diff --git a/compiler/src/dotty/tools/dotc/typer/Typer.scala b/compiler/src/dotty/tools/dotc/typer/Typer.scala
index 03d33f330927..4fbeb406351d 100644
--- a/compiler/src/dotty/tools/dotc/typer/Typer.scala
+++ b/compiler/src/dotty/tools/dotc/typer/Typer.scala
@@ -1593,7 +1593,11 @@ class Typer extends Namer
     val seenParents = mutable.Set[Symbol]()
 
     def typedParent(tree: untpd.Tree): Tree = {
-      var result = if (tree.isType) typedType(tree)(superCtx) else typedExpr(tree)(superCtx)
+      def isTreeType(t: untpd.Tree): Boolean = t match {
+        case _: untpd.Apply => false
+        case _ => true
+      }
+      var result = if (isTreeType(tree)) typedType(tree)(superCtx) else typedExpr(tree)(superCtx)
       val psym = result.tpe.dealias.typeSymbol
       if (seenParents.contains(psym) && !cls.isRefinementClass) {
         if (!ctx.isAfterTyper) ctx.error(i"$psym is extended twice", tree.sourcePos)
diff --git a/tests/neg/parser-stability-25.scala b/tests/neg/parser-stability-25.scala
new file mode 100644
index 000000000000..23db4498af0e
--- /dev/null
+++ b/tests/neg/parser-stability-25.scala
@@ -0,0 +1,15 @@
+class A extends (Int => i1) // error
+class B extends (Int => this) // error
+trait C {
+  val bar: Int => this // error
+}
+
+// Test that function types ending in SIP-23 singleton types are understood correctly.
+
+class D extends (Int => 1) {
+  def apply(x: Int) = 2 // error
+}
+
+class Wrap(x: Int)
+class E extends (Wrap)( // error
+// error
\ No newline at end of file
diff --git a/tests/neg/parser-stability-26.scala b/tests/neg/parser-stability-26.scala
new file mode 100644
index 000000000000..dd2c00d5c5b9
--- /dev/null
+++ b/tests/neg/parser-stability-26.scala
@@ -0,0 +1,2 @@
+// Test that function types ending in SIP-23 singleton types are understood correctly.
+class E extends (Int => 1) // error
diff --git a/tests/neg/parser-stability-27.scala b/tests/neg/parser-stability-27.scala
new file mode 100644
index 000000000000..ed841d95c08b
--- /dev/null
+++ b/tests/neg/parser-stability-27.scala
@@ -0,0 +1,2 @@
+class F extends (Int => 1)( // error
+// error
\ No newline at end of file
diff --git a/tests/pos/singleton-fun-types.scala b/tests/pos/singleton-fun-types.scala
new file mode 100644
index 000000000000..dd2f8525c9c4
--- /dev/null
+++ b/tests/pos/singleton-fun-types.scala
@@ -0,0 +1,4 @@
+trait C extends (Int => 1)
+class D extends (Int => 1) {
+  def apply(x: Int) = 1
+}