diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index af888ff09e..8413e2f8ed 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -84,7 +84,7 @@ jobs:
       - name: Install Rust
         uses: hecrj/setup-rust-action@v1
         with:
-          rust-version: 1.56.1
+          rust-version: 1.57.0
 
       - name: Install clippy and rustfmt
         if: matrix.job == 'lint'
diff --git a/bench_util/src/profiling.rs b/bench_util/src/profiling.rs
index aad9f0159a..b4459ad60a 100644
--- a/bench_util/src/profiling.rs
+++ b/bench_util/src/profiling.rs
@@ -54,7 +54,7 @@ fn run_profile(test: TestDescAndFn) {
       bencher::bench::run_once(|harness| bencher.run(harness));
     }
     StaticBenchFn(benchfn) => {
-      bencher::bench::run_once(|harness| benchfn(harness));
+      bencher::bench::run_once(benchfn);
     }
   };
 }
diff --git a/cli/lsp/mod.rs b/cli/lsp/mod.rs
index 27795e698c..bbfb757dc7 100644
--- a/cli/lsp/mod.rs
+++ b/cli/lsp/mod.rs
@@ -1,5 +1,8 @@
 // Copyright 2018-2021 the Deno authors. All rights reserved. MIT license.
 
+// FIXME(bartlomieju): remove this attribute
+#![allow(unused)]
+
 use deno_core::error::AnyError;
 use lspower::LspService;
 use lspower::Server;
diff --git a/cli/tools/installer.rs b/cli/tools/installer.rs
index a426fea0f2..252939f851 100644
--- a/cli/tools/installer.rs
+++ b/cli/tools/installer.rs
@@ -137,7 +137,7 @@ pub fn infer_name_from_url(url: &Url) -> Option<String> {
       stem = parent_name.to_string_lossy().to_string();
     }
   }
-  let stem = stem.splitn(2, '@').next().unwrap().to_string();
+  let stem = stem.split_once('@').map_or(&*stem, |x| x.0).to_string();
   Some(stem)
 }
 
diff --git a/core/async_cancel.rs b/core/async_cancel.rs
index ab7ec22483..1cdddcdb53 100644
--- a/core/async_cancel.rs
+++ b/core/async_cancel.rs
@@ -511,7 +511,7 @@ mod internal {
       /// the heap allocation that contains the `CancelHandle`. Without this
       /// extra weak reference, `Rc::get_mut()` might succeed and allow the
       /// `CancelHandle` to be moved when it isn't safe to do so.
-      weak_pin: Weak<dyn Any>,
+      _weak_pin: Weak<dyn Any>,
     },
     /// All item nodes in a chain are associated with a `Cancelable` head node.
     Item {
@@ -523,8 +523,8 @@ mod internal {
 
   impl NodeKind {
     fn head(rc_pin: &Rc<dyn Any>) -> Self {
-      let weak_pin = Rc::downgrade(rc_pin);
-      Self::Head { weak_pin }
+      let _weak_pin = Rc::downgrade(rc_pin);
+      Self::Head { _weak_pin }
     }
 
     fn item(waker: &Waker) -> Self {
diff --git a/core/modules.rs b/core/modules.rs
index bc3885a7be..067ee48e37 100644
--- a/core/modules.rs
+++ b/core/modules.rs
@@ -1487,7 +1487,7 @@ mod tests {
 
   #[test]
   fn slow_never_ready_modules() {
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let loader = MockLoader::new();
       let loads = loader.loads.clone();
       let mut runtime = JsRuntime::new(RuntimeOptions {
@@ -1498,7 +1498,7 @@ mod tests {
       let mut recursive_load =
         runtime.load_main_module(&spec, None).boxed_local();
 
-      let result = recursive_load.poll_unpin(&mut cx);
+      let result = recursive_load.poll_unpin(cx);
       assert!(result.is_pending());
 
       // TODO(ry) Arguably the first time we poll only the following modules
@@ -1511,7 +1511,7 @@ mod tests {
       // run_in_task.
 
       for _ in 0..10 {
-        let result = recursive_load.poll_unpin(&mut cx);
+        let result = recursive_load.poll_unpin(cx);
         assert!(result.is_pending());
         let l = loads.lock();
         assert_eq!(
@@ -1537,7 +1537,7 @@ mod tests {
 
   #[test]
   fn loader_disappears_after_error() {
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let loader = MockLoader::new();
       let mut runtime = JsRuntime::new(RuntimeOptions {
         module_loader: Some(loader),
@@ -1545,7 +1545,7 @@ mod tests {
       });
       let spec = crate::resolve_url("file:///bad_import.js").unwrap();
       let mut load_fut = runtime.load_main_module(&spec, None).boxed_local();
-      let result = load_fut.poll_unpin(&mut cx);
+      let result = load_fut.poll_unpin(cx);
       if let Poll::Ready(Err(err)) = result {
         assert_eq!(
           err.downcast_ref::<MockError>().unwrap(),
diff --git a/core/runtime.rs b/core/runtime.rs
index 5db11d9c5a..15bb103ba1 100644
--- a/core/runtime.rs
+++ b/core/runtime.rs
@@ -1950,7 +1950,7 @@ pub mod tests {
 
   #[test]
   fn test_pre_dispatch() {
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let (mut runtime, _dispatch_count) = setup(Mode::Async);
       runtime
         .execute_script(
@@ -1966,7 +1966,7 @@ pub mod tests {
          "#,
         )
         .unwrap();
-      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(&mut cx, false) {
+      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(cx, false) {
         unreachable!();
       }
     });
@@ -1984,7 +1984,7 @@ pub mod tests {
 
   #[test]
   fn test_encode_decode() {
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let (mut runtime, _dispatch_count) = setup(Mode::Async);
       runtime
         .execute_script(
@@ -1992,7 +1992,7 @@ pub mod tests {
           include_str!("encode_decode_test.js"),
         )
         .unwrap();
-      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(&mut cx, false) {
+      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(cx, false) {
         unreachable!();
       }
     });
@@ -2000,7 +2000,7 @@ pub mod tests {
 
   #[test]
   fn test_serialize_deserialize() {
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let (mut runtime, _dispatch_count) = setup(Mode::Async);
       runtime
         .execute_script(
@@ -2008,7 +2008,7 @@ pub mod tests {
           include_str!("serialize_deserialize_test.js"),
         )
         .unwrap();
-      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(&mut cx, false) {
+      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(cx, false) {
         unreachable!();
       }
     });
@@ -2024,7 +2024,7 @@ pub mod tests {
       "DOMExceptionOperationError"
     }
 
-    run_in_task(|mut cx| {
+    run_in_task(|cx| {
       let mut runtime = JsRuntime::new(RuntimeOptions {
         get_error_class_fn: Some(&get_error_class_name),
         ..Default::default()
@@ -2037,7 +2037,7 @@ pub mod tests {
           include_str!("error_builder_test.js"),
         )
         .unwrap();
-      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(&mut cx, false) {
+      if let Poll::Ready(Err(_)) = runtime.poll_event_loop(cx, false) {
         unreachable!();
       }
     });
diff --git a/ext/net/ops_tls.rs b/ext/net/ops_tls.rs
index 67e6dfc167..3de5d84766 100644
--- a/ext/net/ops_tls.rs
+++ b/ext/net/ops_tls.rs
@@ -665,7 +665,7 @@ impl Shared {
       self_arc.rd_waker.wake();
       self_arc.wr_waker.wake();
     }
-    self_weak.into_raw();
+    let _ = self_weak.into_raw();
   }
 
   fn drop_shared_waker(self_ptr: *const ()) {
diff --git a/runtime/ops/permissions.rs b/runtime/ops/permissions.rs
index 05f4b75d7c..d8005a743e 100644
--- a/runtime/ops/permissions.rs
+++ b/runtime/ops/permissions.rs
@@ -38,8 +38,8 @@ pub fn op_query_permission(
   let permissions = state.borrow::<Permissions>();
   let path = args.path.as_deref();
   let perm = match args.name.as_ref() {
-    "read" => permissions.read.query(path.as_deref().map(Path::new)),
-    "write" => permissions.write.query(path.as_deref().map(Path::new)),
+    "read" => permissions.read.query(path.map(Path::new)),
+    "write" => permissions.write.query(path.map(Path::new)),
     "net" => permissions.net.query(
       match args.host.as_deref() {
         None => None,
@@ -69,8 +69,8 @@ pub fn op_revoke_permission(
   let permissions = state.borrow_mut::<Permissions>();
   let path = args.path.as_deref();
   let perm = match args.name.as_ref() {
-    "read" => permissions.read.revoke(path.as_deref().map(Path::new)),
-    "write" => permissions.write.revoke(path.as_deref().map(Path::new)),
+    "read" => permissions.read.revoke(path.map(Path::new)),
+    "write" => permissions.write.revoke(path.map(Path::new)),
     "net" => permissions.net.revoke(
       match args.host.as_deref() {
         None => None,
@@ -100,8 +100,8 @@ pub fn op_request_permission(
   let permissions = state.borrow_mut::<Permissions>();
   let path = args.path.as_deref();
   let perm = match args.name.as_ref() {
-    "read" => permissions.read.request(path.as_deref().map(Path::new)),
-    "write" => permissions.write.request(path.as_deref().map(Path::new)),
+    "read" => permissions.read.request(path.map(Path::new)),
+    "write" => permissions.write.request(path.map(Path::new)),
     "net" => permissions.net.request(
       match args.host.as_deref() {
         None => None,
diff --git a/serde_v8/examples/basic.rs b/serde_v8/examples/basic.rs
index 8bea43bb50..ee5e28fe6a 100644
--- a/serde_v8/examples/basic.rs
+++ b/serde_v8/examples/basic.rs
@@ -34,7 +34,10 @@ fn main() {
 
     let v = exec(scope, "({a: 1, b: 3, c: 'ignored'})");
     let mop: MathOp = serde_v8::from_v8(scope, v).unwrap();
-    println!("mop = {:?}", mop);
+    println!(
+      "mop = {{ a: {}, b: {}, operator: {:?} }}",
+      mop.a, mop.b, mop.operator
+    );
 
     let v = exec(scope, "[1,2,3,4,5]");
     let arr: Vec<u64> = serde_v8::from_v8(scope, v).unwrap();
diff --git a/serde_v8/src/de.rs b/serde_v8/src/de.rs
index f803ab3812..44f94b2d6e 100644
--- a/serde_v8/src/de.rs
+++ b/serde_v8/src/de.rs
@@ -165,14 +165,14 @@ impl<'de, 'a, 'b, 's, 'x> de::Deserializer<'de>
   where
     V: Visitor<'de>,
   {
-    visitor.visit_f32(self.input.number_value(&mut self.scope).unwrap() as f32)
+    visitor.visit_f32(self.input.number_value(self.scope).unwrap() as f32)
   }
 
   fn deserialize_f64<V>(self, visitor: V) -> Result<V::Value>
   where
     V: Visitor<'de>,
   {
-    visitor.visit_f64(self.input.number_value(&mut self.scope).unwrap())
+    visitor.visit_f64(self.input.number_value(self.scope).unwrap())
   }
 
   wip!(deserialize_char);