b8dbbd20c58426817a4ffbf Mon Sep 17 00:00:00 2001
From: Cameron Steffen <cam.steffen94@gmail.com>
Date: Thu, 30 Sep 2021 12:06:30 -0500
Subject: [PATCH] Add private arg to fmt::UnsafeArg

---
 library/core/src/fmt/mod.rs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index 3a0c19d7de56f..31da3ef87b951 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -270,9 +270,10 @@ pub struct ArgumentV1<'a> {
 /// of `format_args!(..)` and reduce the scope of the `unsafe` block.
 #[allow(missing_debug_implementations)]
 #[doc(hidden)]
-#[non_exhaustive]
 #[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
-pub struct UnsafeArg;
+pub struct UnsafeArg {
+    _private: (),
+}
 
 impl UnsafeArg {
     /// See documentation where `UnsafeArg` is required to know when it is safe to
@@ -281,7 +282,7 @@ impl UnsafeArg {
     #[unstable(feature = "fmt_internals", reason = "internal to format_args!", issue = "none")]
     #[inline(always)]
     pub unsafe fn new() -> Self {
-        Self
+        Self { _private: () }
     }
 }