diff --git a/build.sbt b/build.sbt
index 3f0935cc..3b043ebe 100644
--- a/build.sbt
+++ b/build.sbt
@@ -14,8 +14,8 @@ val shapelessVersion = "2.3.7"
 val scalaCheckVersion = "1.15.2"
 
 val Scala_2_11 = "2.11.12"
-val Scala_2_12 = "2.12.8"
-val Scala_2_13 = "2.13.1"
+val Scala_2_12 = "2.12.14"
+val Scala_2_13 = "2.13.8"
 
 /// sbt-github-actions configuration
 
diff --git a/src/test/scala/singleton/ops/RequireSpec.scala b/src/test/scala/singleton/ops/RequireSpec.scala
index 81d44ac9..7656a444 100644
--- a/src/test/scala/singleton/ops/RequireSpec.scala
+++ b/src/test/scala/singleton/ops/RequireSpec.scala
@@ -24,7 +24,19 @@ class RequireSpec extends Properties("Require") {
       implicit def ev(implicit r : RequireMsg[False, Testing123]) :
       TestRequireMsg = new TestRequireMsg {}
     }
+
+    trait Foo {
+      trait FF[T]
+    }
+
+    object TestFoo extends Foo {
+
+      implicit def ev[T](implicit r: RequireMsg[False, Testing123]): Set[FF[T]] = ???
+    }
+
     illTyped("""implicitly[TestRequireMsg]""","Testing 123")
+    illTyped("implicitly[Set[TestFoo.FF[Int]]]", "Testing 123")
+    illTyped("""implicitly[Set[Int]]""","could not find implicit value.*")
 
     @scala.annotation.implicitNotFound("Not replaced")
     trait TestRequireMsgSymNotReplaced
diff --git a/src/test/scala/singleton/twoface/CheckedCharSpec.scala b/src/test/scala/singleton/twoface/CheckedCharSpec.scala
index 41e39519..38141f7a 100644
--- a/src/test/scala/singleton/twoface/CheckedCharSpec.scala
+++ b/src/test/scala/singleton/twoface/CheckedCharSpec.scala
@@ -20,8 +20,8 @@ class CheckedCharSpec extends Properties("Checked.Char") {
   property("Compile-time checks") = wellTyped {
     smallerThan50('\u0020')
     smallerThan50(TwoFace.Char('\u0020'))
-    illTyped("""smallerThan50('\u0032')""")
-    illTyped("""smallerThan50(TwoFace.Char('\u0032'))""")
+    illTyped("smallerThan50('\\u0032')")
+    illTyped("smallerThan50(TwoFace.Char('\u0032'))")
   }
 
   property("Run-time checks") = wellTyped {