diff --git a/lib/src/lib.rs b/lib/src/lib.rs
index 4f83aaf0d..58ab5e6b1 100644
--- a/lib/src/lib.rs
+++ b/lib/src/lib.rs
@@ -7,6 +7,11 @@
 // docstrings for extern "C" functions are reflected into C, and do not benefit
 // from safety docs.
 #![allow(clippy::missing_safety_doc)]
+// deny some things that are typically warnings
+#![deny(clippy::derivable_impls)]
+#![deny(clippy::wrong_self_convention)]
+#![deny(clippy::extra_unused_lifetimes)]
+#![deny(clippy::unnecessary_to_owned)]
 
 mod traits;
 mod util;
diff --git a/lib/src/replica.rs b/lib/src/replica.rs
index 11fd26186..cec26ad42 100644
--- a/lib/src/replica.rs
+++ b/lib/src/replica.rs
@@ -149,7 +149,7 @@ pub unsafe extern "C" fn tc_replica_new_on_disk(
             //  - caller will not use path after this call (convention)
             let mut path = unsafe { TCString::val_from_arg(path) };
             let storage = StorageConfig::OnDisk {
-                taskdb_dir: path.to_path_buf()?,
+                taskdb_dir: path.to_path_buf_mut()?,
             }
             .into_storage()?;
 
diff --git a/lib/src/server.rs b/lib/src/server.rs
index b7247bdb6..dc1160d0c 100644
--- a/lib/src/server.rs
+++ b/lib/src/server.rs
@@ -72,7 +72,7 @@ pub unsafe extern "C" fn tc_server_new_local(
             //  - caller will not use server_dir after this call (convention)
             let mut server_dir = unsafe { TCString::val_from_arg(server_dir) };
             let server_config = ServerConfig::Local {
-                server_dir: server_dir.to_path_buf()?,
+                server_dir: server_dir.to_path_buf_mut()?,
             };
             let server = server_config.into_server()?;
             // SAFETY: caller promises to free this server.
diff --git a/lib/src/string.rs b/lib/src/string.rs
index 86b1ac3bd..719a30563 100644
--- a/lib/src/string.rs
+++ b/lib/src/string.rs
@@ -292,7 +292,7 @@ impl<'a> RustString<'a> {
         }
     }
 
-    pub(crate) fn to_path_buf(&mut self) -> Result<PathBuf, std::str::Utf8Error> {
+    pub(crate) fn to_path_buf_mut(&mut self) -> Result<PathBuf, std::str::Utf8Error> {
         #[cfg(unix)]
         let path: OsString = {
             // on UNIX, we can use the bytes directly, without requiring that they
diff --git a/lib/src/task.rs b/lib/src/task.rs
index c3c0b896b..159553760 100644
--- a/lib/src/task.rs
+++ b/lib/src/task.rs
@@ -386,7 +386,7 @@ pub unsafe extern "C" fn tc_task_get_annotations(task: *mut TCTask) -> TCAnnotat
 ///
 /// Returns a TCString with NULL ptr field if the UDA does not exist.
 #[no_mangle]
-pub unsafe extern "C" fn tc_task_get_uda<'a>(
+pub unsafe extern "C" fn tc_task_get_uda(
     task: *mut TCTask,
     ns: TCString,
     key: TCString,
@@ -413,7 +413,7 @@ pub unsafe extern "C" fn tc_task_get_uda<'a>(
 ///
 /// Returns NULL if the UDA does not exist.
 #[no_mangle]
-pub unsafe extern "C" fn tc_task_get_legacy_uda<'a>(task: *mut TCTask, key: TCString) -> TCString {
+pub unsafe extern "C" fn tc_task_get_legacy_uda(task: *mut TCTask, key: TCString) -> TCString {
     wrap(task, |task| {
         // SAFETY:
         //  - key is valid (promised by caller)
@@ -708,11 +708,7 @@ pub unsafe extern "C" fn tc_task_set_uda(
     wrap_mut(
         task,
         |task| {
-            task.set_uda(
-                ns.as_str()?.to_string(),
-                key.as_str()?.to_string(),
-                value.as_str()?.to_string(),
-            )?;
+            task.set_uda(ns.as_str()?, key.as_str()?, value.as_str()?.to_string())?;
             Ok(TCResult::Ok)
         },
         TCResult::Error,
@@ -735,7 +731,7 @@ pub unsafe extern "C" fn tc_task_remove_uda(
     wrap_mut(
         task,
         |task| {
-            task.remove_uda(ns.as_str()?.to_string(), key.as_str()?.to_string())?;
+            task.remove_uda(ns.as_str()?, key.as_str()?)?;
             Ok(TCResult::Ok)
         },
         TCResult::Error,
diff --git a/lib/src/uda.rs b/lib/src/uda.rs
index 607d77e27..30607090c 100644
--- a/lib/src/uda.rs
+++ b/lib/src/uda.rs
@@ -3,6 +3,7 @@ use crate::types::*;
 
 /// TCUda contains the details of a UDA.
 #[repr(C)]
+#[derive(Default)]
 pub struct TCUda {
     /// Namespace of the UDA.  For legacy UDAs, this may have a NULL ptr field.
     pub ns: TCString,
@@ -58,16 +59,6 @@ impl PassByValue for TCUda {
     }
 }
 
-impl Default for TCUda {
-    fn default() -> Self {
-        TCUda {
-            ns: TCString::default(),
-            key: TCString::default(),
-            value: TCString::default(),
-        }
-    }
-}
-
 /// TCUdaList represents a list of UDAs.
 ///
 /// The content of this struct must be treated as read-only.
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 3990a4f39..6fd41b2d7 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -9,7 +9,7 @@ use std::path::PathBuf;
 
 pub fn main() -> anyhow::Result<()> {
     let arg = env::args().nth(1);
-    match arg.as_ref().map(|arg| arg.as_str()) {
+    match arg.as_deref() {
         Some("codegen") => codegen(),
         Some(arg) => anyhow::bail!("unknown xtask {}", arg),
         _ => anyhow::bail!("unknown xtask"),