Add #[must_use] to more types

Author: taiki-e

futures-util/src/future/into_stream.rs

@@ -5,7 +5,7 @@ use futures_core::task::{Context, Poll};
 use pin_utils::unsafe_pinned;
 
 /// Stream for the [`into_stream`](super::FutureExt::into_stream) method.
-#[must_use = "futures do nothing unless polled"]
+#[must_use = "streams do nothing unless polled"]
 #[derive(Debug)]
 pub struct IntoStream<Fut: Future> {
     future: Option<Fut>

futures-util/src/io/close.rs

@@ -6,6 +6,7 @@ use std::pin::Pin;
 
 /// Future for the [`close`](super::AsyncWriteExt::close) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct Close<'a, W: ?Sized + Unpin> {
     writer: &'a mut W,
 }

futures-util/src/io/copy_into.rs

@@ -7,6 +7,7 @@ use std::pin::Pin;
 
 /// Future for the [`copy_into`](super::AsyncReadExt::copy_into) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct CopyInto<'a, R: ?Sized + Unpin, W: ?Sized + Unpin> {
     reader: &'a mut R,
     read_done: bool,

futures-util/src/io/flush.rs

@@ -6,6 +6,7 @@ use std::pin::Pin;
 
 /// Future for the [`flush`](super::AsyncWriteExt::flush) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct Flush<'a, W: ?Sized + Unpin> {
     writer: &'a mut W,
 }

futures-util/src/io/lines.rs

@@ -8,6 +8,7 @@ use super::read_line::read_line_internal;
 
 /// Stream for the [`lines`](super::AsyncBufReadExt::lines) method.
 #[derive(Debug)]
+#[must_use = "streams do nothing unless polled"]
 pub struct Lines<R> {
     reader: R,
     buf: String,

futures-util/src/io/read.rs

@@ -6,6 +6,7 @@ use std::pin::Pin;
 
 /// Future for the [`read`](super::AsyncReadExt::read) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct Read<'a, R: ?Sized + Unpin> {
     reader: &'a mut R,
     buf: &'a mut [u8],

futures-util/src/io/read_exact.rs

@@ -7,6 +7,7 @@ use std::pin::Pin;
 
 /// Future for the [`read_exact`](super::AsyncReadExt::read_exact) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct ReadExact<'a, R: ?Sized + Unpin> {
     reader: &'a mut R,
     buf: &'a mut [u8],

futures-util/src/io/read_line.rs

@@ -9,6 +9,7 @@ use super::read_until::read_until_internal;
 
 /// Future for the [`read_line`](super::AsyncBufReadExt::read_line) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct ReadLine<'a, R: ?Sized + Unpin> {
     reader: &'a mut R,
     buf: &'a mut String,

futures-util/src/io/read_to_end.rs

@@ -7,6 +7,7 @@ use std::vec::Vec;
 
 /// Future for the [`read_to_end`](super::AsyncReadExt::read_to_end) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct ReadToEnd<'a, R: ?Sized + Unpin> {
     reader: &'a mut R,
     buf: &'a mut Vec<u8>,

futures-util/src/io/read_until.rs

@@ -7,6 +7,7 @@ use std::pin::Pin;
 
 /// Future for the [`read_until`](super::AsyncBufReadExt::read_until) method.
 #[derive(Debug)]
+#[must_use = "futures do nothing unless polled"]
 pub struct ReadUntil<'a, R: ?Sized + Unpin> {
     reader: &'a mut R,
     byte: u8,