From 3a648b65800c5b93531afcec873b5c2da85c8fa2 Mon Sep 17 00:00:00 2001
From: Alex Crichton <alex@alexcrichton.com>
Date: Mon, 9 Sep 2019 09:28:07 -0700
Subject: [PATCH] Move handling of `-Dwarnings` to `builder.rs`

---
 src/bootstrap/bin/rustc.rs | 3 ---
 src/bootstrap/builder.rs   | 4 ++--
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 8be70c5a287..9c7fba0dd78 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -111,9 +111,6 @@ fn main() {
             cmd.arg("-Zunstable-options");
             cmd.arg("-Wrustc::internal");
         }
-        if env::var_os("RUSTC_DENY_WARNINGS").is_some() {
-            cmd.arg("-Dwarnings");
-        }
     }
 
     if let Some(target) = target {
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 095770f7650..60673cf7cdd 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -1055,8 +1055,8 @@ impl<'a> Builder<'a> {
 
         cargo.env("RUSTC_VERBOSE", self.verbosity.to_string());
 
-        if self.config.deny_warnings {
-            cargo.env("RUSTC_DENY_WARNINGS", "1");
+        if self.config.deny_warnings && !mode.is_tool() {
+            rustflags.arg("-Dwarnings");
         }
 
         // Throughout the build Cargo can execute a number of build scripts