diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 325176e42..e7671abfe 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -24,7 +24,7 @@ jobs:
       fail-fast: false
       matrix:
         os: [ubuntu-latest]
-        scala: [2.12.19, 2.13.11]
+        scala: [2.12.19, 2.13.12]
         java: [adopt@1.8]
         platform: [jvm, js, native]
     runs-on: ${{ matrix.os }}
@@ -75,7 +75,7 @@ jobs:
     strategy:
       matrix:
         os: [ubuntu-latest]
-        scala: [2.13.11]
+        scala: [2.13.12]
         java: [adopt@1.8]
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/build.sbt b/build.sbt
index 195697c75..0eebf29e8 100644
--- a/build.sbt
+++ b/build.sbt
@@ -2,7 +2,7 @@ import com.github.sbt.git.SbtGit.GitKeys.*
 import sbtcrossproject.CrossProject
 
 val Scala212 = "2.12.19"
-val Scala213 = "2.13.11"
+val Scala213 = "2.13.12"
 
 commonSettings
 noPublishSettings
diff --git a/core/shared/src/main/scala/shapeless/poly.scala b/core/shared/src/main/scala/shapeless/poly.scala
index ba627fe9a..90043b95d 100644
--- a/core/shared/src/main/scala/shapeless/poly.scala
+++ b/core/shared/src/main/scala/shapeless/poly.scala
@@ -170,11 +170,11 @@ object PolyDefns extends Cases {
    * Base class for lifting a `Function1` to a `Poly1`
    */
   class ->[T, R](f : T => R) extends Poly1 {
-    implicit def subT[U <: T]: Case.Aux[U, R] = at[U](f)
+    implicit def subT[U <: T]: this.Case.Aux[U, R] = at[U](f)
   }
 
   trait LowPriorityLiftFunction1 extends Poly1 {
-    implicit def default[T]: Case.Aux[T, HNil] = at[T](_ => HNil : HNil)
+    implicit def default[T]: this.Case.Aux[T, HNil] = at[T](_ => HNil : HNil)
   }
 
   /**
@@ -182,7 +182,7 @@ object PolyDefns extends Cases {
    * its only element if the argument is in the original functions domain, `HNil` otherwise.
    */
   class >->[T, R](f : T => R) extends LowPriorityLiftFunction1 {
-    implicit def subT[U <: T]: Case.Aux[U, R :: HNil] = at[U](f(_) :: HNil)
+    implicit def subT[U <: T]: this.Case.Aux[U, R :: HNil] = at[U](f(_) :: HNil)
   }
 
   trait LowPriorityLiftU extends Poly {
@@ -210,7 +210,7 @@ object PolyDefns extends Cases {
    */
   trait ~>[F[_], G[_]] extends Poly1 {
     def apply[T](f : F[T]) : G[T]
-    implicit def caseUniv[T]: Case.Aux[F[T], G[T]] = at[F[T]](apply(_))
+    implicit def caseUniv[T]: this.Case.Aux[F[T], G[T]] = at[F[T]](apply(_))
   }
 
   object ~> {
diff --git a/project/Boilerplate.scala b/project/Boilerplate.scala
index a2b959f21..6e10748b9 100644
--- a/project/Boilerplate.scala
+++ b/project/Boilerplate.scala
@@ -388,7 +388,7 @@ object Boilerplate {
         -   object build extends Poly${arity} {
         -     val functions = self.functions
         -     implicit def allCases[${`A..N`}, Out](implicit tL: Function${arity}TypeAt[${`A..N`}, Out, HL]): Case.Aux[${`A..N`}, Out] =
-        -       at(tL(functions))
+        -       this.at(tL(functions))
         -   }
         - }
         -