From b3fbfe474b40b5747161668d830e7589af71be92 Mon Sep 17 00:00:00 2001
From: Jonas Schievink <jonasschievink@gmail.com>
Date: Sun, 27 Jun 2021 03:54:06 +0200
Subject: [PATCH] Make `fmt::Arguments::as_str` unstably const

---
 library/core/src/fmt/mod.rs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index 409a84367a7d8..9ed49c1e3024f 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -444,8 +444,9 @@ impl<'a> Arguments<'a> {
     /// assert_eq!(format_args!("{}", 1).as_str(), None);
     /// ```
     #[stable(feature = "fmt_as_str", since = "1.52.0")]
+    #[rustc_const_unstable(feature = "const_arguments_as_str", issue = "none")]
     #[inline]
-    pub fn as_str(&self) -> Option<&'static str> {
+    pub const fn as_str(&self) -> Option<&'static str> {
         match (self.pieces, self.args) {
             ([], []) => Some(""),
             ([s], []) => Some(s),