Box LoadStatePayload when storing it in the heap

src/machine/loader.rs

@@ -1098,7 +1098,7 @@ impl Machine {
 
     #[inline]
     pub(crate) fn push_load_state_payload(&mut self) {
-        let payload = LoadStatePayload::new(self);
+        let payload = Box::new(LoadStatePayload::new(self));
         let addr = Addr::LoadStatePayload(
             self.machine_st
                 .heap
@@ -1171,7 +1171,8 @@ impl Machine {
     ) {
         match result {
             Ok(payload) => {
-                self.machine_st.heap[evacuable_h] = HeapCellValue::LoadStatePayload(payload);
+                self.machine_st.heap[evacuable_h] =
+                    HeapCellValue::LoadStatePayload(Box::new(payload));
             }
             Err(e) => {
                 self.throw_session_error(e, (clause_name!("load"), 1));
@@ -1785,7 +1786,7 @@ impl<'a> Loader<'a, LiveTermStream> {
 
     pub(super) fn from_load_state_payload(
         wam: &'a mut Machine,
-        mut payload: LoadStatePayload,
+        mut payload: Box<LoadStatePayload>,
     ) -> Self {
         Loader {
             term_stream: mem::replace(

src/machine/machine_indices.rs

@@ -311,7 +311,7 @@ pub enum HeapCellValue {
     Atom(ClauseName, Option<SharedOpDesc>),
     DBRef(DBRef),
     Integer(Rc<Integer>),
-    LoadStatePayload(LoadStatePayload),
+    LoadStatePayload(Box<LoadStatePayload>),
     NamedStr(usize, ClauseName, Option<SharedOpDesc>), // arity, name, precedence/Specifier if it has one.
     Rational(Rc<Rational>),
     PartialString(PartialString, bool), // the partial string, a bool indicating whether it came from a Constant.
@@ -324,10 +324,10 @@ impl HeapCellValue {
     pub fn as_addr(&self, focus: usize) -> Addr {
         match self {
             HeapCellValue::Addr(ref a) => *a,
-            HeapCellValue::Atom(..)
-            | HeapCellValue::DBRef(..)
-            | HeapCellValue::Integer(..)
-            | HeapCellValue::Rational(..) => Addr::Con(focus),
+            HeapCellValue::Atom(..) |
+            HeapCellValue::DBRef(..) |
+            HeapCellValue::Integer(..) |
+            HeapCellValue::Rational(..) => Addr::Con(focus),
             HeapCellValue::LoadStatePayload(_) => Addr::LoadStatePayload(focus),
             HeapCellValue::NamedStr(_, _, _) => Addr::Str(focus),
             HeapCellValue::PartialString(..) => Addr::PStrLocation(focus, 0),