feat: getter for PolyFuncType::body (#727)

required to update tket2 to latest hugr commits

src/builder/build_traits.rs

@@ -92,7 +92,7 @@ pub trait Container {
         name: impl Into<String>,
         signature: PolyFuncType,
     ) -> Result<FunctionBuilder<&mut Hugr>, BuildError> {
-        let body = signature.body.clone();
+        let body = signature.body().clone();
         let f_node = self.add_child_node(NodeType::new(
             ops::FuncDefn {
                 name: name.into(),

src/builder/dataflow.rs

@@ -147,7 +147,7 @@ impl FunctionBuilder<Hugr> {
     ///
     /// Error in adding DFG child nodes.
     pub fn new(name: impl Into<String>, signature: PolyFuncType) -> Result<Self, BuildError> {
-        let body = signature.body.clone();
+        let body = signature.body().clone();
         let op = ops::FuncDefn {
             signature,
             name: name.into(),

src/builder/module.rs

@@ -84,7 +84,7 @@ impl<T: AsMut<Hugr> + AsRef<Hugr>> ModuleBuilder<T> {
                 op_desc: "crate::ops::OpType::FuncDecl",
             })?
             .clone();
-        let body = signature.body.clone();
+        let body = signature.body().clone();
         self.hugr_mut().replace_op(
             f_node,
             NodeType::new_pure(ops::FuncDefn { name, signature }),

src/ops/validate.rs

@@ -79,7 +79,7 @@ impl ValidateOp for super::FuncDefn {
     ) -> Result<(), ChildrenValidationError> {
         // We check type-variables are declared in `validate_subtree`, so here
         // we can just assume all type variables are valid regardless of binders.
-        let FunctionType { input, output, .. } = &self.signature.body;
+        let FunctionType { input, output, .. } = self.signature.body();
         validate_io_nodes(input, output, "function definition", children)
     }
 }

src/types/poly_func.rs

@@ -31,7 +31,7 @@ pub struct PolyFuncType {
     /// [TypeArg]: super::type_param::TypeArg
     params: Vec<TypeParam>,
     /// Template for the function. May contain variables up to length of [Self::params]
-    pub(crate) body: FunctionType,
+    body: FunctionType,
 }
 
 impl From<FunctionType> for PolyFuncType {
@@ -49,6 +49,11 @@ impl PolyFuncType {
         &self.params
     }
 
+    /// The body of the type, a function type.
+    pub fn body(&self) -> &FunctionType {
+        &self.body
+    }
+
     /// Create a new PolyFuncType given the kinds of the variables it declares
     /// and the underlying [FunctionType].
     pub fn new(params: impl Into<Vec<TypeParam>>, body: FunctionType) -> Self {