Add tests about matching __slots__ against structural type (PY-29233)

python/src/com/jetbrains/python/psi/types/PyClassTypeImpl.java

@@ -12,7 +12,6 @@ import com.intellij.psi.PsiInvalidElementAccessException;
 import com.intellij.psi.util.PsiTreeUtil;
 import com.intellij.psi.util.QualifiedName;
 import com.intellij.util.ArrayUtil;
-import com.intellij.util.ObjectUtils;
 import com.intellij.util.ProcessingContext;
 import com.intellij.util.Processor;
 import com.intellij.util.containers.ContainerUtil;
@@ -681,7 +680,9 @@ public class PyClassTypeImpl extends UserDataHolderBase implements PyClassType {
       result.add(expression.getName());
     }
 
-    result.addAll(ObjectUtils.notNull(myClass.getSlots(context), Collections.emptyList()));
+    if (myClass.isNewStyleClass(context)) {
+      result.addAll(ContainerUtil.notNullize(myClass.getOwnSlots()));
+    }
 
     for (PyClassMembersProvider provider : Extensions.getExtensions(PyClassMembersProvider.EP_NAME)) {
       for (PyCustomMember member : provider.getMembers(this, null, context)) {

python/testData/inspections/PyTypeCheckerInspection/PassClassWithDunderSlotsToMethodThatUsesSlottedAttribute.py

@@ -2,8 +2,29 @@ class A(object):
     __slots__ = 'x', 'y'
 
 
+class B(object):
+    __slots__ = ['x']
+
+class C(B):
+    pass
+
+
+class D(object):
+    pass
+
+class E(D):
+    __slots__ = ['x']
+
+
+class F:
+    __slots__ = ['x']
+
+
 def copy_values(a):
     print(a.x)
 
 
-copy_values(A())
+copy_values(A())
+copy_values(C())
+copy_values(E())
+copy_values(<warning descr="Type 'D' doesn't have expected attribute 'x'">D()</warning>)

python/testSrc/com/jetbrains/python/inspections/PyTypeCheckerInspectionTest.java

@@ -344,7 +344,7 @@ public class PyTypeCheckerInspectionTest extends PyInspectionTestCase {
     doTest();
   }
 
-  // PY-22222
+  // PY-22222, PY-29233
   public void testPassClassWithDunderSlotsToMethodThatUsesSlottedAttribute() {
     doTest();
   }