From b2492874bcd71bd1bfeaf98a799a43bf4ff4e87b Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Mon, 20 Feb 2023 13:39:31 -0800
Subject: [PATCH] Support const block syntax in ensure! macro

---
 src/ensure.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/ensure.rs b/src/ensure.rs
index 0ab4471..c40cb92 100644
--- a/src/ensure.rs
+++ b/src/ensure.rs
@@ -231,6 +231,11 @@ macro_rules! __parse_ensure {
         $crate::__parse_ensure!(atom $stack $bail ($($fuel)*) {($($buf)* $unsafe $block) $($parse)*} ($($rest)*) $($rest)*)
     };
 
+    (0 $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} ($const:tt $block:tt $($dup:tt)*) const {$($body:tt)*} $($rest:tt)*) => {
+        // TODO: this is mostly useless due to https://github.com/rust-lang/rust/issues/86730
+        $crate::__parse_ensure!(atom $stack $bail ($($fuel)*) {($($buf)* $const $block) $($parse)*} ($($rest)*) $($rest)*)
+    };
+
     (0 $stack:tt $bail:tt (~$($fuel:tt)*) {($($buf:tt)*) $($parse:tt)*} $dup:tt $lit:literal $($rest:tt)*) => {
         $crate::__parse_ensure!(atom $stack $bail ($($fuel)*) {($($buf)* $lit) $($parse)*} ($($rest)*) $($rest)*)
     };