diff --git a/sentry-core/Cargo.toml b/sentry-core/Cargo.toml
index 59c2200c..c3c3a809 100644
--- a/sentry-core/Cargo.toml
+++ b/sentry-core/Cargo.toml
@@ -38,5 +38,4 @@ log_ = { package = "log", version = "0.4.8", optional = true, features = ["std"]
 sentry = { version = "0.21.0", path = "../sentry", default-features = false, features = ["test"] }
 thiserror = "1.0.15"
 anyhow = "1.0.30"
-failure = "0.1.8"
 tokio = { version = "0.2", features = ["rt-core", "macros"] }
diff --git a/sentry-core/src/error.rs b/sentry-core/src/error.rs
index 980d09ad..4ee16db1 100644
--- a/sentry-core/src/error.rs
+++ b/sentry-core/src/error.rs
@@ -145,11 +145,4 @@ fn test_parse_type_from_debug() {
         anyhow::Error::from("NaN".parse::<usize>().unwrap_err())
     );
     assert_eq!(parse(&err), "ParseIntError");
-
-    // `failure` is using normal debug formatting
-    let err = format!(
-        "{:?}",
-        failure::Error::from("NaN".parse::<usize>().unwrap_err())
-    );
-    assert_eq!(parse(&err), "ParseIntError");
 }
diff --git a/sentry-core/src/scope/real.rs b/sentry-core/src/scope/real.rs
index 3080f91c..23df110e 100644
--- a/sentry-core/src/scope/real.rs
+++ b/sentry-core/src/scope/real.rs
@@ -34,8 +34,8 @@ pub type EventProcessor = Box<dyn Fn(Event<'static>) -> Option<Event<'static>> +
 #[derive(Clone)]
 pub struct Scope {
     pub(crate) level: Option<Level>,
-    pub(crate) fingerprint: Option<Arc<Vec<Cow<'static, str>>>>,
-    pub(crate) transaction: Option<Arc<String>>,
+    pub(crate) fingerprint: Option<Arc<[Cow<'static, str>]>>,
+    pub(crate) transaction: Option<Arc<str>>,
     pub(crate) breadcrumbs: im::Vector<Breadcrumb>,
     pub(crate) user: Option<Arc<User>>,
     pub(crate) extra: im::HashMap<String, Value>,
@@ -167,13 +167,13 @@ impl Scope {
 
     /// Sets the fingerprint.
     pub fn set_fingerprint(&mut self, fingerprint: Option<&[&str]>) {
-        self.fingerprint = fingerprint
-            .map(|fp| Arc::new(fp.iter().map(|x| Cow::Owned((*x).to_string())).collect()))
+        self.fingerprint =
+            fingerprint.map(|fp| fp.iter().map(|s| Cow::Owned((*s).into())).collect())
     }
 
     /// Sets the transaction.
     pub fn set_transaction(&mut self, transaction: Option<&str>) {
-        self.transaction = transaction.map(|txn| Arc::new(txn.to_string()));
+        self.transaction = transaction.map(Arc::from);
     }
 
     /// Sets the user for the current scope.
@@ -231,8 +231,8 @@ impl Scope {
         }
 
         if event.user.is_none() {
-            if let Some(ref user) = self.user {
-                event.user = Some((**user).clone());
+            if let Some(user) = self.user.as_deref() {
+                event.user = Some(user.clone());
             }
         }
 
@@ -244,16 +244,16 @@ impl Scope {
         event.contexts.extend(self.contexts.clone().into_iter());
 
         if event.transaction.is_none() {
-            if let Some(ref txn) = self.transaction {
-                event.transaction = Some((**txn).clone());
+            if let Some(txn) = self.transaction.as_deref() {
+                event.transaction = Some(txn.to_owned());
             }
         }
 
         if event.fingerprint.len() == 1
             && (event.fingerprint[0] == "{{ default }}" || event.fingerprint[0] == "{{default}}")
         {
-            if let Some(ref fp) = self.fingerprint {
-                event.fingerprint = Cow::Owned((**fp).clone());
+            if let Some(fp) = self.fingerprint.as_deref() {
+                event.fingerprint = Cow::Owned(fp.to_owned());
             }
         }
 
diff --git a/sentry-types/src/dsn.rs b/sentry-types/src/dsn.rs
index 16167a40..e67aa5e5 100644
--- a/sentry-types/src/dsn.rs
+++ b/sentry-types/src/dsn.rs
@@ -174,7 +174,7 @@ impl FromStr for Dsn {
 
         let project_id = path_segments
             .next()
-            .ok_or_else(|| ParseDsnError::NoProjectId)?
+            .ok_or(ParseDsnError::NoProjectId)?
             .parse()
             .map_err(ParseDsnError::InvalidProjectId)?;
         let path = match path_segments.next().unwrap_or("") {
diff --git a/sentry/src/defaults.rs b/sentry/src/defaults.rs
index c58bd18d..0a8fbaca 100644
--- a/sentry/src/defaults.rs
+++ b/sentry/src/defaults.rs
@@ -1,6 +1,3 @@
-#![cfg_attr(feature = "error-chain", allow(deprecated))]
-#![cfg_attr(feature = "failure", allow(deprecated))]
-
 use std::env;
 use std::{borrow::Cow, sync::Arc};
 
diff --git a/sentry/src/lib.rs b/sentry/src/lib.rs
index 534144f6..cdf56b6b 100644
--- a/sentry/src/lib.rs
+++ b/sentry/src/lib.rs
@@ -56,8 +56,6 @@
 //!
 //! * `anyhow`: Enables support for the `anyhow` crate.
 //! * `debug-images`: Attaches a list of loaded libraries to events (currently only supported on unix).
-//! * `error-chain`: Enables support for the `error-chain` crate.
-//! * `failure`: Enables support for the `failure` crate.
 //! * `log`: Enables support for the `log` crate.
 //! * `env_logger`: Enables support for the `log` crate with additional `env_logger` support.
 //! * `slog`: Enables support for the `slog` crate.