diff --git a/mbedtls/src/pk/mod.rs b/mbedtls/src/pk/mod.rs
index cbbbd1537..2f4efd82f 100644
--- a/mbedtls/src/pk/mod.rs
+++ b/mbedtls/src/pk/mod.rs
@@ -870,7 +870,7 @@ impl Pk {
 
     pub fn write_private_der_vec(&mut self) -> Result<Vec<u8>> {
         crate::private::alloc_vec_repeat(
-            |buf, size| { let _ = &self; unsafe { pk_write_key_der(&mut self.inner, buf, size) } },
+            |buf, size| { unsafe { pk_write_key_der(&mut self.inner, buf, size) } },
             true,
         )
     }
@@ -886,7 +886,7 @@ impl Pk {
     }
 
     pub fn write_private_pem_string(&mut self) -> Result<String> {
-        crate::private::alloc_string_repeat(|buf, size| { let _ = &self; unsafe {
+        crate::private::alloc_string_repeat(|buf, size| { unsafe {
             match pk_write_key_pem(&mut self.inner, buf as _, size) {
                 0 => crate::private::cstr_to_slice(buf as _).len() as _,
                 r => r,
@@ -906,7 +906,7 @@ impl Pk {
 
     pub fn write_public_der_vec(&mut self) -> Result<Vec<u8>> {
         crate::private::alloc_vec_repeat(
-            |buf, size| { let _ = &self; unsafe { pk_write_pubkey_der(&mut self.inner, buf, size) } },
+            |buf, size| { unsafe { pk_write_pubkey_der(&mut self.inner, buf, size) } },
             true,
         )
     }
@@ -922,7 +922,7 @@ impl Pk {
     }
 
     pub fn write_public_pem_string(&mut self) -> Result<String> {
-        crate::private::alloc_string_repeat(|buf, size| { let _ = &self; unsafe {
+        crate::private::alloc_string_repeat(|buf, size| { unsafe {
             match pk_write_pubkey_pem(&mut self.inner, buf as _, size) {
                 0 => crate::private::cstr_to_slice(buf as _).len() as _,
                 r => r,