From cd291b8e516767eaae2edf1cb968d49a005eecfa Mon Sep 17 00:00:00 2001
From: mibac138 <5672750+mibac138@users.noreply.github.com>
Date: Fri, 8 May 2020 00:07:18 +0200
Subject: [PATCH] Adjust cfg(version) to lang team decision

---
 src/librustc_attr/build.rs   | 3 ++-
 src/librustc_attr/builtin.rs | 7 +++++--
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/src/librustc_attr/build.rs b/src/librustc_attr/build.rs
index d230ba91039ad..863f2b7337b25 100644
--- a/src/librustc_attr/build.rs
+++ b/src/librustc_attr/build.rs
@@ -1,4 +1,5 @@
 fn main() {
     println!("cargo:rerun-if-changed=build.rs");
-    println!("cargo:rerun-if-env-changed=CFG_VERSION");
+    println!("cargo:rerun-if-env-changed=CFG_RELEASE");
+    println!("cargo:rerun-if-env-changed=CFG_RELEASE_CHANNEL");
 }
diff --git a/src/librustc_attr/builtin.rs b/src/librustc_attr/builtin.rs
index ce38e3f5f4e4e..a592bbc2bf918 100644
--- a/src/librustc_attr/builtin.rs
+++ b/src/librustc_attr/builtin.rs
@@ -652,9 +652,12 @@ pub fn eval_condition(
                     return false;
                 }
             };
-            let version = Version::parse(env!("CFG_VERSION")).unwrap();
+            let channel = env!("CFG_RELEASE_CHANNEL");
+            let nightly = channel == "nightly" || channel == "dev";
+            let rustc_version = Version::parse(env!("CFG_RELEASE")).unwrap();
 
-            version >= min_version
+            // See https://github.com/rust-lang/rust/issues/64796#issuecomment-625474439 for details
+            if nightly { rustc_version > min_version } else { rustc_version >= min_version }
         }
         ast::MetaItemKind::List(ref mis) => {
             for mi in mis.iter() {