From c33291b244cd17e3720cac0d173ffdb316847d83 Mon Sep 17 00:00:00 2001
From: Harris Kaufmann <st4ck0v3rfl0w@gmail.com>
Date: Sun, 3 Aug 2025 00:02:50 +0200
Subject: [PATCH 1/3] der: add `new` and derives to SequenceRef

---
 der/src/asn1/sequence.rs | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/der/src/asn1/sequence.rs b/der/src/asn1/sequence.rs
index 9b7c8a70b..2013a5660 100644
--- a/der/src/asn1/sequence.rs
+++ b/der/src/asn1/sequence.rs
@@ -2,8 +2,8 @@
 //! `SEQUENCE`s to Rust structs.
 
 use crate::{
-    BytesRef, DecodeValue, EncodeValue, Error, FixedTag, Header, Length, Reader, Result, Tag,
-    Writer,
+    BytesRef, DecodeValue, EncodeValue, Error, ErrorKind, FixedTag, Header, Length, Reader, Result,
+    Tag, Writer,
 };
 
 #[cfg(feature = "alloc")]
@@ -28,12 +28,20 @@ impl<'a, T> Sequence<'a> for Box<T> where T: Sequence<'a> {}
 /// DER-encoded `SEQUENCE`.
 ///
 /// This is a zero-copy reference type which borrows from the input data.
+#[derive(Copy, Clone, Debug, Eq, PartialEq, PartialOrd, Ord)]
 pub struct SequenceRef<'a> {
     /// Body of the `SEQUENCE`.
     body: &'a BytesRef,
 }
 
 impl<'a> SequenceRef<'a> {
+    /// Create a new [`SequenceRef`] from the provided DER bytes.
+    pub fn new(slice: &'a [u8]) -> Result<Self> {
+        BytesRef::new(slice)
+            .map(|body| Self { body })
+            .map_err(|_| ErrorKind::Length { tag: Self::TAG }.into())
+    }
+
     /// Borrow the inner byte slice.
     pub fn as_bytes(&self) -> &'a [u8] {
         self.body.as_slice()

From 3ac2a6b218f4255c5bbbeb831f1ff7c203721643 Mon Sep 17 00:00:00 2001
From: dishmaker <141624503+dishmaker@users.noreply.github.com>
Date: Fri, 22 Aug 2025 13:31:06 +0200
Subject: [PATCH 2/3] der: add test for derive Sequence with IMPLICIT
 SequenceRef

---
 der/tests/derive.rs | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/der/tests/derive.rs b/der/tests/derive.rs
index b94748b26..def6d7c52 100644
--- a/der/tests/derive.rs
+++ b/der/tests/derive.rs
@@ -278,7 +278,7 @@ mod sequence {
     use core::marker::PhantomData;
     use der::{
         Decode, Encode, Sequence, ValueOrd,
-        asn1::{AnyRef, ObjectIdentifier, SetOf},
+        asn1::{AnyRef, ObjectIdentifier, SequenceRef, SetOf},
     };
     use hex_literal::hex;
 
@@ -723,6 +723,28 @@ mod sequence {
             algorithm_identifier.to_der().unwrap()
         );
     }
+
+    #[derive(Debug, Sequence)]
+    pub struct OidAndImplicitSequence<'a> {
+        pub oid: ObjectIdentifier,
+        #[asn1(context_specific = "0", tag_mode = "IMPLICIT")]
+        pub data: SequenceRef<'a>,
+    }
+
+    #[test]
+    fn roundtrip_oid_and_implicit_sequence() {
+        let obj_data: &[u8] = &hex!(
+            "30 09" // SEQUENCE
+                "06 03" // OBJECT IDENTIFIER
+                    "29 01 01" // oid "1.1.1.1"
+                "A0 02" // CONTEXT-SPECIFIC [0] (constructed)
+                    "AA BB"
+        );
+        let obj = OidAndImplicitSequence::from_der(obj_data).unwrap();
+
+        assert_eq!(obj.data.as_bytes(), &hex!("AA BB"));
+        assert_eq!(obj_data, &obj.to_der().unwrap());
+    }
 }
 
 /// Custom derive test cases for the `EncodeValue` macro.

From 88ebffbd976e0bb4f3e5e72c414e2b962ba2d125 Mon Sep 17 00:00:00 2001
From: dishmaker <141624503+dishmaker@users.noreply.github.com>
Date: Sun, 24 Aug 2025 12:52:27 +0200
Subject: [PATCH 3/3] der: docs: SequenceRef::new

---
 der/src/asn1/sequence.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/der/src/asn1/sequence.rs b/der/src/asn1/sequence.rs
index 2013a5660..62d160d02 100644
--- a/der/src/asn1/sequence.rs
+++ b/der/src/asn1/sequence.rs
@@ -35,7 +35,7 @@ pub struct SequenceRef<'a> {
 }
 
 impl<'a> SequenceRef<'a> {
-    /// Create a new [`SequenceRef`] from the provided DER bytes.
+    /// Create a new [`SequenceRef`] from the DER bytes of the inner value.
     pub fn new(slice: &'a [u8]) -> Result<Self> {
         BytesRef::new(slice)
             .map(|body| Self { body })