From 26a8c3b6b6ae8cf45a5d6fb37373e8638a8f7b78 Mon Sep 17 00:00:00 2001
From: Jonathan Buchanan <jonathan.russ.buchanan@gmail.com>
Date: Sat, 2 Apr 2016 09:39:27 -0400
Subject: [PATCH 1/3] Wrote a failing test case

---
 .../lint-non-snake-case-two-underscores.rs    | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 src/test/run-pass/lint-non-snake-case-two-underscores.rs

diff --git a/src/test/run-pass/lint-non-snake-case-two-underscores.rs b/src/test/run-pass/lint-non-snake-case-two-underscores.rs
new file mode 100644
index 0000000000000..380af72eba4ca
--- /dev/null
+++ b/src/test/run-pass/lint-non-snake-case-two-underscores.rs
@@ -0,0 +1,42 @@
+// Copyright 2014 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![deny(non_snake_case)]
+#![allow(dead_code)]
+
+// These tests should not fail because they all begin with '__'.
+
+struct Foo {
+    __FooVariable: i32,
+    __cOoKiE: f64
+}
+
+impl Foo {
+    fn __TestMethod() { }
+    fn __nOn____snake__CASE() { }
+}
+
+trait X {
+    fn __ABC() { }
+    fn __X_y__ZZ() { }
+}
+
+impl X for Foo {
+    fn __ABC() { }
+    fn __X_y__ZZ() { }
+}
+
+fn __BISCUIT() { }
+fn __THIs_____iSNoT____snaKE____caSE() { }
+
+fn main() {
+    let __barXYZ: i32 = 0;
+    let __Foo22 = "str";
+}

From cf3766e6f7d21eafc27e004fa9d754d343c754e6 Mon Sep 17 00:00:00 2001
From: Jonathan Buchanan <jonathan.russ.buchanan@gmail.com>
Date: Sat, 2 Apr 2016 11:11:07 -0400
Subject: [PATCH 2/3] Anything that begins with '__' and should be checked for
 snake case will not be checked for snake case

This satisfies the test case I made earlier
---
 src/librustc_lint/bad_style.rs | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/librustc_lint/bad_style.rs b/src/librustc_lint/bad_style.rs
index 66d435a7581d9..1412e787e6c8c 100644
--- a/src/librustc_lint/bad_style.rs
+++ b/src/librustc_lint/bad_style.rs
@@ -179,6 +179,9 @@ impl NonSnakeCase {
 
     fn check_snake_case(&self, cx: &LateContext, sort: &str, name: &str, span: Option<Span>) {
         fn is_snake_case(ident: &str) -> bool {
+            if ident.starts_with("__") {
+                return true;
+            }
             if ident.is_empty() {
                 return true;
             }

From b924582f403462d61573d8f7bad6ee486813739d Mon Sep 17 00:00:00 2001
From: Jonathan Buchanan <jonathan.russ.buchanan@gmail.com>
Date: Sat, 2 Apr 2016 11:14:18 -0400
Subject: [PATCH 3/3] Added a comment

---
 src/librustc_lint/bad_style.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/librustc_lint/bad_style.rs b/src/librustc_lint/bad_style.rs
index 1412e787e6c8c..11d68b83c4e64 100644
--- a/src/librustc_lint/bad_style.rs
+++ b/src/librustc_lint/bad_style.rs
@@ -179,6 +179,7 @@ impl NonSnakeCase {
 
     fn check_snake_case(&self, cx: &LateContext, sort: &str, name: &str, span: Option<Span>) {
         fn is_snake_case(ident: &str) -> bool {
+            // Items starting with '__' will be counted as snake case even if they are not
             if ident.starts_with("__") {
                 return true;
             }