Fix pattern matching and block overlaps (#2893)

CHANGELOG.md

@@ -58,6 +58,8 @@ Semantic versioning in our case means:
 - Fixes `TryExceptMultipleReturnPathViolation` to work with `TryStar`
 - Fixes `IncorrectExceptOrderViolation` to work with `TryStar`
 - Fixes that `MatchStar` was not checked in pattern matching name assignments
+- Fixes pattern matching support
+  in `BlockAndLocalOverlapViolation` and `OuterScopeShadowingViolation`
 
 ### Misc
 

tests/test_visitors/test_ast/test_blocks/test_outer_scope_shadow.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY310
 from wemake_python_styleguide.violations.best_practices import (
     OuterScopeShadowingViolation,
 )
@@ -254,6 +255,22 @@ def function():
         ...
 """
 
+match_as_overlap = """
+import some
+
+def function():
+    match ...:
+        case 1 as some: ...
+"""
+
+match_star_overlap = """
+import some
+
+def function():
+    match ...:
+        case [*some]: ...
+"""
+
 
 @pytest.mark.parametrize('code', [
     correct_for_loop1,
@@ -300,6 +317,20 @@ def test_variable_used_correctly(
     constant_overlap5,
     constant_overlap6,
     walrus_overlap,
+    pytest.param(
+        match_as_overlap,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in Python 3.10',
+        ),
+    ),
+    pytest.param(
+        match_star_overlap,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in Python 3.10',
+        ),
+    ),
 ])
 def test_outer_variable_shadow(
     assert_errors,

tests/test_visitors/test_ast/test_blocks/test_overlap/test_blocks_overlap.py

@@ -1,5 +1,6 @@
 import pytest
 
+from wemake_python_styleguide.compat.constants import PY310
 from wemake_python_styleguide.violations.best_practices import (
     BlockAndLocalOverlapViolation,
 )
@@ -74,6 +75,27 @@ def context():
     ...
 """
 
+import_and_match_as = """
+import overlap
+
+match ...:
+    case 1 as overlap: ...
+"""
+
+import_and_match_as_implicit = """
+import overlap
+
+match ...:
+    case overlap: ...
+"""
+
+import_and_match_star = """
+import overlap
+
+match ...:
+    case [1, *overlap]: ...
+"""
+
 # Correct:
 
 unused_variables_overlap1 = """
@@ -121,6 +143,27 @@ def context():
     loop_and_loop1,
     loop_and_loop2,
     import_and_walrus,
+    pytest.param(
+        import_and_match_as,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in Python 3.10',
+        ),
+    ),
+    pytest.param(
+        import_and_match_as_implicit,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in Python 3.10',
+        ),
+    ),
+    pytest.param(
+        import_and_match_star,
+        marks=pytest.mark.skipif(
+            not PY310,
+            reason='Pattern matching was added in Python 3.10',
+        ),
+    ),
 ])
 def test_block_overlap(
     assert_errors,

wemake_python_styleguide/violations/best_practices.py

@@ -1738,7 +1738,7 @@ class OuterScopeShadowingViolation(ASTViolation):
 
 
     Solution:
-        Use different names and do not allow scoping.
+        Use different names.
 
     Example::
 

wemake_python_styleguide/visitors/ast/blocks.py

@@ -5,6 +5,7 @@
 from typing_extensions import TypeAlias, final
 
 from wemake_python_styleguide.compat.aliases import ForNodes, WithNodes
+from wemake_python_styleguide.compat.types import NamedMatch
 from wemake_python_styleguide.logic.naming.name_nodes import flat_variable_names
 from wemake_python_styleguide.logic.nodes import get_context, get_parent
 from wemake_python_styleguide.logic.scopes import defs, predicates
@@ -33,13 +34,23 @@
 _ScopePredicate: TypeAlias = Callable[[ast.AST, Set[str]], bool]
 _NamePredicate: TypeAlias = Callable[[ast.AST], bool]
 
+#: Named nodes.
+_NamedNode: TypeAlias = Union[
+    AnyFunctionDef,
+    ast.ClassDef,
+    ast.ExceptHandler,
+    NamedMatch,
+]
+
 
 @final
 @decorators.alias('visit_named_nodes', (
     'visit_FunctionDef',
     'visit_AsyncFunctionDef',
     'visit_ClassDef',
     'visit_ExceptHandler',
+    'visit_MatchAs',
+    'visit_MatchStar',
 ))
 @decorators.alias('visit_any_for', (
     'visit_For',
@@ -83,10 +94,7 @@ class BlockVariableVisitor(base.BaseNodeVisitor):
 
     # Blocks:
 
-    def visit_named_nodes(
-        self,
-        node: Union[AnyFunctionDef, ast.ClassDef, ast.ExceptHandler],
-    ) -> None:
+    def visit_named_nodes(self, node: _NamedNode) -> None:
         """Visits block nodes that have ``.name`` property."""
         names = {node.name} if node.name else set()
         self._scope(node, names, is_local=False)