diff --git a/core/src/test/scala/splain/builtin/BasicSpec.scala b/core/src/test/scala/splain/builtin/BasicSpec.scala
index d2a19ca..49f35aa 100644
--- a/core/src/test/scala/splain/builtin/BasicSpec.scala
+++ b/core/src/test/scala/splain/builtin/BasicSpec.scala
@@ -10,6 +10,10 @@ class BasicSpec extends SpecBase.Direct with BasicFixture {
 
   check(LongArg)
 
+  describe("#34") {
+    check(compoundDiff, numberOfErrors = 0)
+  }
+
   describe("#111") {
 
     check(LongRefined)
diff --git a/core/src/testFixtures/scala/splain/builtin/BasicFixture.scala b/core/src/testFixtures/scala/splain/builtin/BasicFixture.scala
index cf796d4..9438521 100644
--- a/core/src/testFixtures/scala/splain/builtin/BasicFixture.scala
+++ b/core/src/testFixtures/scala/splain/builtin/BasicFixture.scala
@@ -45,6 +45,21 @@ object Long {
 }
 """
 
+  final val compoundDiff =
+    """
+object Compound {
+  trait T
+  type F[A] = A
+  def x[A](y: A): F[A with T] = y.asInstanceOf[A with T]
+  def f[A](a: A with String): F[A] = a
+  val y: F[Int with T] = x(x(1))
+  f(y)
+
+  val z: Int with T = x(x(1))
+  f(z)
+}
+    """
+
   final val LongRefined =
     """
 object Long {
diff --git a/testing/acceptance/src/test/scala/splain/acceptance/builtin/StaticBasicSpec.scala b/testing/acceptance/src/test/scala/splain/acceptance/builtin/StaticBasicSpec.scala
index 9c1cb04..595d0a1 100644
--- a/testing/acceptance/src/test/scala/splain/acceptance/builtin/StaticBasicSpec.scala
+++ b/testing/acceptance/src/test/scala/splain/acceptance/builtin/StaticBasicSpec.scala
@@ -16,6 +16,10 @@ class StaticBasicSpec extends Acceptance.SpecBase {
 
   check(LongArg)
 
+  describe("#34") {
+    check(compoundDiff, numberOfErrors = 0)
+  }
+
   describe("#111") {
 
     check(LongRefined)