diff --git a/pkg/analyzer/lib/src/dart/element/least_upper_bound.dart b/pkg/analyzer/lib/src/dart/element/least_upper_bound.dart
index 27eceab..4bc97f5 100644
--- a/pkg/analyzer/lib/src/dart/element/least_upper_bound.dart
+++ b/pkg/analyzer/lib/src/dart/element/least_upper_bound.dart
@@ -667,10 +667,14 @@
       return _functionType(T1, T2);
     }
 
-    // UP(T Function<...>(...), T2) = Object
-    // UP(T1, T Function<...>(...)) = Object
-    if (T1 is FunctionType || T2 is FunctionType) {
-      return _typeSystem.objectNone;
+    // UP(T Function<...>(...), T2) = UP(Object, T2)
+    if (T1 is FunctionType) {
+      return getLeastUpperBound(_typeSystem.objectNone, T2);
+    }
+
+    // UP(T1, T Function<...>(...)) = UP(T1, Object)
+    if (T2 is FunctionType) {
+      return getLeastUpperBound(T1, _typeSystem.objectNone);
     }
 
     // UP(T1, T2) = T2 if T1 <: T2
diff --git a/pkg/analyzer/test/src/dart/element/upper_lower_bound_test.dart b/pkg/analyzer/test/src/dart/element/upper_lower_bound_test.dart
index cda9e13..3c9c633 100644
--- a/pkg/analyzer/test/src/dart/element/upper_lower_bound_test.dart
+++ b/pkg/analyzer/test/src/dart/element/upper_lower_bound_test.dart
@@ -2000,6 +2000,20 @@
       );
     }
   }
+
+  test_unrelated() {
+    var T1 = functionTypeNone(returnType: intNone);
+
+    _checkLeastUpperBound(T1, intNone, objectNone);
+    _checkLeastUpperBound(T1, intQuestion, objectQuestion);
+    _checkLeastUpperBound(T1, intStar, objectStar);
+
+    _checkLeastUpperBound(
+      T1,
+      futureOrNone(functionQuestion),
+      objectQuestion,
+    );
+  }
 }
 
 @reflectiveTest