Don't infer MatchAs in assigned_stmts if pattern is not None (#1096)

* Move protocol match tests to separate class
* Don't infer MatchAs in assigned_stmts if pattern is not None

2 files changed, 70 insertions, 61 deletions

diff --git a/astroid/protocols.py b/astroid/protocols.py
index 228000ab..f97fb948 100644
--- a/astroid/protocols.py
+++ b/astroid/protocols.py
@@ -839,8 +839,10 @@ def match_as_assigned_stmts(
     """Infer MatchAs as the Match subject if it's the only MatchCase pattern
     else raise StopIteration to yield Uninferable.
     """
-    if isinstance(self.parent, nodes.MatchCase) and isinstance(
-        self.parent.parent, nodes.Match
+    if (
+        isinstance(self.parent, nodes.MatchCase)
+        and isinstance(self.parent.parent, nodes.Match)
+        and self.pattern is None
     ):
         yield self.parent.parent.subject
 
diff --git a/tests/unittest_protocols.py b/tests/unittest_protocols.py
index e130b570..3059e55b 100644
--- a/tests/unittest_protocols.py
+++ b/tests/unittest_protocols.py
@@ -267,71 +267,78 @@ def test_named_expr_inference():
 
 
 @pytest.mark.skipif(not PY310_PLUS, reason="Match requires python 3.10")
-def test_assigned_stmts_match_mapping():
-    """Assigned_stmts for MatchMapping not yet implemented.
+class TestPatternMatching:
+    @staticmethod
+    def test_assigned_stmts_match_mapping():
+        """Assigned_stmts for MatchMapping not yet implemented.
 
-    Test the result is 'Uninferable' and no exception is raised.
-    """
-    assign_stmts = extract_node(
+        Test the result is 'Uninferable' and no exception is raised.
         """
-    var = {1: "Hello", 2: "World"}
-    match var:
-        case {**rest}:  #@
-            pass
-    """
-    )
-    match_mapping: nodes.MatchMapping = assign_stmts.pattern  # type: ignore
-    assert match_mapping.rest
-    assigned = next(match_mapping.rest.assigned_stmts())
-    assert assigned == util.Uninferable
-
-
-@pytest.mark.skipif(not PY310_PLUS, reason="Match requires python 3.10")
-def test_assigned_stmts_match_star():
-    """Assigned_stmts for MatchStar not yet implemented.
-
-    Test the result is 'Uninferable' and no exception is raised.
-    """
-    assign_stmts = extract_node(
+        assign_stmts = extract_node(
+            """
+        var = {1: "Hello", 2: "World"}
+        match var:
+            case {**rest}:  #@
+                pass
         """
-    var = (0, 1, 2)
-    match var:
-        case (0, 1, *rest):  #@
-            pass
-    """
-    )
-    match_sequence: nodes.MatchSequence = assign_stmts.pattern  # type: ignore
-    match_star = match_sequence.patterns[2]
-    assert isinstance(match_star, nodes.MatchStar) and match_star.name
-    assigned = next(match_star.name.assigned_stmts())
-    assert assigned == util.Uninferable
+        )
+        match_mapping: nodes.MatchMapping = assign_stmts.pattern  # type: ignore
+        assert match_mapping.rest
+        assigned = next(match_mapping.rest.assigned_stmts())
+        assert assigned == util.Uninferable
 
+    @staticmethod
+    def test_assigned_stmts_match_star():
+        """Assigned_stmts for MatchStar not yet implemented.
 
-@pytest.mark.skipif(not PY310_PLUS, reason="Match requires python 3.10")
-def test_assigned_stmts_match_as():
-    """Assigned_stmts for MatchAs only implemented for the most basic case (y)."""
-    assign_stmts = extract_node(
+        Test the result is 'Uninferable' and no exception is raised.
         """
-    var = 42
-    match var:  #@
-        case 2 | x:  #@
-            pass
-        case y:  #@
-            pass
-    """
-    )
-    subject: nodes.Const = assign_stmts[0].subject  # type: ignore
-    match_or: nodes.MatchOr = assign_stmts[1].pattern  # type: ignore
-    match_as: nodes.MatchAs = assign_stmts[2].pattern  # type: ignore
-
-    assert match_as.name
-    assigned_match_as = next(match_as.name.assigned_stmts())
-    assert assigned_match_as == subject
-
-    match_or_1 = match_or.patterns[1]
-    assert isinstance(match_or_1, nodes.MatchAs) and match_or_1.name
-    assigned_match_or_1 = next(match_or_1.name.assigned_stmts())
-    assert assigned_match_or_1 == util.Uninferable
+        assign_stmts = extract_node(
+            """
+        var = (0, 1, 2)
+        match var:
+            case (0, 1, *rest):  #@
+                pass
+        """
+        )
+        match_sequence: nodes.MatchSequence = assign_stmts.pattern  # type: ignore
+        match_star = match_sequence.patterns[2]
+        assert isinstance(match_star, nodes.MatchStar) and match_star.name
+        assigned = next(match_star.name.assigned_stmts())
+        assert assigned == util.Uninferable
+
+    @staticmethod
+    def test_assigned_stmts_match_as():
+        """Assigned_stmts for MatchAs only implemented for the most basic case (y)."""
+        assign_stmts = extract_node(
+            """
+        var = 42
+        match var:  #@
+            case 2 | x:  #@
+                pass
+            case (1, 2) as y:  #@
+                pass
+            case z:  #@
+                pass
+        """
+        )
+        subject: nodes.Const = assign_stmts[0].subject  # type: ignore
+        match_or: nodes.MatchOr = assign_stmts[1].pattern  # type: ignore
+        match_as_with_pattern: nodes.MatchAs = assign_stmts[2].pattern  # type: ignore
+        match_as: nodes.MatchAs = assign_stmts[3].pattern  # type: ignore
+
+        match_or_1 = match_or.patterns[1]
+        assert isinstance(match_or_1, nodes.MatchAs) and match_or_1.name
+        assigned_match_or_1 = next(match_or_1.name.assigned_stmts())
+        assert assigned_match_or_1 == util.Uninferable
+
+        assert match_as_with_pattern.name and match_as_with_pattern.pattern
+        assigned_match_as_pattern = next(match_as_with_pattern.name.assigned_stmts())
+        assert assigned_match_as_pattern == util.Uninferable
+
+        assert match_as.name
+        assigned_match_as = next(match_as.name.assigned_stmts())
+        assert assigned_match_as == subject
 
 
 if __name__ == "__main__":