diff --git a/nac3core/src/codegen/types/list.rs b/nac3core/src/codegen/types/list.rs
index 4561b483..7b082365 100644
--- a/nac3core/src/codegen/types/list.rs
+++ b/nac3core/src/codegen/types/list.rs
@@ -55,6 +55,19 @@ impl<'ctx> ListType<'ctx> {
         Ok(())
     }
 
+    /// Creates an LLVM type corresponding to the expected structure of a `List`.
+    #[must_use]
+    fn llvm_type(
+        ctx: &'ctx Context,
+        element_type: BasicTypeEnum<'ctx>,
+        llvm_usize: IntType<'ctx>,
+    ) -> PointerType<'ctx> {
+        // struct List { data: T*, size: size_t }
+        let field_tys = [element_type.ptr_type(AddressSpace::default()).into(), llvm_usize.into()];
+
+        ctx.struct_type(&field_tys, false).ptr_type(AddressSpace::default())
+    }
+
     /// Creates an instance of [`ListType`].
     #[must_use]
     pub fn new<G: CodeGenerator + ?Sized>(
@@ -63,12 +76,7 @@ impl<'ctx> ListType<'ctx> {
         element_type: BasicTypeEnum<'ctx>,
     ) -> Self {
         let llvm_usize = generator.get_size_type(ctx);
-        let llvm_list = ctx
-            .struct_type(
-                &[element_type.ptr_type(AddressSpace::default()).into(), llvm_usize.into()],
-                false,
-            )
-            .ptr_type(AddressSpace::default());
+        let llvm_list = Self::llvm_type(ctx, element_type, llvm_usize);
 
         ListType::from_type(llvm_list, llvm_usize)
     }
diff --git a/nac3core/src/codegen/types/ndarray.rs b/nac3core/src/codegen/types/ndarray.rs
index ca463b6a..98bcdb62 100644
--- a/nac3core/src/codegen/types/ndarray.rs
+++ b/nac3core/src/codegen/types/ndarray.rs
@@ -73,6 +73,27 @@ impl<'ctx> NDArrayType<'ctx> {
         Ok(())
     }
 
+    /// Creates an LLVM type corresponding to the expected structure of an `NDArray`.
+    #[must_use]
+    fn llvm_type(
+        ctx: &'ctx Context,
+        dtype: BasicTypeEnum<'ctx>,
+        llvm_usize: IntType<'ctx>,
+    ) -> PointerType<'ctx> {
+        // struct NDArray { num_dims: size_t, dims: size_t*, data: T* }
+        //
+        // * num_dims: Number of dimensions in the array
+        // * dims: Pointer to an array containing the size of each dimension
+        // * data: Pointer to an array containing the array data
+        let field_tys = [
+            llvm_usize.into(),
+            llvm_usize.ptr_type(AddressSpace::default()).into(),
+            dtype.ptr_type(AddressSpace::default()).into(),
+        ];
+
+        ctx.struct_type(&field_tys, false).ptr_type(AddressSpace::default())
+    }
+
     /// Creates an instance of [`ListType`].
     #[must_use]
     pub fn new<G: CodeGenerator + ?Sized>(
@@ -81,22 +102,7 @@ impl<'ctx> NDArrayType<'ctx> {
         dtype: BasicTypeEnum<'ctx>,
     ) -> Self {
         let llvm_usize = generator.get_size_type(ctx);
-
-        // struct NDArray { num_dims: size_t, dims: size_t*, data: T* }
-        //
-        // * num_dims: Number of dimensions in the array
-        // * dims: Pointer to an array containing the size of each dimension
-        // * data: Pointer to an array containing the array data
-        let llvm_ndarray = ctx
-            .struct_type(
-                &[
-                    llvm_usize.into(),
-                    llvm_usize.ptr_type(AddressSpace::default()).into(),
-                    dtype.ptr_type(AddressSpace::default()).into(),
-                ],
-                false,
-            )
-            .ptr_type(AddressSpace::default());
+        let llvm_ndarray = Self::llvm_type(ctx, dtype, llvm_usize);
 
         NDArrayType::from_type(llvm_ndarray, llvm_usize)
     }
diff --git a/nac3core/src/codegen/types/range.rs b/nac3core/src/codegen/types/range.rs
index 89a1b723..49c43882 100644
--- a/nac3core/src/codegen/types/range.rs
+++ b/nac3core/src/codegen/types/range.rs
@@ -47,11 +47,18 @@ impl<'ctx> RangeType<'ctx> {
         Ok(())
     }
 
+    /// Creates an LLVM type corresponding to the expected structure of a `Range`.
+    #[must_use]
+    fn llvm_type(ctx: &'ctx Context) -> PointerType<'ctx> {
+        // typedef int32_t Range[3];
+        let llvm_i32 = ctx.i32_type();
+        llvm_i32.array_type(3).ptr_type(AddressSpace::default())
+    }
+
     /// Creates an instance of [`RangeType`].
     #[must_use]
     pub fn new(ctx: &'ctx Context) -> Self {
-        let llvm_i32 = ctx.i32_type();
-        let llvm_range = llvm_i32.array_type(3).ptr_type(AddressSpace::default());
+        let llvm_range = Self::llvm_type(ctx);
 
         RangeType::from_type(llvm_range)
     }