commit 40d4ffdff6a713e6681bbad168374b1dd04d2d00
author David Tolnay <dtolnay@gmail.com> Sun Aug 12 13:49:09 2018 -0700
committer David Tolnay <dtolnay@gmail.com> Tue Aug 14 10:25:14 2018 -0700
tree 7edad04b06a4b596f7052e0c24f48786102904c7
parent 60b48bd560f89fd8f0aa499803109126f30c079e

Use TokenStream::extend

src/unstable.rs

diff --git a/src/unstable.rs b/src/unstable.rs
index e024205..1292edf 100644
--- a/src/unstable.rs
+++ b/src/unstable.rs
@@ -160,18 +160,11 @@
     fn extend<I: IntoIterator<Item = TokenTree>>(&mut self, streams: I) {
         match self {
             TokenStream::Nightly(tts) => {
-                *tts = tts
-                    .clone()
-                    .into_iter()
-                    .chain(
-                        streams
-                            .into_iter()
-                            .map(TokenStream::from)
-                            .flat_map(|t| match t {
-                                TokenStream::Nightly(tts) => tts.into_iter(),
-                                _ => panic!(),
-                            }),
-                    ).collect();
+                tts.extend(
+                    streams
+                        .into_iter()
+                        .map(|t| TokenStream::from(t).unwrap_nightly()),
+                );
             }
             TokenStream::Stable(tts) => tts.extend(streams),
         }