Clarify on non-Module roots

astroid/brain/brain_argparse.py

@@ -21,7 +21,7 @@ def infer_namespace(node, context: InferenceContext | None = None):
         "Namespace",
         lineno=node.lineno,
         col_offset=node.col_offset,
-        parent=AstroidManager().adhoc_module,  # this class is not real
+        parent=AstroidManager().synthetic_root,  # this class is not real
         end_lineno=node.end_lineno,
         end_col_offset=node.end_col_offset,
     )

astroid/brain/brain_builtin_inference.py

@@ -165,7 +165,7 @@ def _extend_builtins(class_transforms):
 
 def on_bootstrap():
     """Called by astroid_bootstrapping()."""
-    AstroidManager().cache_module(build_module("__astroid_adhoc"))
+    AstroidManager().cache_module(build_module("__astroid_synthetic"))
 
     _extend_builtins(
         {
@@ -653,7 +653,7 @@ def infer_property(
         # node.frame. It's somewhere in the builtins module, but we are special
         # casing it for each "property()" call, so we are making up the
         # definition on the spot, ad-hoc.
-        parent=AstroidManager().adhoc_module,
+        parent=AstroidManager().synthetic_root,
     )
     prop_func.postinit(
         body=[],

astroid/brain/brain_namedtuple_enum.py

@@ -194,7 +194,7 @@ def infer_named_tuple(
     """Specific inference function for namedtuple Call node."""
     tuple_base: nodes.Name = _extract_single_node("tuple")
     class_node, name, attributes = infer_func_form(
-        node, tuple_base, parent=AstroidManager().adhoc_module, context=context
+        node, tuple_base, parent=AstroidManager().synthetic_root, context=context
     )
 
     call_site = arguments.CallSite.from_call(node, context=context)
@@ -360,7 +360,7 @@ def value(self):
     class_node = infer_func_form(
         node,
         enum_meta,
-        parent=AstroidManager().adhoc_module,
+        parent=AstroidManager().synthetic_root,
         context=context,
         enum=True,
     )[0]

astroid/manager.py

@@ -116,8 +116,8 @@ def builtins_module(self) -> nodes.Module:
         return self.astroid_cache["builtins"]
 
     @property
-    def adhoc_module(self) -> nodes.Module:
-        return self.astroid_cache["__astroid_adhoc"]
+    def synthetic_root(self) -> nodes.Module:
+        return self.astroid_cache["__astroid_synthetic"]
 
     @property
     def prefer_stubs(self) -> bool:

astroid/nodes/node_ng.py

@@ -21,7 +21,7 @@
     overload,
 )
 
-from astroid import util
+from astroid import nodes, util
 from astroid.context import InferenceContext
 from astroid.exceptions import (
     AstroidError,
@@ -43,7 +43,6 @@
 
 
 if TYPE_CHECKING:
-    from astroid import nodes
     from astroid.nodes import _base_nodes
 
 
@@ -332,11 +331,13 @@ def root(self) -> nodes.Module:
         :returns: The root node.
         """
         if not (parent := self.parent):
-            return self  # type: ignore[return-value] # Only 'Module' does not have a parent node.
+            assert isinstance(self, nodes.Module)
+            return self
 
         while parent.parent:
             parent = parent.parent
-        return parent  # type: ignore[return-value] # Only 'Module' does not have a parent node.
+        assert isinstance(parent, nodes.Module)
+        return parent
 
     def child_sequence(self, child):
         """Search for the sequence that contains this child.

astroid/nodes/scoped_nodes/scoped_nodes.py

@@ -44,7 +44,6 @@
     Arguments,
     Const,
     NodeNG,
-    Unknown,
     _base_nodes,
     const_factory,
     node_classes,
@@ -1603,7 +1602,7 @@ def infer_call_result(
                     col_offset=0,
                     end_lineno=0,
                     end_col_offset=0,
-                    parent=AstroidManager().adhoc_module,
+                    parent=AstroidManager().synthetic_root,
                 )
                 new_class.hide = True
                 new_class.postinit(
@@ -2037,7 +2036,7 @@ def _infer_type_call(self, caller, context):
             col_offset=0,
             end_lineno=0,
             end_col_offset=0,
-            parent=Unknown(),
+            parent=caller.parent,
         )
 
         # Get the bases of the class.
@@ -2071,7 +2070,6 @@ def _infer_type_call(self, caller, context):
                 if isinstance(attr, node_classes.Const) and isinstance(attr.value, str):
                     result.locals[attr.value] = [value]
 
-        result.parent = caller.parent
         return result
 
     def infer_call_result(

astroid/objects.py

@@ -279,7 +279,7 @@ def __init__(self, call, name=None, lineno=None, col_offset=None, parent=None):
             name,
             lineno=lineno,
             col_offset=col_offset,
-            parent=AstroidManager().adhoc_module,
+            parent=AstroidManager().synthetic_root,
             end_col_offset=0,
             end_lineno=0,
         )

astroid/raw_building.py

@@ -670,9 +670,8 @@ def _astroid_bootstrapping() -> None:
             col_offset=0,
             end_lineno=0,
             end_col_offset=0,
-            parent=nodes.Unknown(),
+            parent=astroid_builtin,
         )
-        _UnionTypeType.parent = astroid_builtin
         union_type_doc_node = (
             nodes.Const(value=types.UnionType.__doc__)
             if types.UnionType.__doc__
@@ -707,9 +706,8 @@ def _astroid_bootstrapping() -> None:
                 col_offset=0,
                 end_lineno=0,
                 end_col_offset=0,
-                parent=nodes.Unknown(),
+                parent=astroid_builtin,
             )
-            klass.parent = astroid_builtin
             doc = _type.__doc__ if isinstance(_type.__doc__, str) else None
             klass.postinit(
                 bases=[],

tests/test_nodes.py

@@ -37,6 +37,7 @@
     ParentMissingError,
     StatementMissing,
 )
+from astroid.manager import AstroidManager
 from astroid.nodes.node_classes import (
     AssignAttr,
     AssignName,
@@ -1960,7 +1961,9 @@ def test_str_repr_no_warnings(node):
         if name == "self":
             continue
 
-        if "int" in param_type.annotation:
+        if name == "parent" and "NodeNG" in param_type.annotation:
+            args[name] = AstroidManager().synthetic_root
+        elif "int" in param_type.annotation:
             args[name] = random.randint(0, 50)
         elif (
             "NodeNG" in param_type.annotation