diff --git a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/PyNamedParameterImpl.java b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/PyNamedParameterImpl.java
index 68aef3c6cdbb..8613eab64a96 100644
--- a/python/python-psi-impl/src/com/jetbrains/python/psi/impl/PyNamedParameterImpl.java
+++ b/python/python-psi-impl/src/com/jetbrains/python/psi/impl/PyNamedParameterImpl.java
@@ -271,6 +271,7 @@ public class PyNamedParameterImpl extends PyBaseElementImpl<PyNamedParameterStub
 
     final Ref<Boolean> parameterWasReassigned = Ref.create(false);
     final Ref<Boolean> noneComparison = Ref.create(false);
+    final PyResolveContext resolveContext = PyResolveContext.defaultContext(context);
 
     if (owner != null && name != null) {
       owner.accept(new PyRecursiveElementVisitor() {
@@ -378,8 +379,10 @@ public class PyNamedParameterImpl extends PyBaseElementImpl<PyNamedParameterStub
         @Contract("null -> false")
         private boolean isReferenceToParameter(@Nullable PsiElement element) {
           if (element == null) return false;
-          final PsiReference reference = element.getReference();
-          return reference != null && reference.isReferenceTo(PyNamedParameterImpl.this);
+          if (!(element instanceof PyReferenceExpression || element instanceof PyTargetExpression)) return false;
+          if (((PyQualifiedExpression)element).isQualified()) return false;
+          List<@Nullable PsiElement> definitions = PyUtil.multiResolveTopPriority(element, resolveContext);
+          return ContainerUtil.all(definitions, e -> e == PyNamedParameterImpl.this);
         }
       });
     }
diff --git a/python/testData/inspections/PyUnresolvedReferencesInspection/unionContainingUnknownType.py b/python/testData/inspections/PyUnresolvedReferencesInspection/unionContainingUnknownType.py
index e816b67e8945..daf7c3c598f7 100644
--- a/python/testData/inspections/PyUnresolvedReferencesInspection/unionContainingUnknownType.py
+++ b/python/testData/inspections/PyUnresolvedReferencesInspection/unionContainingUnknownType.py
@@ -1,4 +1,4 @@
 def foo(smth, param):
     if smth:
         param = ""
-    print(param.<weak_warning descr="Member 'str' of 'Union[{smth}, str]' does not have attribute 'smth'">smth</weak_warning>())
\ No newline at end of file
+    print(param.<weak_warning descr="Member 'str' of 'Union[str, Any]' does not have attribute 'smth'">smth</weak_warning>())
\ No newline at end of file
diff --git a/python/testSrc/com/jetbrains/python/Py3TypeTest.java b/python/testSrc/com/jetbrains/python/Py3TypeTest.java
index c83e803469a1..9e70a7af5f92 100644
--- a/python/testSrc/com/jetbrains/python/Py3TypeTest.java
+++ b/python/testSrc/com/jetbrains/python/Py3TypeTest.java
@@ -4676,6 +4676,17 @@ public class Py3TypeTest extends PyTestCase {
       """);
   }
 
+  // PY-85030
+  public void testStructuralTypesAttributeAccessAfterTypeNarrowingAndReassignmentInIf() {
+    doTest("(p: Any) -> None", """
+      def f(p):
+          if isinstance(p, int):
+              p = "foo"
+          x = p.lower()
+      expr = f
+      """);
+  }
+
   private void doTest(final String expectedType, final String text) {
     myFixture.configureByText(PythonFileType.INSTANCE, text);
     final PyExpression expr = myFixture.findElementByText("expr", PyExpression.class);
diff --git a/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
index 83f33d822696..94b28be35535 100644
--- a/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
+++ b/python/testSrc/com/jetbrains/python/inspections/Py3TypeCheckerInspectionTest.java
@@ -4125,5 +4125,37 @@ public class Py3TypeCheckerInspectionTest extends PyInspectionTestCase {
                        _: C2 = c1
                    """);
   }
+
+  // PY-85030
+  public void testStructuralTypeAndStrictUnion() {
+    doTestByText("""
+                   responses = {
+                       100: "abc",
+                   }
+                   
+                   def process(status):
+                       if isinstance(status, int):
+                           status = responses[status]
+                       return status.lower().replace(" ", "-")
+                   
+                   def do(arg):
+                       title = "abc" if arg else 100
+                       return process(title)
+                   """);
+  }
+
+  // PY-85030
+  public void testStructuralTypeAndDefiniteReassignmentUnderCondition() {
+    doTestByText("""
+                   def f(p):
+                       if p:
+                           p = "foo"
+                       else:
+                           p = "bar"
+                       return p.lower()
+                   
+                   f(42)
+                   """);
+  }
 }