diff --git a/crates/circuit/src/circuit_data.rs b/crates/circuit/src/circuit_data.rs
index ec17b4f8a9e..02e2021518b 100644
--- a/crates/circuit/src/circuit_data.rs
+++ b/crates/circuit/src/circuit_data.rs
@@ -898,12 +898,13 @@ impl CircuitData {
                 )));
             }
             let mut old_table = std::mem::take(&mut self.param_table);
+            let owned_iter: Vec<Param> = array.iter().map(|value| Param::Float(*value)).collect();
             self.assign_parameters_inner(
                 sequence.py(),
-                array
+                owned_iter
                     .iter()
                     .zip(old_table.drain_ordered())
-                    .map(|(value, (param_ob, uses))| (param_ob, Param::Float(*value), uses)),
+                    .map(|(value, (obj, uses))| (obj, value, uses)),
             )
         } else {
             let values = sequence
@@ -918,12 +919,21 @@ impl CircuitData {
     fn assign_parameters_mapping(&mut self, mapping: Bound<PyAny>) -> PyResult<()> {
         let py = mapping.py();
         let mut items = Vec::new();
+        let mut objs = Vec::new();
         for item in mapping.call_method0("items")?.iter()? {
             let (param_ob, value) = item?.extract::<(Py<PyAny>, AssignParam)>()?;
-            let uuid = ParameterUuid::from_parameter(param_ob.bind(py))?;
-            items.push((param_ob, value.0, self.param_table.pop(uuid)?));
+            items.push(value);
+            objs.push(param_ob); // We need to separate the objects to avoid cloning.
         }
-        self.assign_parameters_inner(py, items)
+        let borrowed_iterator: PyResult<Vec<_>> = items
+            .iter()
+            .zip(objs.into_iter())
+            .map(|(value, param_obj)| -> PyResult<_> {
+                let uuid = ParameterUuid::from_parameter(param_obj.bind(py))?;
+                Ok((param_obj, &value.0, self.param_table.pop(uuid)?))
+            })
+            .collect();
+        self.assign_parameters_inner(py, borrowed_iterator?)
     }
 
     pub fn clear(&mut self) {
@@ -1086,7 +1096,6 @@ impl CircuitData {
             py,
             slice
                 .iter()
-                .cloned()
                 .zip(old_table.drain_ordered())
                 .map(|(value, (param_ob, uses))| (param_ob, value, uses)),
         )
@@ -1095,9 +1104,9 @@ impl CircuitData {
     /// Assigns parameters to circuit data based on a mapping of `ParameterUuid` : `Param`.
     /// This mapping assumes that the provided `ParameterUuid` keys are instances
     /// of `ParameterExpression`.
-    pub fn assign_parameters_from_mapping<I>(&mut self, py: Python, iter: I) -> PyResult<()>
+    pub fn assign_parameters_from_mapping<'a, I>(&mut self, py: Python, iter: I) -> PyResult<()>
     where
-        I: IntoIterator<Item = (ParameterUuid, Param)>,
+        I: IntoIterator<Item = (ParameterUuid, &'a Param)>,
     {
         let mut items = Vec::new();
         for (param_uuid, value) in iter {
@@ -1112,9 +1121,9 @@ impl CircuitData {
         self.assign_parameters_inner(py, items)
     }
 
-    fn assign_parameters_inner<I>(&mut self, py: Python, iter: I) -> PyResult<()>
+    fn assign_parameters_inner<'a, I>(&mut self, py: Python, iter: I) -> PyResult<()>
     where
-        I: IntoIterator<Item = (Py<PyAny>, Param, HashSet<ParameterUse>)>,
+        I: IntoIterator<Item = (Py<PyAny>, &'a Param, HashSet<ParameterUse>)>,
     {
         let inconsistent =
             || PyRuntimeError::new_err("internal error: circuit parameter table is inconsistent");
@@ -1162,7 +1171,7 @@ impl CircuitData {
                         };
                         self.set_global_phase(
                             py,
-                            bind_expr(expr.bind_borrowed(py), &param_ob, &value, true)?,
+                            bind_expr(expr.bind_borrowed(py), &param_ob, value, true)?,
                         )?;
                     }
                     ParameterUse::Index {
@@ -1177,7 +1186,7 @@ impl CircuitData {
                                 return Err(inconsistent());
                             };
                             params[parameter] =
-                                match bind_expr(expr.bind_borrowed(py), &param_ob, &value, true)? {
+                                match bind_expr(expr.bind_borrowed(py), &param_ob, value, true)? {
                                     Param::Obj(obj) => {
                                         return Err(CircuitError::new_err(format!(
                                             "bad type after binding for gate '{}': '{}'",
@@ -1215,12 +1224,8 @@ impl CircuitData {
                                 Param::ParameterExpression(expr) => {
                                     // For user gates, we don't coerce floats to integers in `Param`
                                     // so that users can use them if they choose.
-                                    let new_param = bind_expr(
-                                        expr.bind_borrowed(py),
-                                        &param_ob,
-                                        &value,
-                                        false,
-                                    )?;
+                                    let new_param =
+                                        bind_expr(expr.bind_borrowed(py), &param_ob, value, false)?;
                                     // Historically, `assign_parameters` called `validate_parameter`
                                     // only when a `ParameterExpression` became fully bound.  Some
                                     // "generalised" (or user) gates fail without this, though