diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 70f8d1a2..47f5050d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -2,7 +2,9 @@ name: CI
 
 on:
   push:
-    branches: [master]
+    branches: 
+      - master
+      - rebis-dev
     tags:
       - "v**"
   pull_request:
@@ -47,7 +49,6 @@ jobs:
           - { os: ubuntu-22.04,   rust-version: nightly, target: 'wasm32-unknown-unknown',   publish: true, args: '--no-default-features' , test-args: '--no-run --no-default-features', use_swap: true }
           # Cargo.toml rust-version
           - { os: ubuntu-22.04,   rust-version: "1.85",  target: 'x86_64-unknown-linux-gnu'}
-          # rust versions
           - { os: ubuntu-22.04,   rust-version: beta,    target: 'x86_64-unknown-linux-gnu'}
           - { os: ubuntu-22.04,   rust-version: nightly, target: 'x86_64-unknown-linux-gnu', miri: true, components: "miri"} 
     defaults:
diff --git a/build/instructions_template.rs b/build/instructions_template.rs
index dc2ed9f7..31c329b9 100644
--- a/build/instructions_template.rs
+++ b/build/instructions_template.rs
@@ -1055,7 +1055,7 @@ fn generate_instruction_preface() -> TokenStream {
                             constants.iter().map(|(c, ptr)| {
                                 functor!(
                                     atom!(":"),
-                                    [cell((c.clone())), indexing_code_ptr((*ptr))]
+                                    [cell((*c)), indexing_code_ptr((*ptr))]
                                 )
                             }),
                         )
@@ -3262,14 +3262,14 @@ where
     let disc = match DiscriminantT::from_str(id.to_string().as_str()) {
         Ok(disc) => disc,
         Err(_) => {
-            panic!("can't generate discriminant {}", id);
+            panic!("can't generate discriminant {id}");
         }
     };
 
     match disc.get_str(key) {
         Some(prop) => prop,
         None => {
-            panic!("can't find property {} of discriminant {:?}", key, disc);
+            panic!("can't find property {key} of discriminant {disc:?}");
         }
     }
 }
@@ -3387,7 +3387,7 @@ impl InstructionData {
 
             (name, arity, CountableInference::HasDefault)
         } else {
-            panic!("type ID is: {}", id);
+            panic!("type ID is: {id}");
         };
 
         let v_ident = variant
diff --git a/build/static_string_indexing.rs b/build/static_string_indexing.rs
index bffb5c13..a577a517 100644
--- a/build/static_string_indexing.rs
+++ b/build/static_string_indexing.rs
@@ -126,14 +126,14 @@ pub fn index_static_strings(instruction_rs_path: &std::path::Path) -> TokenStrea
         match file.read_to_string(&mut src) {
             Ok(_) => {}
             Err(e) => {
-                panic!("error reading file: {:?}", e);
+                panic!("error reading file: {e:?}");
             }
         }
 
         let syntax = match syn::parse_file(&src) {
             Ok(s) => s,
             Err(e) => {
-                panic!("parse error: {} in file {:?}", e, path);
+                panic!("parse error: {e} in file {path:?}");
             }
         };
         Ok(syntax)
diff --git a/src/atom_table.rs b/src/atom_table.rs
index 12910753..d7796d73 100644
--- a/src/atom_table.rs
+++ b/src/atom_table.rs
@@ -254,7 +254,7 @@ impl std::ops::Deref for AtomString<'_> {
     fn deref(&self) -> &Self::Target {
         match self {
             Self::Static(reference) => reference,
-            Self::Inlined(inlined) => inlined_to_str(&inlined),
+            Self::Inlined(inlined) => inlined_to_str(inlined),
             Self::Dynamic(guard) => guard.deref(),
         }
     }
diff --git a/src/debray_allocator.rs b/src/debray_allocator.rs
index 3bc96dfc..53c7f206 100644
--- a/src/debray_allocator.rs
+++ b/src/debray_allocator.rs
@@ -251,7 +251,7 @@ impl DebrayAllocator {
             }
         }
 
-        if self.branch_stack.len() > 0 {
+        if !self.branch_stack.is_empty() {
             for var_num in subsumed_hits {
                 self.branch_stack.add_branch_occurrence(var_num);
             }
diff --git a/src/ffi.rs b/src/ffi.rs
index a3015b6d..55bb525b 100644
--- a/src/ffi.rs
+++ b/src/ffi.rs
@@ -324,7 +324,7 @@ impl ForeignFunctionTable {
         let mut pointer_args =
             Self::build_pointer_args(&mut args, &function_impl.args, &mut self.structs)?;
 
-        return unsafe {
+        unsafe {
             macro_rules! call_and_return {
                 ($type:ty) => {{
                     let mut n: Box<u8> = Box::new(0);
@@ -410,7 +410,7 @@ impl ForeignFunctionTable {
                 }
                 _ => unreachable!(),
             }
-        };
+        }
     }
 
     fn read_struct(
diff --git a/src/forms.rs b/src/forms.rs
index 1418b570..26f37b3e 100644
--- a/src/forms.rs
+++ b/src/forms.rs
@@ -372,11 +372,11 @@ pub enum ModuleSource {
 
 impl ModuleSource {
     pub(crate) fn as_functor_stub(&self) -> MachineStub {
-        match self {
-            &ModuleSource::Library(name) => {
+        match *self {
+            ModuleSource::Library(name) => {
                 functor!(atom!("library"), [atom_as_cell(name)])
             }
-            &ModuleSource::File(name) => {
+            ModuleSource::File(name) => {
                 functor!(name)
             }
         }
@@ -627,9 +627,9 @@ impl Default for Number {
 impl fmt::Display for Number {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            Number::Float(fl) => write!(f, "{}", fl),
-            Number::Integer(n) => write!(f, "{}", n),
-            Number::Rational(r) => write!(f, "{}", r),
+            Number::Float(fl) => write!(f, "{fl}"),
+            Number::Integer(n) => write!(f, "{n}"),
+            Number::Rational(r) => write!(f, "{r}"),
             Number::Fixnum(n) => write!(f, "{}", n.get_num()),
         }
     }
diff --git a/src/functor_macro.rs b/src/functor_macro.rs
index ba19f682..591fa185 100644
--- a/src/functor_macro.rs
+++ b/src/functor_macro.rs
@@ -698,9 +698,9 @@ mod tests {
         let functor = variadic_functor(
             atom!("switch_on_constants"),
             1,
-            constants.iter().map(|(c, ptr)| {
-                functor!(atom!(":"), [cell((c.clone())), indexing_code_ptr((*ptr))])
-            }),
+            constants
+                .iter()
+                .map(|(c, ptr)| functor!(atom!(":"), [cell((*c)), indexing_code_ptr((*ptr))])),
         );
 
         heap.truncate(0);
@@ -739,12 +739,12 @@ mod tests {
             ]
         );
 
-        println!("{:?}", stub);
+        println!("{stub:?}");
 
         // now the error form
         let lineless_error_form = functor!(atom!("error"), [functor(stub), functor(culprit)]);
 
-        println!("{:?}", lineless_error_form);
+        println!("{lineless_error_form:?}");
 
         let mut heap = Heap::new();
         let mut functor_writer = Heap::functor_writer(lineless_error_form);
diff --git a/src/heap_print.rs b/src/heap_print.rs
index 9cc3a2d0..57fef895 100644
--- a/src/heap_print.rs
+++ b/src/heap_print.rs
@@ -831,13 +831,13 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
 
         read_heap_cell!(cell,
             (HeapCellValueTag::Lis | HeapCellValueTag::Str, h) => {
-                Some(format!("{}", h))
+                Some(format!("{h}"))
             }
             (HeapCellValueTag::Var | HeapCellValueTag::AttrVar, h) => {
-                Some(format!("_{}", h))
+                Some(format!("_{h}"))
             }
             (HeapCellValueTag::StackVar, h) => {
-                Some(format!("_s_{}", h))
+                Some(format!("_s_{h}"))
             }
             _ => {
                 None
@@ -1002,7 +1002,7 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
     #[inline]
     fn print_ip_addr(&mut self, ip: IpAddr) {
         push_char!(self, '\'');
-        append_str!(self, &format!("{}", ip));
+        append_str!(self, &format!("{ip}"));
         push_char!(self, '\'');
     }
 
@@ -1039,7 +1039,7 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
                     self.print_rational(max_depth, r, *op);
                 }
                 n => {
-                    let output_str = format!("{}", n);
+                    let output_str = format!("{n}");
 
                     push_space_if_amb!(self, &output_str, {
                         append_str!(self, &output_str);
@@ -1086,7 +1086,7 @@ impl<'a, Outputter: HCValueOutputter> HCPrinter<'a, Outputter> {
         match self.op_dir.get(&(atom!("rdiv"), Fixity::In)) {
             Some(op_desc) => {
                 if r.is_int() {
-                    let output_str = format!("{}", r);
+                    let output_str = format!("{r}");
 
                     push_space_if_amb!(self, &output_str, {
                         append_str!(self, &output_str);
diff --git a/src/iterators.rs b/src/iterators.rs
index 5bd51d99..8e2e43dd 100644
--- a/src/iterators.rs
+++ b/src/iterators.rs
@@ -403,7 +403,7 @@ impl<'a> Iterator for ClauseIterator<'a> {
                             self.state_stack
                                 .push(ClauseIteratorState::RemainingBranches(branches, 0));
                         }
-                        &ChunkedTerms::Chunk { ref terms } => {
+                        ChunkedTerms::Chunk { ref terms } => {
                             return Some(ClauseItem::Chunk { terms });
                         }
                     }
diff --git a/src/machine/compile.rs b/src/machine/compile.rs
index 7dcbee14..8e799009 100644
--- a/src/machine/compile.rs
+++ b/src/machine/compile.rs
@@ -133,7 +133,7 @@ fn merge_indices(
             );
 
             retraction_info.push_record(RetractionRecord::AddedIndex(
-                skeleton[clause_index].opt_arg_index_key.clone(),
+                skeleton[clause_index].opt_arg_index_key,
                 clause_loc,
             ));
         } else {
@@ -246,7 +246,7 @@ fn remove_index_from_subsequence(
         // appear anywhere inside an Internal record.
         retraction_info.push_record(RetractionRecord::RemovedIndex(
             index_loc,
-            opt_arg_index_key.clone(),
+            *opt_arg_index_key,
             offset,
         ));
     }
@@ -808,7 +808,7 @@ fn prepend_compiled_clause(
                 skeleton.clauses[0].clause_start = clause_loc + 2;
 
                 retraction_info.push_record(RetractionRecord::AddedIndex(
-                    skeleton.clauses[0].opt_arg_index_key.clone(),
+                    skeleton.clauses[0].opt_arg_index_key,
                     skeleton.clauses[0].clause_start,
                 ));
 
@@ -1070,7 +1070,7 @@ fn append_compiled_clause(
             skeleton.clauses[target_pos].opt_arg_index_key += index_loc - 1;
 
             retraction_info.push_record(RetractionRecord::AddedIndex(
-                skeleton.clauses[target_pos].opt_arg_index_key.clone(),
+                skeleton.clauses[target_pos].opt_arg_index_key,
                 skeleton.clauses[target_pos].clause_start,
             ));
 
diff --git a/src/machine/cycle_detection.rs b/src/machine/cycle_detection.rs
index da125518..a800a9b6 100644
--- a/src/machine/cycle_detection.rs
+++ b/src/machine/cycle_detection.rs
@@ -137,10 +137,7 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
                         let cell = self.heap[h];
                         let arity = cell_as_atom_cell!(self.heap[h]).get_arity();
 
-                        let last_cell_loc = match self.traverse_subterm(h + 1, arity) {
-                            Some(last_cell_loc) => last_cell_loc,
-                            None => return None,
-                        };
+                        let last_cell_loc = self.traverse_subterm(h + 1, arity)?;
 
                         if last_cell_loc == h {
                             if self.backward() {
@@ -171,10 +168,7 @@ impl<'a, const STOP_AT_CYCLES: bool> CycleDetectingIter<'a, STOP_AT_CYCLES> {
                         let mut cell = self.heap[self.current];
                         cell.set_value(self.next);
 
-                        let last_cell_loc = match self.traverse_subterm(self.next as usize, 2) {
-                            Some(last_cell_loc) => last_cell_loc,
-                            None => return None,
-                        };
+                        let last_cell_loc = self.traverse_subterm(self.next as usize, 2)?;
 
                         if self.cycle_detection_active() {
                             for idx in (self.next as usize..last_cell_loc).rev() {
diff --git a/src/machine/dispatch.rs b/src/machine/dispatch.rs
index 2428f7d2..af34bcd7 100644
--- a/src/machine/dispatch.rs
+++ b/src/machine/dispatch.rs
@@ -3277,7 +3277,7 @@ impl Machine {
                     &Instruction::PutPartialString(_, ref string, reg) => {
                         self.machine_st[reg] = backtrack_on_resource_error!(
                             self.machine_st,
-                            self.machine_st.heap.allocate_pstr(&string)
+                            self.machine_st.heap.allocate_pstr(string)
                         );
 
                         self.machine_st.p += 1;
diff --git a/src/machine/heap.rs b/src/machine/heap.rs
index fdf24047..e69050ab 100644
--- a/src/machine/heap.rs
+++ b/src/machine/heap.rs
@@ -612,7 +612,6 @@ impl Heap {
         }
     }
 
-    #[must_use]
     pub fn reserve(&mut self, num_cells: usize) -> Result<HeapWriter, usize> {
         let section;
         let len = heap_index!(num_cells);
@@ -745,10 +744,8 @@ impl Heap {
     // the heap to a pre-allocated resource error
     pub(crate) fn push_cell(&mut self, cell: HeapCellValue) -> Result<(), usize> {
         unsafe {
-            if self.inner.byte_len == self.inner.byte_cap {
-                if !self.grow() {
-                    return Err(self.resource_error_offset());
-                }
+            if self.inner.byte_len == self.inner.byte_cap && !self.grow() {
+                return Err(self.resource_error_offset());
             }
 
             // SAFETY:
@@ -1009,7 +1006,7 @@ impl<'a> PStrSegmentIter<'a> {
         let string_buf = unsafe {
             let char_ptr = heap.inner.ptr.add(pstr_loc);
             let slice = std::slice::from_raw_parts(char_ptr, heap.inner.byte_len - pstr_loc);
-            std::str::from_utf8_unchecked(&slice)
+            std::str::from_utf8_unchecked(slice)
         };
 
         PStrSegmentIter { string_buf }
diff --git a/src/machine/load_state.rs b/src/machine/load_state.rs
index 40e9a383..89c50153 100644
--- a/src/machine/load_state.rs
+++ b/src/machine/load_state.rs
@@ -546,27 +546,21 @@ impl<'a, LS: LoadState<'a>> Loader<'a, LS> {
             for export in removed_module.module_decl.exports.iter() {
                 match export {
                     ModuleExport::PredicateKey(ref key) => {
-                        match (
+                        if let (Some(module_code_idx), Some(target_code_idx)) = (
                             removed_module.code_dir.get(key).cloned(),
                             code_dir.get_mut(key).cloned(),
                         ) {
-                            (Some(module_code_idx), Some(target_code_idx)) => {
-                                let code_index_tbl =
-                                    &mut LS::machine_st(payload).arena.code_index_tbl;
-                                let module_code_ptr =
-                                    code_index_tbl.get_entry(module_code_idx.into());
-                                let target_code_ptr =
-                                    code_index_tbl.get_entry(target_code_idx.into());
+                            let code_index_tbl = &mut LS::machine_st(payload).arena.code_index_tbl;
+                            let module_code_ptr = code_index_tbl.get_entry(module_code_idx.into());
+                            let target_code_ptr = code_index_tbl.get_entry(target_code_idx.into());
 
-                                if module_code_ptr == target_code_ptr {
-                                    let old_index_ptr = target_code_idx
-                                        .replace(code_index_tbl, IndexPtr::undefined());
-                                    payload
-                                        .retraction_info
-                                        .push_record(predicate_retractor(*key, old_index_ptr));
-                                }
+                            if module_code_ptr == target_code_ptr {
+                                let old_index_ptr =
+                                    target_code_idx.replace(code_index_tbl, IndexPtr::undefined());
+                                payload
+                                    .retraction_info
+                                    .push_record(predicate_retractor(*key, old_index_ptr));
                             }
-                            _ => {}
                         }
                     }
                     ModuleExport::OpDecl(op_decl) => {
@@ -688,12 +682,12 @@ impl<'a, LS: LoadState<'a>> Loader<'a, LS> {
         let code_index_tbl = &mut LS::machine_st(&mut self.payload).arena.code_index_tbl;
 
         if module_name == atom!("user") {
-            return *self
+            *self
                 .wam_prelude
                 .indices
                 .code_dir
                 .entry(key)
-                .or_insert_with(|| CodeIndex::new(IndexPtr::undefined(), code_index_tbl));
+                .or_insert_with(|| CodeIndex::new(IndexPtr::undefined(), code_index_tbl))
         } else {
             self.get_or_insert_local_code_index(module_name, key)
         }
diff --git a/src/machine/loader.rs b/src/machine/loader.rs
index 685a69a0..08282f68 100644
--- a/src/machine/loader.rs
+++ b/src/machine/loader.rs
@@ -1407,10 +1407,10 @@ impl MachineState {
                     term_stack.push(Term::Literal(Cell::default(), Literal::try_from(addr).unwrap()));
                 }
                 (HeapCellValueTag::StackVar, h) => {
-                    term_stack.push(Term::Var(Cell::default(), VarPtr::from(format!("s_{}", h))));
+                    term_stack.push(Term::Var(Cell::default(), VarPtr::from(format!("s_{h}"))));
                 }
                 (HeapCellValueTag::Var | HeapCellValueTag::AttrVar, h) => {
-                    term_stack.push(Term::Var(Cell::default(), VarPtr::from(format!("_{}", h))));
+                    term_stack.push(Term::Var(Cell::default(), VarPtr::from(format!("_{h}"))));
                 }
                 (HeapCellValueTag::Atom, (name, arity)) => {
                     let h = iter.focus().value() as usize;
diff --git a/src/machine/machine_indices.rs b/src/machine/machine_indices.rs
index 4f04c2b1..7f7bfe35 100644
--- a/src/machine/machine_indices.rs
+++ b/src/machine/machine_indices.rs
@@ -159,17 +159,17 @@ impl From<CodeIndexOffset> for CodeIndex {
     }
 }
 
-impl Into<CodeIndexOffset> for CodeIndex {
+impl From<CodeIndex> for CodeIndexOffset {
     #[inline(always)]
-    fn into(self) -> CodeIndexOffset {
-        self.0
+    fn from(value: CodeIndex) -> CodeIndexOffset {
+        value.0
     }
 }
 
-impl Into<CodeIndexOffset> for &'_ CodeIndex {
+impl From<&'_ CodeIndex> for CodeIndexOffset {
     #[inline(always)]
-    fn into(self) -> CodeIndexOffset {
-        self.0
+    fn from(value: &'_ CodeIndex) -> CodeIndexOffset {
+        value.0
     }
 }
 
@@ -206,7 +206,7 @@ impl VarKey {
     #[inline]
     pub(crate) fn to_string(&self) -> String {
         match self {
-            VarKey::AnonVar(h) => format!("_{}", h),
+            VarKey::AnonVar(h) => format!("_{h}"),
             VarKey::VarPtr(var) => var.borrow().to_string(),
         }
     }
@@ -526,7 +526,7 @@ impl IndexStore {
         &'a self,
         range: R,
     ) -> impl Iterator<Item = Stream> + 'a {
-        self.streams.range(range).into_iter().copied()
+        self.streams.range(range).copied()
     }
 
     /// Forcibly sets `alias` to `stream`.
diff --git a/src/machine/machine_state.rs b/src/machine/machine_state.rs
index fac5d7b6..7663c952 100644
--- a/src/machine/machine_state.rs
+++ b/src/machine/machine_state.rs
@@ -659,8 +659,8 @@ impl MachineState {
                 &self.atom_tbl,
             )
         );
-
-        Ok(unify_fn!(*self, var_names_offset, var_names_addr))
+        unify_fn!(*self, var_names_offset, var_names_addr);
+        Ok(())
     }
 
     pub fn read_term_body(&mut self, mut term_write_result: TermWriteResult) -> CallResult {
diff --git a/src/machine/machine_state_impl.rs b/src/machine/machine_state_impl.rs
index f663656c..3f14253d 100644
--- a/src/machine/machine_state_impl.rs
+++ b/src/machine/machine_state_impl.rs
@@ -847,13 +847,11 @@ impl MachineState {
                             if let Some(c) = char_iter.next() {
                                 if n == 1 {
                                     self.unify_char(c, a3);
+                                } else if char_iter.next().is_some() {
+                                    unify_fn!(*self, pstr_loc_as_cell!(pstr_loc + c.len_utf8()), a3);
                                 } else {
-                                    if char_iter.next().is_some() {
-                                        unify_fn!(*self, pstr_loc_as_cell!(pstr_loc + c.len_utf8()), a3);
-                                    } else {
-                                        let tail_idx = Heap::pstr_tail_idx(pstr_loc + c.len_utf8());
-                                        unify_fn!(*self, self.heap[tail_idx], a3);
-                                    }
+                                    let tail_idx = Heap::pstr_tail_idx(pstr_loc + c.len_utf8());
+                                    unify_fn!(*self, self.heap[tail_idx], a3);
                                 }
                             } else {
                                 unreachable!()
diff --git a/src/machine/mock_wam.rs b/src/machine/mock_wam.rs
index b7201b71..0fcebd41 100644
--- a/src/machine/mock_wam.rs
+++ b/src/machine/mock_wam.rs
@@ -56,7 +56,7 @@ impl MockWAM {
         let mut printer = HCPrinter::new(
             &mut self.machine_st.heap,
             &mut self.machine_st.stack,
-            &mut self.machine_st.arena,
+            &self.machine_st.arena,
             &self.op_dir,
             PrinterOutputter::new(),
             term_write_result.heap_loc,
@@ -195,15 +195,11 @@ pub fn all_cells_marked_and_unforwarded(heap: &Heap, offset: usize) {
 
         assert!(
             cell.get_mark_bit(),
-            "cell {:?} at index {} is not marked",
-            cell,
-            curr_idx
+            "cell {cell:?} at index {curr_idx} is not marked"
         );
         assert!(
             !cell.get_forwarding_bit(),
-            "cell {:?} at index {} is forwarded",
-            cell,
-            curr_idx
+            "cell {cell:?} at index {curr_idx} is forwarded"
         );
     }
 }
@@ -227,9 +223,7 @@ pub fn all_cells_unmarked(iter: &impl SizedHeap) {
 
         assert!(
             !cell.get_mark_bit(),
-            "cell {:?} at index {} is still marked",
-            cell,
-            curr_idx
+            "cell {cell:?} at index {curr_idx} is still marked"
         );
     }
 }
@@ -255,6 +249,7 @@ pub(crate) fn parse_and_write_parsed_term_to_heap(
 
 impl Machine {
     /// For use in tests.
+    #[allow(clippy::unbuffered_bytes)]
     pub fn test_load_file(&mut self, file: &str) -> Vec<u8> {
         let stream = Stream::from_owned_string(
             std::fs::read_to_string(AsRef::<std::path::Path>::as_ref(file)).unwrap(),
@@ -266,6 +261,7 @@ impl Machine {
     }
 
     /// For use in tests.
+    #[allow(clippy::unbuffered_bytes)]
     pub fn test_load_string(&mut self, code: &str) -> Vec<u8> {
         let stream = Stream::from_owned_string(code.to_owned(), &mut self.machine_st.arena);
 
diff --git a/src/machine/streams.rs b/src/machine/streams.rs
index 1f9fae09..25e9a75a 100644
--- a/src/machine/streams.rs
+++ b/src/machine/streams.rs
@@ -1653,7 +1653,8 @@ impl MachineState {
                 };
 
                 stream.set_past_end_of_stream(true);
-                Ok(unify!(self, result, end_of_stream))
+                unify!(self, result, end_of_stream);
+                Ok(())
             }
             EOFAction::Reset => {
                 if !stream.reset() {
diff --git a/src/machine/system_calls.rs b/src/machine/system_calls.rs
index 6c861ae6..8c0eee0a 100644
--- a/src/machine/system_calls.rs
+++ b/src/machine/system_calls.rs
@@ -194,7 +194,7 @@ fn pstr_segment_char_count_up_to(
     let mut byte_offset = 0;
 
     if max_chars > 0 {
-        while let Some(c) = char_iter.next() {
+        for c in &mut char_iter {
             if c == '\u{0}' {
                 break;
             }
@@ -784,7 +784,7 @@ impl MachineState {
                 let steps = if max_steps > -1 {
                     std::cmp::min(max_steps, num_steps as i64)
                 } else {
-                    max_steps as i64
+                    max_steps
                 };
 
                 self.finalize_skip_max_list(steps, pstr_loc); // cell);
@@ -989,6 +989,7 @@ impl MachineState {
             }
         }
 
+        #[allow(clippy::never_loop)] // TODO why is there a loop here that never loops?
         loop {
             match lexer.lookahead_char() {
                 Err(e) if e.is_unexpected_eof() => {
@@ -2327,7 +2328,7 @@ impl Machine {
 
                 let cell = step_or_resource_error!(
                     self.machine_st,
-                    self.machine_st.heap.allocate_cstr(&*name.as_str())
+                    self.machine_st.heap.allocate_cstr(&name.as_str())
                 );
 
                 unify!(self.machine_st, self.machine_st.registers[2], cell);
@@ -2386,7 +2387,7 @@ impl Machine {
                     self.machine_st,
                     sized_iter_to_heap_list(
                         &mut self.machine_st.heap,
-                        (&*name).chars().count(),
+                        name.chars().count(),
                         iter,
                     )
                 );
@@ -2916,7 +2917,7 @@ impl Machine {
 
         let string = match Number::try_from((n, &self.machine_st.arena.f64_tbl)) {
             Ok(Number::Float(OrderedFloat(n))) => {
-                format!("{0:<20?}", n)
+                format!("{n:<20?}")
             }
             Ok(Number::Fixnum(n)) => n.get_num().to_string(),
             Ok(Number::Integer(n)) => n.to_string(),
@@ -3245,7 +3246,7 @@ impl Machine {
                     let n: u32 = (&*n).try_into().unwrap();
                     let n = char::try_from(n);
                     if let Ok(c) = n {
-                        write!(&mut stream, "{}", c).unwrap();
+                        write!(&mut stream, "{c}").unwrap();
                         return Ok(());
                     }
                 }
@@ -3253,7 +3254,7 @@ impl Machine {
                     let n = n.get_num();
 
                     if let Some(c) = u32::try_from(n).ok().and_then(char::from_u32) {
-                        write!(&mut stream, "{}", c).unwrap();
+                        write!(&mut stream, "{c}").unwrap();
                         return Ok(());
                     }
                 }
@@ -3295,13 +3296,13 @@ impl Machine {
             read_heap_cell!(addr,
                 (HeapCellValueTag::Atom, (name, _arity)) => {
                     if let Some(c) = name.as_char() {
-                        write!(&mut stream, "{}", c).unwrap();
+                        write!(&mut stream, "{c}").unwrap();
                         return Ok(());
                     }
                 }
                 /*
                 (HeapCellValueTag::Char, c) => {
-                    write!(&mut stream, "{}", c).unwrap();
+                    write!(&mut stream, "{c}").unwrap();
                     return Ok(());
                 }
                 */
@@ -3792,11 +3793,7 @@ impl Machine {
 
     #[inline(always)]
     pub(crate) fn first_stream(&mut self) {
-        let first_stream = self
-            .indices
-            .iter_streams(..)
-            .filter(|s| !s.is_null_stream())
-            .next();
+        let first_stream = self.indices.iter_streams(..).find(|s| !s.is_null_stream());
 
         if let Some(first_stream) = first_stream {
             let stream = first_stream.into();
@@ -3816,8 +3813,7 @@ impl Machine {
             .indices
             .iter_streams(prev_stream..)
             .filter(|s| !s.is_null_stream())
-            .skip(1)
-            .next();
+            .nth(1);
 
         if let Some(next_stream) = next_stream {
             let var = self.deref_register(2).as_var().unwrap();
@@ -3935,14 +3931,14 @@ impl Machine {
 
         self.indices.remove_stream(stream);
 
-        stream.close().or_else(|_| {
+        stream.close().map_err(|_| {
             let stub = functor_stub(atom!("close"), 1);
             let addr = stream.into();
             let err = self
                 .machine_st
                 .existence_error(ExistenceError::Stream(addr));
 
-            Err(self.machine_st.error_form(err, stub))
+            self.machine_st.error_form(err, stub)
         })
     }
 
@@ -4152,9 +4148,7 @@ impl Machine {
 
                 let mut functor_writer = Heap::functor_writer(functor);
 
-                if let Err(e) = functor_writer(heap) {
-                    return Err(e);
-                }
+                functor_writer(heap)?;
 
                 num_functors += 1;
             }
@@ -7637,7 +7631,7 @@ impl Machine {
 
         let buffer = git_version!(cargo_prefix = "cargo:", fallback = "unknown");
         let cstr_cell =
-            step_or_resource_error!(self.machine_st, self.machine_st.heap.allocate_cstr(&buffer));
+            step_or_resource_error!(self.machine_st, self.machine_st.heap.allocate_cstr(buffer));
 
         unify!(self.machine_st, cstr_cell, self.machine_st.registers[1]);
     }
@@ -8622,7 +8616,7 @@ impl Machine {
         ];
 
         for spec in SPECIFIERS {
-            fstr.push_str(&format!("'{}'=\"%{}\", ", spec, spec).to_string());
+            fstr.push_str(&format!("'{spec}'=\"%{spec}\", "));
         }
 
         fstr.push_str("finis].");
@@ -8719,7 +8713,7 @@ impl Machine {
                 Ok(result)
             }
             scraper::Node::Comment(comment) => {
-                let comment = self.machine_st.heap.allocate_cstr(&comment)?;
+                let comment = self.machine_st.heap.allocate_cstr(comment)?;
 
                 let result = str_loc_as_cell!(self.machine_st.heap.cell_len());
                 let mut writer = self.machine_st.heap.reserve(2)?;
diff --git a/src/machine/unify.rs b/src/machine/unify.rs
index 6ada6fb1..fdc430ee 100644
--- a/src/machine/unify.rs
+++ b/src/machine/unify.rs
@@ -290,7 +290,7 @@ pub(crate) trait Unifier: DerefMut<Target = MachineState> {
                 let machine_st = self.deref_mut();
 
                 let f1 = machine_st.arena.f64_tbl.get_entry(f1);
-                let f2 = machine_st.arena.f64_tbl.get_entry(f2.into());
+                let f2 = machine_st.arena.f64_tbl.get_entry(f2);
 
                 self.fail = f1 != f2;
             }
diff --git a/src/parser/ast.rs b/src/parser/ast.rs
index aa9ea077..18389225 100644
--- a/src/parser/ast.rs
+++ b/src/parser/ast.rs
@@ -10,7 +10,6 @@ use std::cell::{Cell, Ref, RefCell, RefMut};
 use std::fmt;
 use std::hash::Hash;
 use std::hash::Hasher;
-use std::i64;
 use std::io::{Error as IOError, ErrorKind};
 use std::ops::Not;
 use std::ops::RangeInclusive;
@@ -268,8 +267,8 @@ impl RegType {
 impl fmt::Display for RegType {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            RegType::Perm(val) => write!(f, "Y{}", val),
-            RegType::Temp(val) => write!(f, "X{}", val),
+            RegType::Perm(val) => write!(f, "Y{val}"),
+            RegType::Temp(val) => write!(f, "X{val}"),
         }
     }
 }
@@ -291,10 +290,10 @@ impl VarReg {
 impl fmt::Display for VarReg {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            VarReg::Norm(RegType::Perm(reg)) => write!(f, "Y{}", reg),
-            VarReg::Norm(RegType::Temp(reg)) => write!(f, "X{}", reg),
-            VarReg::ArgAndNorm(RegType::Perm(reg), arg) => write!(f, "Y{} A{}", reg, arg),
-            VarReg::ArgAndNorm(RegType::Temp(reg), arg) => write!(f, "X{} A{}", reg, arg),
+            VarReg::Norm(RegType::Perm(reg)) => write!(f, "Y{reg}"),
+            VarReg::Norm(RegType::Temp(reg)) => write!(f, "X{reg}"),
+            VarReg::ArgAndNorm(RegType::Perm(reg), arg) => write!(f, "Y{reg} A{arg}"),
+            VarReg::ArgAndNorm(RegType::Temp(reg), arg) => write!(f, "X{reg} A{arg}"),
         }
     }
 }
@@ -830,7 +829,7 @@ impl Var {
     #[inline(always)]
     pub fn to_string(&self) -> String {
         match self {
-            Var::InSitu(n) | Var::Generated(n) => format!("_{}", n),
+            Var::InSitu(n) | Var::Generated(n) => format!("_{n}"),
             Var::Named(value) => value.as_ref().clone(),
         }
     }
@@ -858,9 +857,9 @@ impl Term {
     }
 
     pub fn name(&self) -> Option<Atom> {
-        match self {
-            &Term::Literal(_, Literal::Atom(atom)) => Some(atom),
-            &Term::Clause(_, atom, ..) => Some(atom),
+        match *self {
+            Term::Literal(_, Literal::Atom(atom)) => Some(atom),
+            Term::Clause(_, atom, ..) => Some(atom),
             _ => None,
         }
     }
diff --git a/src/parser/lexer.rs b/src/parser/lexer.rs
index 5fd5b7ba..0ca5ef69 100644
--- a/src/parser/lexer.rs
+++ b/src/parser/lexer.rs
@@ -63,6 +63,7 @@ enum Number {
 
 impl Number {
     #[inline]
+    #[allow(clippy::wrong_self_convention)]
     fn to_literal(self) -> Literal {
         match self {
             Number::BigInt(ibig) => Literal::Integer(ibig),
@@ -80,6 +81,7 @@ enum NumberToken {
 
 impl NumberToken {
     #[inline]
+    #[allow(clippy::wrong_self_convention)]
     fn to_token(self) -> Option<Token> {
         match self {
             NumberToken::Number(number) => Some(Token::Literal(number.to_literal())),
@@ -959,8 +961,8 @@ impl<'a, R: CharRead> Lexer<'a, R> {
                     ))))
                 }
             },
-            Ok(NumberToken::Number(n)) => return Ok(Token::Literal(n.to_literal())),
-            Err(e) => return Err(e),
+            Ok(NumberToken::Number(n)) => Ok(Token::Literal(n.to_literal())),
+            Err(e) => Err(e),
         }
     }
 
diff --git a/src/parser/parser.rs b/src/parser/parser.rs
index 7a889520..a874face 100644
--- a/src/parser/parser.rs
+++ b/src/parser/parser.rs
@@ -111,7 +111,7 @@ pub(crate) fn as_partial_string(
                 tail_ref = tail;
             }
             Term::CompleteString(_, cstr) => {
-                string += &*cstr.as_str();
+                string += cstr.as_str();
                 tail = Term::Literal(Cell::default(), Literal::Atom(atom!("[]")));
                 break;
             }