From 8faaef66c921c7c65fa73727ae5bd5d4e4fe7a76 Mon Sep 17 00:00:00 2001
From: QuietMisdreavus <grey@quietmisdreavus.net>
Date: Thu, 13 Dec 2018 15:23:36 -0600
Subject: [PATCH] add test for parsing comments in doctest headers

---
 src/test/rustdoc/comment-in-doctest.rs | 30 ++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 src/test/rustdoc/comment-in-doctest.rs

diff --git a/src/test/rustdoc/comment-in-doctest.rs b/src/test/rustdoc/comment-in-doctest.rs
new file mode 100644
index 0000000000000..3468bb7bda473
--- /dev/null
+++ b/src/test/rustdoc/comment-in-doctest.rs
@@ -0,0 +1,30 @@
+// Copyright 2018 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.
+
+// compile-flags:--test
+
+// comments, both doc comments and regular ones, used to trick rustdoc's doctest parser into
+// thinking that everything after it was part of the regular program. combined with the libsyntax
+// parser loop failing to detect the manual main function, it would wrap everything in `fn main`,
+// which would cause the doctest to fail as the "extern crate" declaration was no longer valid.
+// oddly enough, it would pass in 2018 if a crate was in the extern prelude. see
+// https://github.com/rust-lang/rust/issues/56727
+
+//! ```
+//! // crate: proc-macro-test
+//! //! this is a test
+//!
+//! // used to pull in proc-macro specific items
+//! extern crate proc_macro;
+//!
+//! use proc_macro::TokenStream;
+//!
+//! # fn main() {}
+//! ```