Refactors out duplicate code

wemake_python_styleguide/logic/naming/name_nodes.py

@@ -1,7 +1,11 @@
 # -*- coding: utf-8 -*-
 
 import ast
-from typing import List, Optional
+import itertools
+from typing import Iterable, List, Optional
+
+from wemake_python_styleguide.compat.functions import get_assign_targets
+from wemake_python_styleguide.types import AnyAssign
 
 
 def is_same_variable(left: ast.AST, right: ast.AST) -> bool:
@@ -29,6 +33,15 @@ def get_assigned_name(node: ast.AST) -> Optional[str]:
     return None
 
 
+def flat_variable_names(nodes: Iterable[AnyAssign]) -> Iterable[str]:
+    """Returns flat variable names from several nodes."""
+    return itertools.chain.from_iterable((
+        get_variables_from_node(target)
+        for node in nodes
+        for target in get_assign_targets(node)
+    ))
+
+
 def get_variables_from_node(node: ast.AST) -> List[str]:
     """Gets the assigned names from the list of nodes."""
     names: List[str] = []

wemake_python_styleguide/visitors/ast/blocks.py

@@ -1,14 +1,13 @@
 # -*- coding: utf-8 -*-
 
 import ast
-import itertools
 from collections import defaultdict
 from typing import ClassVar, DefaultDict, Set, Union, cast
 
 from typing_extensions import final
 
-from wemake_python_styleguide.compat.functions import get_assign_targets
 from wemake_python_styleguide.logic.naming.name_nodes import (
+    flat_variable_names,
     get_variables_from_node,
 )
 from wemake_python_styleguide.logic.nodes import get_context, get_parent
@@ -127,10 +126,7 @@ def visit_locals(self, node: Union[AnyAssign, ast.arg]) -> None:
         if isinstance(node, ast.arg):
             names = {node.arg}
         else:
-            names = set(itertools.chain.from_iterable((
-                _extract_names(target)
-                for target in get_assign_targets(node)
-            )))
+            names = set(flat_variable_names([node]))
 
         self._scope(node, names, is_local=True)
         self.generic_visit(node)

wemake_python_styleguide/visitors/ast/classes.py

@@ -2,7 +2,7 @@
 
 import ast
 from collections import Counter
-from typing import ClassVar, Container, FrozenSet, List, Optional, Tuple
+from typing import ClassVar, FrozenSet, List, Optional, Tuple
 
 import astor
 from typing_extensions import final
@@ -17,7 +17,7 @@
     strings,
     walk,
 )
-from wemake_python_styleguide.logic.naming import access
+from wemake_python_styleguide.logic.naming import access, name_nodes
 from wemake_python_styleguide.violations import best_practices as bp
 from wemake_python_styleguide.violations import consistency, oop
 from wemake_python_styleguide.visitors import base, decorators
@@ -254,20 +254,6 @@ def visit_ClassDef(self, node: ast.ClassDef) -> None:
         self._check_attributes_shadowing(node)
         self.generic_visit(node)
 
-    # TODO: can be moved to logic, if is used anywhere else
-    def _flat_assign_names(
-        self,
-        nodes: List[types.AnyAssign],
-    ) -> Container[str]:
-        flat_assigns = []
-        for attribute in nodes:
-            targets = get_assign_targets(attribute)
-            flat_assigns.extend([
-                at.id for at in targets
-                if isinstance(at, ast.Name)
-            ])
-        return set(flat_assigns)
-
     def _get_attributes(
         self,
         node: ast.ClassDef,
@@ -288,7 +274,9 @@ def _get_attributes(
 
     def _check_attributes_shadowing(self, node: ast.ClassDef) -> None:
         class_attributes, instance_attributes = self._get_attributes(node)
-        class_attribute_names = self._flat_assign_names(class_attributes)
+        class_attribute_names = set(
+            name_nodes.flat_variable_names(class_attributes),
+        )
 
         for instance_attr in instance_attributes:
             if instance_attr.attr in class_attribute_names: