Remove unnecessary base class and dead code in `pylint.pyreverse.utils` (#6712)

* Remove unnecessary base class and dead code

* Add ChangeLog and whatsnew entry

1 files changed, 6 insertions, 43 deletions

diff --git a/pylint/pyreverse/utils.py b/pylint/pyreverse/utils.py
index c4c1c619a..7052791ec 100644
--- a/pylint/pyreverse/utils.py
+++ b/pylint/pyreverse/utils.py
@@ -17,9 +17,7 @@ import astroid
 from astroid import nodes
 
 if TYPE_CHECKING:
-    from pylint.pyreverse.diadefslib import DiaDefGenerator
     from pylint.pyreverse.diagrams import ClassDiagram, PackageDiagram
-    from pylint.pyreverse.inspector import Linker
 
     _CallbackT = Callable[
         [nodes.NodeNG],
@@ -121,8 +119,8 @@ class FilterMixIn:
         return not self.__mode & VIS_MOD[visibility]
 
 
-class ASTWalker:
-    """A walker visiting a tree in preorder, calling on the handler:.
+class LocalsVisitor:
+    """Visit a project by traversing the locals dictionary.
 
     * visit_<class name> on entering a node, where class name is the class of
     the node in lower case
@@ -131,36 +129,21 @@ class ASTWalker:
     the node in lower case
     """
 
-    def __init__(self, handler: DiaDefGenerator | Linker | LocalsVisitor) -> None:
-        self.handler = handler
+    def __init__(self) -> None:
         self._cache: dict[type[nodes.NodeNG], _CallbackTupleT] = {}
-
-    def walk(self, node: nodes.NodeNG, _done: set[nodes.NodeNG] | None = None) -> None:
-        """Walk on the tree from <node>, getting callbacks from handler."""
-        if _done is None:
-            _done = set()
-        if node in _done:
-            raise AssertionError((id(node), node, node.parent))
-        _done.add(node)
-        self.visit(node)
-        for child_node in node.get_children():
-            assert child_node is not node
-            self.walk(child_node, _done)
-        self.leave(node)
-        assert node.parent is not node
+        self._visited: set[nodes.NodeNG] = set()
 
     def get_callbacks(self, node: nodes.NodeNG) -> _CallbackTupleT:
         """Get callbacks from handler for the visited node."""
         klass = node.__class__
         methods = self._cache.get(klass)
         if methods is None:
-            handler = self.handler
             kid = klass.__name__.lower()
             e_method = getattr(
-                handler, f"visit_{kid}", getattr(handler, "visit_default", None)
+                self, f"visit_{kid}", getattr(self, "visit_default", None)
             )
             l_method = getattr(
-                handler, f"leave_{kid}", getattr(handler, "leave_default", None)
+                self, f"leave_{kid}", getattr(self, "leave_default", None)
             )
             self._cache[klass] = (e_method, l_method)
         else:
@@ -168,26 +151,6 @@ class ASTWalker:
         return e_method, l_method
 
     def visit(self, node: nodes.NodeNG) -> Any:
-        """Walk on the tree from <node>, getting callbacks from handler."""
-        method = self.get_callbacks(node)[0]
-        if method is not None:
-            method(node)
-
-    def leave(self, node: nodes.NodeNG) -> None:
-        """Walk on the tree from <node>, getting callbacks from handler."""
-        method = self.get_callbacks(node)[1]
-        if method is not None:
-            method(node)
-
-
-class LocalsVisitor(ASTWalker):
-    """Visit a project by traversing the locals dictionary."""
-
-    def __init__(self) -> None:
-        super().__init__(self)
-        self._visited: set[nodes.NodeNG] = set()
-
-    def visit(self, node: nodes.NodeNG) -> Any:
         """Launch the visit starting from the given node."""
         if node in self._visited:
             return None