diff --git a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
index a0922c1f0574..4272ed15333f 100644
--- a/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
+++ b/compiler/src/dotty/tools/dotc/core/TypeComparer.scala
@@ -1007,7 +1007,10 @@ class TypeComparer(@constructorOnly initctx: Context) extends ConstraintHandling
       case tp1: MatchType =>
         def compareMatch = tp2 match {
           case tp2: MatchType =>
-            isSameType(tp1.scrutinee, tp2.scrutinee) &&
+            def widen(tp: Type) = tp match
+              case tp: TermRef if tp.symbol.is(InlineProxy) => tp.info
+              case tp                                       => tp.widenSkolem
+            isSameType(widen(tp1.scrutinee), widen(tp2.scrutinee)) &&
             tp1.cases.corresponds(tp2.cases)(isSubType)
           case _ => false
         }
diff --git a/tests/pos/16583.scala b/tests/pos/16583.scala
new file mode 100644
index 000000000000..06f9f01b1772
--- /dev/null
+++ b/tests/pos/16583.scala
@@ -0,0 +1,19 @@
+import scala.compiletime.constValueTuple
+
+val ll0: Tuple3["one", "two", "three"] = constValueTuple[("one", "two", "three")]
+val ll1 = constValueTuple[("one", "two", "three")].toList
+val ll3: List["one" | ("two" | ("three" | Nothing))] = constValueTuple[("one", "two", "three")].toList
+val ll4: List["one" | ("two" | "three")] = constValueTuple[("one", "two", "three")].toList
+
+inline def labels[Labels <: Tuple](using ev: Tuple.Union[Labels] <:< String): List[String] =
+  val tmp = constValueTuple[Labels].toList
+  ev.substituteCo(tmp)
+
+def test = labels[("one", "two", "three")]
+
+def toList(x: Tuple): List[Tuple.Union[x.type]] = ???
+def test2[Labels <: Tuple] = toList((???): Labels)
+
+def i16654 =
+  def t1: Tuple = EmptyTuple
+  val t2 = t1.toList
diff --git a/tests/pos/16654.scala b/tests/pos/16654.scala
new file mode 100644
index 000000000000..9234c309de88
--- /dev/null
+++ b/tests/pos/16654.scala
@@ -0,0 +1,7 @@
+def toCsvFlat[A <: Product](a: A)(using m: scala.deriving.Mirror.ProductOf[A]) = {
+  def flatTuple(any: Any): Tuple = any match
+    case p: Product => p.productIterator.map(flatTuple).foldLeft(EmptyTuple: Tuple)(_ ++ _)
+    case a          => Tuple1(a)
+
+  val tuple = flatTuple(Tuple.fromProductTyped(a)).toList
+}