From cd7c376abcfa2041b99654d3cdf0a487abc15aee Mon Sep 17 00:00:00 2001
From: Yu Ding <dingyu02@baidu.com>
Date: Tue, 20 Mar 2018 19:51:33 -0700
Subject: [PATCH] Allowing stable channel rustc in Rust\'s style

---
 src/main.rs | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index 2575d16..5917de6 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -140,13 +140,21 @@ fn run() -> Result<ExitStatus> {
                 sysroot.src()?
             },
             Channel::Stable | Channel::Beta => {
-                writeln!(
-                    io::stderr(),
-                    "WARNING: the sysroot can't be built for the {:?} channel. \
-                     Switch to nightly.",
-                    meta.channel
-                ).ok();
-                return cargo::run(&args, verbose);
+                if env::var("RUSTC_BOOTSTRAP").is_ok() {
+                    if let Some(src) = rustc::Src::from_env() {
+                        src
+                    } else {
+                        sysroot.src()?
+                    }
+                } else {
+                    writeln!(
+                        io::stderr(),
+                        "WARNING: the sysroot can't be built for the {:?} channel. \
+                        Switch to nightly.",
+                        meta.channel
+                    ).ok();
+                    return cargo::run(&args, verbose);
+                }
             }
         };