Rollup merge of #22596 - alexcrichton:fix-some-impls, r=huonw

 This commit removes many unnecessary `unsafe impl` blocks as well as pushing the
needed implementations to the lowest level possible. I noticed that the bounds
for `RwLock` are a little off when reviewing #22574 and wanted to ensure that we
had our story straight on these implementations.

1 files changed, 27 insertions, 0 deletions

diff --git a/src/test/run-pass/std-sync-right-kind-impls.rs b/src/test/run-pass/std-sync-right-kind-impls.rs
new file mode 100644
index 00000000000..d2d72ed1661
--- /dev/null
+++ b/src/test/run-pass/std-sync-right-kind-impls.rs
@@ -0,0 +1,27 @@
+// Copyright 2015 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.
+
+use std::sync;
+
+fn assert_both<T: Sync + Send>() {}
+
+fn main() {
+    assert_both::<sync::StaticMutex>();
+    assert_both::<sync::StaticCondvar>();
+    assert_both::<sync::StaticRwLock>();
+    assert_both::<sync::Mutex<()>>();
+    assert_both::<sync::Condvar>();
+    assert_both::<sync::RwLock<()>>();
+    assert_both::<sync::Semaphore>();
+    assert_both::<sync::Barrier>();
+    assert_both::<sync::Arc<()>>();
+    assert_both::<sync::Weak<()>>();
+    assert_both::<sync::Once>();
+}