diff --git a/crates/neon/src/context/mod.rs b/crates/neon/src/context/mod.rs
index 98b9b8bf5..1c4ae2aa3 100644
--- a/crates/neon/src/context/mod.rs
+++ b/crates/neon/src/context/mod.rs
@@ -375,7 +375,7 @@ pub trait Context<'a>: ContextInternal<'a> {
     /// Lock the JavaScript engine, returning an RAII guard that keeps the lock active as long as the guard is alive.
     ///
     /// If this is not the currently active context (for example, if it was used to spawn a scoped context with `execute_scoped` or `compute_scoped`), this method will panic.
-    fn lock<'b>(&'b mut self) -> Lock<Self>
+    fn lock<'b>(&'b mut self) -> Lock<'b, Self>
     where
         'a: 'b,
     {
@@ -641,7 +641,7 @@ pub trait Context<'a>: ContextInternal<'a> {
     ///     Ok(promise)
     /// }
     /// ```
-    fn task<'cx, O, E>(&'cx mut self, execute: E) -> TaskBuilder<Self, E>
+    fn task<'cx, O, E>(&'cx mut self, execute: E) -> TaskBuilder<'cx, Self, E>
     where
         'a: 'cx,
         O: Send + 'static,
diff --git a/crates/neon/src/event/channel.rs b/crates/neon/src/event/channel.rs
index 860292bc6..cc2872f29 100644
--- a/crates/neon/src/event/channel.rs
+++ b/crates/neon/src/event/channel.rs
@@ -1,5 +1,5 @@
 use std::{
-    error, fmt, mem,
+    error, fmt,
     sync::{
         atomic::{AtomicUsize, Ordering},
         Arc,
@@ -7,9 +7,9 @@ use std::{
 };
 
 use crate::{
-    context::{Context, Cx},
+    context::{internal::Env, Context, Cx},
     result::{NeonResult, ResultExt, Throw},
-    sys::{raw::Env, tsfn::ThreadsafeFunction},
+    sys::{self, tsfn::ThreadsafeFunction},
 };
 
 #[cfg(feature = "futures")]
@@ -44,7 +44,7 @@ mod oneshot {
     }
 }
 
-type Callback = Box<dyn FnOnce(Env) + Send + 'static>;
+type Callback = Box<dyn FnOnce(sys::Env) + Send + 'static>;
 
 /// Channel for scheduling Rust closures to execute on the JavaScript main thread.
 ///
@@ -159,7 +159,7 @@ impl Channel {
     {
         let (tx, rx) = oneshot::channel();
         let callback = Box::new(move |env| {
-            let env = unsafe { mem::transmute(env) };
+            let env = Env::from(env);
 
             // Note: It is sufficient to use `Cx` because
             // N-API creates a `HandleScope` before calling the callback.
@@ -409,7 +409,7 @@ impl ChannelState {
     }
 
     // Monomorphized trampoline funciton for calling the user provided closure
-    fn callback(env: Option<Env>, callback: Callback) {
+    fn callback(env: Option<sys::Env>, callback: Callback) {
         if let Some(env) = env {
             callback(env);
         } else {
diff --git a/crates/neon/src/handle/mod.rs b/crates/neon/src/handle/mod.rs
index ee6a91a9c..41654b253 100644
--- a/crates/neon/src/handle/mod.rs
+++ b/crates/neon/src/handle/mod.rs
@@ -132,7 +132,7 @@ impl<'a, F: Value, T: Value> ResultExt<Handle<'a, T>> for DowncastResult<'a, F,
     fn or_throw<'b, C: Context<'b>>(self, cx: &mut C) -> JsResult<'a, T> {
         match self {
             Ok(v) => Ok(v),
-            Err(e) => cx.throw_type_error(&e.to_string()),
+            Err(e) => cx.throw_type_error(e.to_string()),
         }
     }
 }
diff --git a/crates/neon/src/lifecycle.rs b/crates/neon/src/lifecycle.rs
index 0a08ef922..807e1e0ce 100644
--- a/crates/neon/src/lifecycle.rs
+++ b/crates/neon/src/lifecycle.rs
@@ -102,7 +102,7 @@ impl LocalCell {
         }
     }
 
-    pub(crate) fn get<'cx, 'a, C>(cx: &'a mut C, id: usize) -> Option<&mut LocalCellValue>
+    pub(crate) fn get<'cx, 'a, C>(cx: &'a mut C, id: usize) -> Option<&'a mut LocalCellValue>
     where
         C: Context<'cx>,
     {
@@ -113,7 +113,11 @@ impl LocalCell {
         }
     }
 
-    pub(crate) fn get_or_init<'cx, 'a, C, F>(cx: &'a mut C, id: usize, f: F) -> &mut LocalCellValue
+    pub(crate) fn get_or_init<'cx, 'a, C, F>(
+        cx: &'a mut C,
+        id: usize,
+        f: F,
+    ) -> &'a mut LocalCellValue
     where
         C: Context<'cx>,
         F: FnOnce() -> LocalCellValue,
@@ -129,7 +133,7 @@ impl LocalCell {
         cx: &'a mut C,
         id: usize,
         f: F,
-    ) -> Result<&mut LocalCellValue, E>
+    ) -> Result<&'a mut LocalCellValue, E>
     where
         C: Context<'cx>,
         F: FnOnce(&mut C) -> Result<LocalCellValue, E>,
diff --git a/crates/neon/src/types_impl/boxed.rs b/crates/neon/src/types_impl/boxed.rs
index 1caf8ae87..ed73fce17 100644
--- a/crates/neon/src/types_impl/boxed.rs
+++ b/crates/neon/src/types_impl/boxed.rs
@@ -242,7 +242,7 @@ impl<T: Finalize + 'static> JsBox<T> {
         // contained value `T`.
         fn finalizer<U: Finalize + 'static>(env: raw::Env, data: BoxAny) {
             let data = *data.downcast::<U>().unwrap();
-            let env = unsafe { std::mem::transmute(env) };
+            let env = Env::from(env);
 
             Cx::with_context(env, move |mut cx| data.finalize(&mut cx));
         }
diff --git a/crates/neon/src/types_impl/extract/json.rs b/crates/neon/src/types_impl/extract/json.rs
index 0dc8930af..ee3659e9b 100644
--- a/crates/neon/src/types_impl/extract/json.rs
+++ b/crates/neon/src/types_impl/extract/json.rs
@@ -34,7 +34,7 @@ fn json_stringify<'cx>(cx: &mut Cx<'cx>) -> JsResult<'cx, JsFunction> {
         .map(|f| f.to_inner(cx))
 }
 
-fn stringify<'cx>(cx: &mut Cx<'cx>, v: Handle<JsValue>) -> NeonResult<String> {
+fn stringify(cx: &mut Cx, v: Handle<JsValue>) -> NeonResult<String> {
     json_stringify(cx)?
         .call(cx, v, [v])?
         .downcast_or_throw::<JsString, _>(cx)
diff --git a/crates/neon/src/types_impl/extract/try_from_js.rs b/crates/neon/src/types_impl/extract/try_from_js.rs
index d7357b224..c34959408 100644
--- a/crates/neon/src/types_impl/extract/try_from_js.rs
+++ b/crates/neon/src/types_impl/extract/try_from_js.rs
@@ -270,7 +270,7 @@ impl<'cx> TryFromJs<'cx> for ArrayBuffer {
     from_js!();
 }
 
-fn is_null_or_undefined<'cx, V>(cx: &mut Cx<'cx>, v: Handle<V>) -> NeonResult<bool>
+fn is_null_or_undefined<V>(cx: &mut Cx, v: Handle<V>) -> NeonResult<bool>
 where
     V: Value,
 {
diff --git a/crates/neon/src/types_impl/mod.rs b/crates/neon/src/types_impl/mod.rs
index 3f8677e51..45837cfb3 100644
--- a/crates/neon/src/types_impl/mod.rs
+++ b/crates/neon/src/types_impl/mod.rs
@@ -451,7 +451,7 @@ impl<'a> ResultExt<Handle<'a, JsString>> for StringResult<'a> {
     fn or_throw<'b, C: Context<'b>>(self, cx: &mut C) -> JsResult<'a, JsString> {
         match self {
             Ok(v) => Ok(v),
-            Err(e) => cx.throw_range_error(&e.to_string()),
+            Err(e) => cx.throw_range_error(e.to_string()),
         }
     }
 }
diff --git a/crates/neon/src/types_impl/utf8.rs b/crates/neon/src/types_impl/utf8.rs
index fe772edf4..20bc97465 100644
--- a/crates/neon/src/types_impl/utf8.rs
+++ b/crates/neon/src/types_impl/utf8.rs
@@ -1,6 +1,6 @@
 use std::borrow::Cow;
 
-const SMALL_MAX: usize = std::i32::MAX as usize;
+const SMALL_MAX: usize = i32::MAX as usize;
 
 /// V8 APIs that take UTF-8 strings take their length in the form of 32-bit
 /// signed integers. This type represents a UTF-8 string that contains no
diff --git a/test/napi/src/js/futures.rs b/test/napi/src/js/futures.rs
index 5d2168674..3c71975bb 100644
--- a/test/napi/src/js/futures.rs
+++ b/test/napi/src/js/futures.rs
@@ -9,7 +9,7 @@ fn runtime<'a, C: Context<'a>>(cx: &mut C) -> NeonResult<&'static Runtime> {
 
     RUNTIME
         .get_or_try_init(Runtime::new)
-        .or_else(|err| cx.throw_error(&err.to_string()))
+        .or_else(|err| cx.throw_error(err.to_string()))
 }
 
 // Accepts two functions that take no parameters and return numbers.
diff --git a/test/napi/src/js/typedarrays.rs b/test/napi/src/js/typedarrays.rs
index bb8312f26..662792c22 100644
--- a/test/napi/src/js/typedarrays.rs
+++ b/test/napi/src/js/typedarrays.rs
@@ -216,7 +216,7 @@ where
     Ok(obj)
 }
 
-fn detach_and_then<'cx, F>(mut cx: FunctionContext<'cx>, f: F) -> JsResult<JsObject>
+fn detach_and_then<'cx, F>(mut cx: FunctionContext<'cx>, f: F) -> JsResult<'cx, JsObject>
 where
     F: FnOnce(
         &mut FunctionContext<'cx>,