refactor: CFG takes a FunctionType

src/builder/build_traits.rs

@@ -332,9 +332,8 @@ pub trait Dataflow: Container {
         let (cfg_node, _) = add_node_with_wires(
             self,
             NodeType::open_extensions(ops::CFG {
-                inputs: inputs.clone(),
-                outputs: output_types.clone(),
-                extension_delta,
+                signature: FunctionType::new(inputs.clone(), output_types.clone())
+                    .with_extension_delta(&extension_delta),
             }),
             input_wires,
         )?;

src/builder/cfg.rs

@@ -59,9 +59,7 @@ impl CFGBuilder<Hugr> {
     /// New CFG rooted HUGR builder
     pub fn new(signature: FunctionType) -> Result<Self, BuildError> {
         let cfg_op = ops::CFG {
-            inputs: signature.input.clone(),
-            outputs: signature.output.clone(),
-            extension_delta: signature.extension_reqs,
+            signature: signature.clone(),
         };
 
         let base = Hugr::new(NodeType::open_extensions(cfg_op));

src/hugr/validate.rs

@@ -966,9 +966,7 @@ mod test {
         b.replace_op(
             copy,
             NodeType::pure(ops::CFG {
-                inputs: type_row![BOOL_T],
-                outputs: type_row![BOOL_T],
-                extension_delta: ExtensionSet::new(),
+                signature: FunctionType::new(type_row![BOOL_T], type_row![BOOL_T]),
             }),
         );
         assert_matches!(

src/ops/controlflow.rs

@@ -96,9 +96,7 @@ impl Conditional {
 #[derive(Clone, Debug, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[allow(missing_docs)]
 pub struct CFG {
-    pub inputs: TypeRow,
-    pub outputs: TypeRow,
-    pub extension_delta: ExtensionSet,
+    pub signature: FunctionType,
 }
 
 impl_op_name!(CFG);
@@ -111,8 +109,7 @@ impl DataflowOpTrait for CFG {
     }
 
     fn signature(&self) -> FunctionType {
-        FunctionType::new(self.inputs.clone(), self.outputs.clone())
-            .with_extension_delta(&self.extension_delta)
+        self.signature.clone()
     }
 }