diff --git a/src/bam/ext.rs b/src/bam/ext.rs
index c02ce1b5b..fdaa891bc 100644
--- a/src/bam/ext.rs
+++ b/src/bam/ext.rs
@@ -313,6 +313,64 @@ pub trait BamRecordExtensions {
     fn seq_len_from_cigar(&self, include_hard_clip: bool) -> usize;
 }
 
+impl IterAlignedBlocks {
+    /// Create a new `IterAlignedBlocks` from its component parts.
+    ///
+    /// This allows constructing an iterator over aligned blocks without needing
+    /// access to a `BamRecordExtensions` instance.
+    ///
+    /// # Arguments
+    ///
+    /// * `pos` - The starting position on the reference sequence
+    /// * `cigar` - The CIGAR operations as a vector
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use rust_htslib::bam::record::Cigar;
+    /// use rust_htslib::bam::ext::IterAlignedBlocks;
+    ///
+    /// let cigar = vec![Cigar::Match(10), Cigar::Del(5), Cigar::Match(20)];
+    /// let iter = IterAlignedBlocks::new(100, cigar);
+    /// ```
+    pub fn new(pos: i64, cigar: Vec<Cigar>) -> Self {
+        Self {
+            pos,
+            cigar_index: 0,
+            cigar,
+        }
+    }
+}
+
+impl IterIntrons {
+    /// Create a new `IterIntrons` from its component parts.
+    ///
+    /// This allows constructing an iterator over introns without needing
+    /// access to a `BamRecordExtensions` instance.
+    ///
+    /// # Arguments
+    ///
+    /// * `pos` - The starting position on the reference sequence
+    /// * `cigar` - The CIGAR operations as a vector
+    ///
+    /// # Example
+    ///
+    /// ```
+    /// use rust_htslib::bam::record::Cigar;
+    /// use rust_htslib::bam::ext::IterIntrons;
+    ///
+    /// let cigar = vec![Cigar::Match(10), Cigar::RefSkip(1000), Cigar::Match(20)];
+    /// let iter = IterIntrons::new(100, cigar);
+    /// ```
+    pub fn new(pos: i64, cigar: Vec<Cigar>) -> Self {
+        Self {
+            pos,
+            cigar_index: 0,
+            cigar,
+        }
+    }
+}
+
 impl BamRecordExtensions for bam::Record {
     fn aligned_blocks(&self) -> IterAlignedBlocks {
         IterAlignedBlocks {
@@ -1022,6 +1080,26 @@ mod tests {
         assert_eq!(introns[1], [44589703, 44592034]);
     }
 
+    #[test]
+    fn test_iter_constructors() {
+        use crate::bam::ext::{IterAlignedBlocks, IterIntrons};
+
+        // Test IterAlignedBlocks constructor
+        let cigar = vec![Cigar::Match(10), Cigar::Del(5), Cigar::Match(20)];
+        let iter = IterAlignedBlocks::new(100, cigar);
+        let blocks: Vec<_> = iter.collect();
+        assert_eq!(blocks.len(), 2);
+        assert_eq!(blocks[0], [100, 110]);
+        assert_eq!(blocks[1], [115, 135]);
+
+        // Test IterIntrons constructor
+        let cigar = vec![Cigar::Match(10), Cigar::RefSkip(1000), Cigar::Match(20)];
+        let iter = IterIntrons::new(100, cigar);
+        let introns: Vec<_> = iter.collect();
+        assert_eq!(introns.len(), 1);
+        assert_eq!(introns[0], [110, 1110]);
+    }
+
     #[test]
     fn test_aligned_pairs() {
         let mut bam = bam::Reader::from_path("./test/test_spliced_reads.bam").unwrap();
diff --git a/src/bam/mod.rs b/src/bam/mod.rs
index 41fe6f134..474c6202c 100644
--- a/src/bam/mod.rs
+++ b/src/bam/mod.rs
@@ -1029,8 +1029,8 @@ impl Read for IndexedReader {
 impl Drop for IndexedReader {
     fn drop(&mut self) {
         unsafe {
-            if self.itr.is_some() {
-                htslib::hts_itr_destroy(self.itr.unwrap());
+            if let Some(itr) = self.itr {
+                htslib::hts_itr_destroy(itr);
             }
             htslib::hts_close(self.htsfile);
         }
diff --git a/src/bcf/buffer.rs b/src/bcf/buffer.rs
index 130e39027..e54a86a54 100644
--- a/src/bcf/buffer.rs
+++ b/src/bcf/buffer.rs
@@ -107,18 +107,16 @@ impl RecordBuffer {
         }
 
         // move overflow from last fill into ringbuffer
-        if self.overflow.is_some() {
-            let pos = self.overflow.as_ref().unwrap().pos() as u64;
+        if let Some(overflow) = self.overflow.take() {
+            let pos = overflow.pos() as u64;
             if pos >= start {
                 if pos <= end {
-                    self.ringbuffer.push_back(self.overflow.take().unwrap());
+                    self.ringbuffer.push_back(overflow);
                     added += 1;
                 } else {
+                    self.overflow = Some(overflow);
                     return Ok((added, deleted));
                 }
-            } else {
-                // discard overflow
-                self.overflow.take();
             }
         }
 
diff --git a/src/tbx/mod.rs b/src/tbx/mod.rs
index 5994c49e3..18ea00bba 100644
--- a/src/tbx/mod.rs
+++ b/src/tbx/mod.rs
@@ -316,8 +316,8 @@ impl Read for Reader {
 impl Drop for Reader {
     fn drop(&mut self) {
         unsafe {
-            if self.itr.is_some() {
-                htslib::hts_itr_destroy(self.itr.unwrap());
+            if let Some(itr) = self.itr {
+                htslib::hts_itr_destroy(itr);
             }
             htslib::tbx_destroy(self.tbx);
             htslib::hts_close(self.hts_file);