style: misc clippy fixes

uefi/src/helpers/logger.rs

@@ -248,7 +248,7 @@ impl<W: fmt::Write> fmt::Write for DecoratedLog<'_, '_, W> {
         // If the string ends with a newline character, we must 1/propagate it
         // to the output (it was swallowed by the iteration) and 2/prepare to
         // write the log level of the beginning of the next line (if any).
-        if let Some('\n') = s.chars().next_back() {
+        if s.ends_with('\n') {
             writeln!(self.writer)?;
             self.at_line_start = true;
         }

uefi/src/proto/media/file/dir.rs

@@ -69,7 +69,7 @@ impl Directory {
         let read_entry_res = self.read_entry(&mut []);
 
         // If no more entries are available, return early.
-        if let Ok(None) = read_entry_res {
+        if read_entry_res == Ok(None) {
             return Ok(None);
         }
 
@@ -102,7 +102,7 @@ impl Directory {
         let read_entry_res = self.read_entry(&mut []);
 
         // If no more entries are available, return early.
-        if let Ok(None) = read_entry_res {
+        if read_entry_res == Ok(None) {
             return Ok(None);
         }
 

uefi/src/proto/tcg/v1.rs

@@ -429,14 +429,13 @@ impl Tcg {
         data_to_hash: Option<&[u8]>,
     ) -> Result {
         let hash_data;
-        let hash_data_len;
-        if let Some(data_to_hash) = data_to_hash {
+        let hash_data_len = if let Some(data_to_hash) = data_to_hash {
             hash_data = data_to_hash.as_ptr() as PhysicalAddress;
-            hash_data_len = u64::try_from(data_to_hash.len()).unwrap();
+            u64::try_from(data_to_hash.len()).unwrap()
         } else {
             hash_data = 0;
-            hash_data_len = 0;
-        }
+            0
+        };
 
         // Don't bother returning these, it's not very useful info.
         let mut event_number = 0;

uefi/src/runtime.rs

@@ -321,14 +321,13 @@ impl Iterator for VariableKeys {
                 }))
             }
             Err(err) => {
+                self.is_done = true;
                 if err.status() == Status::NOT_FOUND {
                     // This status indicates the end of the list. The final variable
                     // has already been yielded at this point, so return `None`.
-                    self.is_done = true;
                     None
                 } else {
                     // Return the error and end iteration.
-                    self.is_done = true;
                     Some(Err(err.to_err_without_payload()))
                 }
             }