diff --git a/src/decoder.rs b/src/decoder.rs
index 12eb930..d615848 100644
--- a/src/decoder.rs
+++ b/src/decoder.rs
@@ -120,7 +120,7 @@ impl<'a> Decoder<'a> {
     pub(crate) fn peek(&self) -> Option<u8> {
         self.remaining()
             .ok()
-            .and_then(|bytes| bytes.get(0).cloned())
+            .and_then(|bytes| bytes.first().cloned())
     }
 
     /// Obtain the remaining bytes in this decoder from the current cursor
diff --git a/src/length.rs b/src/length.rs
index 28c20c6..8ae099a 100644
--- a/src/length.rs
+++ b/src/length.rs
@@ -38,7 +38,7 @@ impl<'a> TryFrom<&'a [&'a dyn Encodable]> for Length {
     fn try_from(encodables: &[&dyn Encodable]) -> Result<Length> {
         encodables
             .iter()
-            .fold(Ok(Length::zero()), |sum, encodable| {
+            .try_fold(Length::zero(), |sum, encodable| {
                 sum + encodable.encoded_length()?
             })
     }
diff --git a/src/tag.rs b/src/tag.rs
index 1533b16..c64656f 100644
--- a/src/tag.rs
+++ b/src/tag.rs
@@ -209,10 +209,7 @@ impl Encodable for Tag {
                 encoder.byte(NOT_LAST_TAG_OCTET_FLAG | (self.number >> 7) as u8)?;
                 encoder.byte((self.number & 0x7F) as u8)
             }
-            0x4000..=0xFFFF => {
-                // todo()
-                return Err(Error::from(ErrorKind::UnsupportedTagSize));
-            }
+            0x4000..=0xFFFF => Err(Error::from(ErrorKind::UnsupportedTagSize)),
         }
     }
 }
diff --git a/src/tagged.rs b/src/tagged.rs
index d7daba4..beea658 100644
--- a/src/tagged.rs
+++ b/src/tagged.rs
@@ -29,7 +29,7 @@ where
     }
 }
 
-impl<'a, E, T> TaggedValue<&'a E, T>
+impl<E, T> TaggedValue<&'_ E, T>
 where
     E: Encodable,
     T: Copy + Encodable,
@@ -42,7 +42,7 @@ where
     }
 }
 
-impl<'a, E, T> Encodable for TaggedValue<&'a E, T>
+impl<E, T> Encodable for TaggedValue<&E, T>
 where
     E: Encodable,
     T: Copy + Encodable,
@@ -119,7 +119,7 @@ where
     }
 }
 
-impl<'a, T> Encodable for TaggedSlice<'a, T>
+impl<T> Encodable for TaggedSlice<'_, T>
 where
     T: Copy + Encodable,
 {
diff --git a/src/traits.rs b/src/traits.rs
index 7c2f085..dcf11f8 100644
--- a/src/traits.rs
+++ b/src/traits.rs
@@ -1,9 +1,7 @@
 // pub use der::{Decodable, Encodable};
 //! Trait definitions
 
-use crate::{
-    header::Header, Decoder, Encoder, Error, Length, Result, Tag, TagLike, TaggedSlice, TaggedValue,
-};
+use crate::{header::Header, Decoder, Encoder, Error, Length, Result, Tag, TaggedSlice};
 use core::convert::{TryFrom, TryInto};
 
 #[cfg(feature = "alloc")]
@@ -164,20 +162,6 @@ pub trait EncodableHeapless: Encodable {
 #[cfg(feature = "heapless")]
 impl<X> EncodableHeapless for X where X: Encodable {}
 
-/// Types that can be tagged.
-pub(crate) trait Taggable<T: TagLike>: Sized {
-    fn tagged(&self, tag: T) -> TaggedValue<&Self, T> {
-        TaggedValue::new(tag, self)
-    }
-}
-
-impl<T, X> Taggable<T> for X
-where
-    X: Sized,
-    T: TagLike,
-{
-}
-
 // /// Types with an associated BER-TLV [`Tag`].
 // pub trait Tagged {
 //     /// BER-TLV tag
@@ -354,10 +338,24 @@ impl_array!(
 #[cfg(test)]
 mod tests {
 
-    use super::{Container, Taggable, Tagged};
-    use crate::{Decodable, Encodable, Error, Result, Tag, TagLike, TaggedSlice};
+    use super::{Container, Tagged};
+    use crate::{Decodable, Encodable, Error, Result, Tag, TagLike, TaggedSlice, TaggedValue};
     use core::convert::TryFrom;
 
+    /// Types that can be tagged.
+    pub(crate) trait Taggable<T: TagLike>: Sized {
+        fn tagged(&self, tag: T) -> TaggedValue<&Self, T> {
+            TaggedValue::new(tag, self)
+        }
+    }
+
+    impl<T, X> Taggable<T> for X
+    where
+        X: Sized,
+        T: TagLike,
+    {
+    }
+
     // The types [u8; 2], [u8; 3], [u8; 4] stand in here for any types for the fields
     // of a struct that are Decodable + Encodable. This means they can decode to/encode from
     // a byte slice, but also that thye can declare their encoded length.
@@ -578,13 +576,13 @@ mod tests {
     }
 
     // no tag
-    #[derive(Clone, Copy, Debug, Eq, PartialEq)]
-    struct T3 {
-        // no tag
-        s: S,
-        // tag 0x02
-        t: [u8; 3],
-    }
+    // #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+    // struct T3 {
+    //     // no tag
+    //     s: S,
+    //     // tag 0x02
+    //     t: [u8; 3],
+    // }
 
     // impl<'a> TryFrom<TaggedSlice<'a>> for T2 {
     //     type Error = Error;
@@ -655,7 +653,7 @@ mod tests {
         };
         let encoded = s.encode_to_slice(&mut buf).unwrap();
 
-        let mut decoder = crate::Decoder::new(&encoded);
+        let mut decoder = crate::Decoder::new(encoded);
         let s: Option<S> = decoder.decode().unwrap();
         assert!(s.is_some());