Add tokio support to unused_ui_amount as well.

Author: nmathewson

Cargo.toml

@@ -49,6 +49,7 @@ serde = { version = "1.0", features = ["derive"] }
 syn = { version = "1.0", features = ["full"] }
 futures = "0.3"
 parking_lot = "0.11.2"
+tokio = { version = "1", features = ["io-util"] }
 
 [build-dependencies]
 rustc_tools_util = { version = "0.2", path = "rustc_tools_util" }

clippy_lints/src/unused_io_amount.rs

@@ -107,11 +107,13 @@ fn check_method_call(cx: &LateContext<'_>, call: &hir::Expr<'_>, expr: &hir::Exp
         let symbol = path.ident.as_str();
         let read_trait = if is_await {
             match_trait_method(cx, call, &paths::FUTURES_IO_ASYNCREADEXT)
+                || match_trait_method(cx, call, &paths::TOKIO_IO_ASYNCREADEXT)
         } else {
             match_trait_method(cx, call, &paths::IO_READ)
         };
         let write_trait = if is_await {
             match_trait_method(cx, call, &paths::FUTURES_IO_ASYNCWRITEEXT)
+                || match_trait_method(cx, call, &paths::TOKIO_IO_ASYNCWRITEEXT)
         } else {
             match_trait_method(cx, call, &paths::IO_WRITE)
         };

clippy_utils/src/paths.rs

@@ -198,6 +198,10 @@ pub const SYM_MODULE: [&str; 3] = ["rustc_span", "symbol", "sym"];
 pub const SYNTAX_CONTEXT: [&str; 3] = ["rustc_span", "hygiene", "SyntaxContext"];
 pub const TO_OWNED_METHOD: [&str; 4] = ["alloc", "borrow", "ToOwned", "to_owned"];
 pub const TO_STRING_METHOD: [&str; 4] = ["alloc", "string", "ToString", "to_string"];
+#[allow(clippy::invalid_paths)] // internal lints do not know about all external crates
+pub const TOKIO_IO_ASYNCREADEXT: [&str; 5] = ["tokio", "io", "util", "async_read_ext", "AsyncReadExt"];
+#[allow(clippy::invalid_paths)] // internal lints do not know about all external crates
+pub const TOKIO_IO_ASYNCWRITEEXT: [&str; 5] = ["tokio", "io", "util", "async_write_ext", "AsyncWriteExt"];
 pub const TRY_FROM: [&str; 4] = ["core", "convert", "TryFrom", "try_from"];
 pub const VEC_AS_MUT_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_mut_slice"];
 pub const VEC_AS_SLICE: [&str; 4] = ["alloc", "vec", "Vec", "as_slice"];

tests/compile-test.rs

@@ -29,6 +29,7 @@ static TEST_DEPENDENCIES: &[&str] = &[
     "serde",
     "serde_derive",
     "syn",
+    "tokio",
     "parking_lot",
 ];
 
@@ -50,6 +51,8 @@ extern crate parking_lot;
 extern crate quote;
 #[allow(unused_extern_crates)]
 extern crate syn;
+#[allow(unused_extern_crates)]
+extern crate tokio;
 
 /// Produces a string with an `--extern` flag for all UI test crate
 /// dependencies.

tests/ui/unused_io_amount.rs

@@ -95,4 +95,15 @@ async fn async_read_nested_or<R: AsyncRead + Unpin>(r: &mut R, do_it: bool) -> R
     Ok(buf)
 }
 
+use tokio::io::{AsyncRead as TokioAsyncRead, AsyncReadExt as _, AsyncWrite as TokioAsyncWrite, AsyncWriteExt as _};
+
+async fn bad_async_write_tokio<W: TokioAsyncWrite + Unpin>(w: &mut W) {
+    w.write(b"hello world").await.unwrap();
+}
+
+async fn bad_async_read_tokio<R: TokioAsyncRead + Unpin>(r: &mut R) {
+    let mut buf = [0u8; 0];
+    r.read(&mut buf[..]).await.unwrap();
+}
+
 fn main() {}

tests/ui/unused_io_amount.stderr

@@ -77,16 +77,28 @@ LL |     r.read(&mut buf[..]).await.unwrap();
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: written amount is not handled. Use `AsyncWriteExt::write_all` instead
-  --> $DIR/unused_io_amount.rs:86:9
+  --> $DIR/unused_io_amount.rs:85:9
    |
 LL |         w.write(b"hello world").await?;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: read amount is not handled. Use `AsyncReadExt::read_exact` instead
-  --> $DIR/unused_io_amount.rs:94:9
+  --> $DIR/unused_io_amount.rs:93:9
    |
 LL |         r.read(&mut buf[..]).await.or(Err(Error::Kind))?;
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to 14 previous errors
+error: written amount is not handled. Use `AsyncWriteExt::write_all` instead
+  --> $DIR/unused_io_amount.rs:101:5
+   |
+LL |     w.write(b"hello world").await.unwrap();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: read amount is not handled. Use `AsyncReadExt::read_exact` instead
+  --> $DIR/unused_io_amount.rs:106:5
+   |
+LL |     r.read(&mut buf[..]).await.unwrap();
+   |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 16 previous errors