add #[must_use] to more futures and streams (#1309)

18 files changed, 19 insertions, 0 deletions

diff --git a/tokio-fs/src/create_dir.rs b/tokio-fs/src/create_dir.rs
index ac784075..f691a2b9 100644
--- a/tokio-fs/src/create_dir.rs
+++ b/tokio-fs/src/create_dir.rs
@@ -17,6 +17,7 @@ pub fn create_dir<P: AsRef<Path>>(path: P) -> CreateDirFuture<P> {
 
 /// Future returned by `create_dir`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct CreateDirFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/create_dir_all.rs b/tokio-fs/src/create_dir_all.rs
index 914c0b17..d9a84eb2 100644
--- a/tokio-fs/src/create_dir_all.rs
+++ b/tokio-fs/src/create_dir_all.rs
@@ -18,6 +18,7 @@ pub fn create_dir_all<P: AsRef<Path>>(path: P) -> CreateDirAllFuture<P> {
 
 /// Future returned by `create_dir_all`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct CreateDirAllFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/file/clone.rs b/tokio-fs/src/file/clone.rs
index 24a44306..899f3346 100644
--- a/tokio-fs/src/file/clone.rs
+++ b/tokio-fs/src/file/clone.rs
@@ -13,6 +13,7 @@ use std::task::Poll;
 ///
 /// Will panic if polled after returning an item or error.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct CloneFuture {
     file: Option<File>,
 }
diff --git a/tokio-fs/src/file/create.rs b/tokio-fs/src/file/create.rs
index bc4661cb..41ca554f 100644
--- a/tokio-fs/src/file/create.rs
+++ b/tokio-fs/src/file/create.rs
@@ -8,6 +8,7 @@ use std::task::Context;
 use std::task::Poll;
 
 /// Future returned by `File::create` and resolves to a `File` instance.
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 #[derive(Debug)]
 pub struct CreateFuture<P> {
     path: P,
diff --git a/tokio-fs/src/file/metadata.rs b/tokio-fs/src/file/metadata.rs
index a5aa4683..67be837a 100644
--- a/tokio-fs/src/file/metadata.rs
+++ b/tokio-fs/src/file/metadata.rs
@@ -11,6 +11,7 @@ const POLL_AFTER_RESOLVE: &str = "Cannot poll MetadataFuture after it resolves";
 
 /// Future returned by `File::metadata` and resolves to a `(File, Metadata)` instance.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct MetadataFuture {
     file: Option<File>,
 }
diff --git a/tokio-fs/src/file/open.rs b/tokio-fs/src/file/open.rs
index 5f7915ee..c25c2e1f 100644
--- a/tokio-fs/src/file/open.rs
+++ b/tokio-fs/src/file/open.rs
@@ -9,6 +9,7 @@ use std::task::Poll;
 
 /// Future returned by `File::open` and resolves to a `File` instance.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct OpenFuture<P: Unpin> {
     options: StdOpenOptions,
     path: P,
diff --git a/tokio-fs/src/file/seek.rs b/tokio-fs/src/file/seek.rs
index be0d997d..18ee4329 100644
--- a/tokio-fs/src/file/seek.rs
+++ b/tokio-fs/src/file/seek.rs
@@ -7,6 +7,7 @@ use std::task::Poll;
 
 /// Future returned by `File::seek`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct SeekFuture {
     inner: Option<File>,
     pos: io::SeekFrom,
diff --git a/tokio-fs/src/hard_link.rs b/tokio-fs/src/hard_link.rs
index b4a023b3..e18bac17 100644
--- a/tokio-fs/src/hard_link.rs
+++ b/tokio-fs/src/hard_link.rs
@@ -20,6 +20,7 @@ pub fn hard_link<P: AsRef<Path>, Q: AsRef<Path>>(src: P, dst: Q) -> HardLinkFutu
 
 /// Future returned by `hard_link`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct HardLinkFuture<P, Q>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/metadata.rs b/tokio-fs/src/metadata.rs
index 11a25249..e54a5851 100644
--- a/tokio-fs/src/metadata.rs
+++ b/tokio-fs/src/metadata.rs
@@ -17,6 +17,7 @@ where
 
 /// Future returned by `metadata`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct MetadataFuture<P>
 where
     P: AsRef<Path> + Send + 'static,
diff --git a/tokio-fs/src/read.rs b/tokio-fs/src/read.rs
index cfd0afe3..a6e1a98f 100644
--- a/tokio-fs/src/read.rs
+++ b/tokio-fs/src/read.rs
@@ -38,6 +38,7 @@ where
 
 /// A future used to open a file and read its entire contents into a buffer.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct ReadFile<P: AsRef<Path> + Send + Unpin + 'static> {
     state: State<P>,
 }
diff --git a/tokio-fs/src/read_dir.rs b/tokio-fs/src/read_dir.rs
index 01e36d01..9585518b 100644
--- a/tokio-fs/src/read_dir.rs
+++ b/tokio-fs/src/read_dir.rs
@@ -24,6 +24,7 @@ where
 
 /// Future returned by `read_dir`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct ReadDirFuture<P>
 where
     P: AsRef<Path> + Send + 'static,
@@ -68,6 +69,7 @@ where
 /// [`Stream`]: ../futures/stream/trait.Stream.html
 /// [`Err`]: https://doc.rust-lang.org/std/result/enum.Result.html#variant.Err
 #[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
 pub struct ReadDir(StdReadDir);
 
 impl Stream for ReadDir {
diff --git a/tokio-fs/src/read_link.rs b/tokio-fs/src/read_link.rs
index d5b9fe2d..980f922e 100644
--- a/tokio-fs/src/read_link.rs
+++ b/tokio-fs/src/read_link.rs
@@ -17,6 +17,7 @@ pub fn read_link<P: AsRef<Path>>(path: P) -> ReadLinkFuture<P> {
 
 /// Future returned by `read_link`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct ReadLinkFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/remove_dir.rs b/tokio-fs/src/remove_dir.rs
index b0de35e1..3e666c68 100644
--- a/tokio-fs/src/remove_dir.rs
+++ b/tokio-fs/src/remove_dir.rs
@@ -17,6 +17,7 @@ pub fn remove_dir<P: AsRef<Path>>(path: P) -> RemoveDirFuture<P> {
 
 /// Future returned by `remove_dir`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct RemoveDirFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/remove_file.rs b/tokio-fs/src/remove_file.rs
index ca8b8088..b09eae77 100644
--- a/tokio-fs/src/remove_file.rs
+++ b/tokio-fs/src/remove_file.rs
@@ -21,6 +21,7 @@ pub fn remove_file<P: AsRef<Path>>(path: P) -> RemoveFileFuture<P> {
 
 /// Future returned by `remove_file`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct RemoveFileFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/rename.rs b/tokio-fs/src/rename.rs
index 742ced04..670a9c7d 100644
--- a/tokio-fs/src/rename.rs
+++ b/tokio-fs/src/rename.rs
@@ -20,6 +20,7 @@ pub fn rename<P: AsRef<Path>, Q: AsRef<Path>>(from: P, to: Q) -> RenameFuture<P,
 
 /// Future returned by `rename`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct RenameFuture<P, Q>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/set_permissions.rs b/tokio-fs/src/set_permissions.rs
index d5bdfd67..e91c33b8 100644
--- a/tokio-fs/src/set_permissions.rs
+++ b/tokio-fs/src/set_permissions.rs
@@ -17,6 +17,7 @@ pub fn set_permissions<P: AsRef<Path>>(path: P, perm: fs::Permissions) -> SetPer
 
 /// Future returned by `set_permissions`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct SetPermissionsFuture<P>
 where
     P: AsRef<Path>,
diff --git a/tokio-fs/src/symlink_metadata.rs b/tokio-fs/src/symlink_metadata.rs
index cc450959..0cae53c5 100644
--- a/tokio-fs/src/symlink_metadata.rs
+++ b/tokio-fs/src/symlink_metadata.rs
@@ -21,6 +21,7 @@ where
 
 /// Future returned by `symlink_metadata`.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct SymlinkMetadataFuture<P>
 where
     P: AsRef<Path> + Send + 'static,
diff --git a/tokio-fs/src/write.rs b/tokio-fs/src/write.rs
index 4b63984c..d3d357ca 100644
--- a/tokio-fs/src/write.rs
+++ b/tokio-fs/src/write.rs
@@ -41,6 +41,7 @@ where
 /// A future used to open a file for writing and write the entire contents
 /// of some data to it.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless you `.await` or poll them"]
 pub struct WriteFile<P: AsRef<Path> + Send + Unpin + 'static, C: AsRef<[u8]> + Unpin> {
     state: State<P, C>,
 }