From 247b58b4f4de332964ec26e265a6150d630d60d7 Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Sun, 24 Sep 2017 23:57:42 -0700
Subject: [PATCH] Allow unused extern crate again

This is a partial revert of #42588. There is a usability concern
reported in #44294 that was not considered in the discussion of the PR,
so I would like to back this out of 1.21. As is, I think users would
have a worse and more confusing experience with this lint enabled by
default. We can re-enabled once there are better diagnostics or the case
in #44294 does not trigger the lint.
---
 src/librustc/lint/builtin.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/librustc/lint/builtin.rs b/src/librustc/lint/builtin.rs
index 21852468146..5fe75d8ca71 100644
--- a/src/librustc/lint/builtin.rs
+++ b/src/librustc/lint/builtin.rs
@@ -30,7 +30,7 @@ declare_lint! {
 
 declare_lint! {
     pub UNUSED_EXTERN_CRATES,
-    Warn,
+    Allow,
     "extern crates that are never used"
 }