diff --git a/compiler/src/dotty/tools/dotc/core/TypeOps.scala b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
index e8e59252ed7d..889cf6953e37 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeOps.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeOps.scala
@@ -641,6 +641,9 @@ object TypeOps:
           if (maximize) lo else hi
 
       def apply(tp: Type): Type = tp match {
+        case _: MatchType =>
+          tp // break cycles
+
         case tp: TypeRef if isBounds(tp.underlying) =>
           val lo = this(tp.info.loBound)
           val hi = this(tp.info.hiBound)
diff --git a/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala b/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
index 70026a6b60d9..035d19b7bf9e 100644
--- a/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
+++ b/compiler/src/dotty/tools/dotc/transform/TypeTestsCasts.scala
@@ -81,6 +81,8 @@ object TypeTestsCasts {
     /** Approximate type parameters depending on variance */
     def stripTypeParam(tp: Type)(implicit ctx: Context) = new ApproximatingTypeMap {
       def apply(tp: Type): Type = tp match {
+        case _: MatchType =>
+          tp // break cycles
         case tp: TypeRef if isBounds(tp.underlying) =>
           val lo = apply(tp.info.loBound)
           val hi = apply(tp.info.hiBound)
diff --git a/tests/pos/8905-2.scala b/tests/pos/8905-2.scala
new file mode 100644
index 000000000000..78c642eca9cc
--- /dev/null
+++ b/tests/pos/8905-2.scala
@@ -0,0 +1,3 @@
+class Test[T1 <: Tuple, T2 <: Tuple] {
+  def test6[Y <: Int, X <: Function1[Tuple.Concat[T1, T2], Unit]](x: X) = x.isInstanceOf[Function1[Int, Any]]
+}
diff --git a/tests/pos/8905.scala b/tests/pos/8905.scala
new file mode 100644
index 000000000000..aed2152d8695
--- /dev/null
+++ b/tests/pos/8905.scala
@@ -0,0 +1,4 @@
+object Test {
+  def f[T1 <: Tuple](o: Option[Tuple.Concat[T1, T1]]): Unit =
+    o match { case Some(x) => }
+}