diff --git a/tket2/src/extension.rs b/tket2/src/extension.rs
index eabf63e1..5c7c032d 100644
--- a/tket2/src/extension.rs
+++ b/tket2/src/extension.rs
@@ -21,9 +21,6 @@ pub mod rotation;
 pub mod sympy;
 
 use sympy::SympyOpDef;
-/// Backwards compatible exports.
-/// TODO: Remove in a breaking release.
-pub use sympy::{SYM_EXPR_NAME, SYM_EXPR_T, SYM_OP_ID};
 
 /// The ID of the TKET1 extension.
 pub const TKET1_EXTENSION_ID: ExtensionId = IdentList::new_unchecked("TKET1");
diff --git a/tket2/src/ops.rs b/tket2/src/ops.rs
index 30c90185..2e8fb508 100644
--- a/tket2/src/ops.rs
+++ b/tket2/src/ops.rs
@@ -1,6 +1,6 @@
 use crate::extension::rotation::ROTATION_TYPE;
-use crate::extension::sympy::SympyOpDef;
-use crate::extension::{SYM_OP_ID, TKET2_EXTENSION_ID as EXTENSION_ID};
+use crate::extension::sympy::{SympyOpDef, SYM_OP_ID};
+use crate::extension::TKET2_EXTENSION_ID as EXTENSION_ID;
 use hugr::ops::custom::ExtensionOp;
 use hugr::ops::NamedOp;
 use hugr::{
diff --git a/tket2/src/passes/commutation.rs b/tket2/src/passes/commutation.rs
index cf4e1e8b..fc167023 100644
--- a/tket2/src/passes/commutation.rs
+++ b/tket2/src/passes/commutation.rs
@@ -281,14 +281,9 @@ impl Rewrite for PullForward {
     }
 
     fn invalidation_set(&self) -> impl Iterator<Item = Node> {
-        // TODO: This could avoid creating a vec, but it'll be easier to do once
-        // return position impl trait is available.
-        // This is done in the Rewrite trait of hugr so once that version
-        // is released, it can be updated here
-        let mut nodes = vec![self.command.node()];
+        let cmd_node = std::iter::once(self.command.node());
         let next_nodes = self.new_nexts.values().map(|c| c.node());
-        nodes.extend(next_nodes);
-        nodes.into_iter()
+        cmd_node.chain(next_nodes)
     }
 }
 
diff --git a/tket2/src/rewrite/strategy.rs b/tket2/src/rewrite/strategy.rs
index a55159ad..5658d9ff 100644
--- a/tket2/src/rewrite/strategy.rs
+++ b/tket2/src/rewrite/strategy.rs
@@ -349,20 +349,6 @@ impl LexicographicCostFunction<fn(&OpType) -> usize, 2> {
         Self::cx_count().into_greedy_strategy()
     }
 
-    /// Non-increasing rewrite strategy based on CX count.
-    ///
-    /// A fine-grained cost function given by the total number of quantum gates
-    /// is used to rank circuits with equal CX count.
-    ///
-    /// This is probably a good default for NISQ-y circuit optimisation.
-    ///
-    /// Deprecated: Use `default_cx_strategy` instead.
-    // TODO: Remove this method in the next breaking release.
-    #[deprecated(since = "0.5.1", note = "Use `default_cx_strategy` instead.")]
-    pub fn default_cx() -> ExhaustiveGreedyStrategy<Self> {
-        Self::default_cx_strategy()
-    }
-
     /// Non-increasing rewrite cost function based on CX gate count.
     ///
     /// A fine-grained cost function given by the total number of quantum gates