Throw attribute error NIRNode constructor

Fix for #120

Throws `AttributeError` on call `NIRNode.__init__`.

nir/ir/node.py

@@ -1,9 +1,10 @@
+from abc import ABC
 from dataclasses import asdict, dataclass
 from typing import Any, Dict
 
 
 @dataclass(eq=False)
-class NIRNode:
+class NIRNode(ABC):
     """Base superclass of Neural Intermediate Representation Unit (NIR).
 
     All NIR primitives inherit from this class, but NIRNodes should never be
@@ -16,6 +17,9 @@ class NIRNode:
     # output_type: Dict[str, np.ndarray] = field(init=False, kw_only=True)
     # metadata: Dict[str, Any] = field(init=True, default_factory=dict)
 
+    def __init__(self) -> None:
+        raise AttributeError("NIRNode does not have a default constructor.")
+
     def __eq__(self, other):
         return self is other
 

tests/test_ir.py

@@ -582,3 +582,13 @@ def test_conv_type_inference():
             raise AssertionError(f"type check failed for: {name}")
         graph.infer_types()
         assert graph._check_types(), f"type inference failed for: {name}"
+
+
+def test_node():
+    try:
+        node = nir.ir.NIRNode()
+        assert (
+            node is None
+        ), f"test failed, we should not be able to construct an NIRNode: {node}"
+    except AttributeError:
+        pass