diff --git a/modules/core/src/main/scala-2/doobie/util/GetPlatform.scala b/modules/core/src/main/scala-2/doobie/util/GetPlatform.scala
index 0274fe4d4..f543a2965 100644
--- a/modules/core/src/main/scala-2/doobie/util/GetPlatform.scala
+++ b/modules/core/src/main/scala-2/doobie/util/GetPlatform.scala
@@ -5,21 +5,17 @@
 package doobie.util
 
 import shapeless._
-import shapeless.ops.hlist.IsHCons
 
 trait GetPlatform {
-  import doobie.util.compat.=:=
 
   /** @group Instances */
-  implicit def unaryProductGet[A, L <: HList, H, T <: HList](
+  implicit def unaryProductGet[A, L <: HList, H](
       implicit
       G: Generic.Aux[A, L],
-      C: IsHCons.Aux[L, H, T],
-      H: Lazy[Get[H]],
-      E: (H :: HNil) =:= L
+      E: (H :: HNil) =:= L,
+      H: Lazy[Get[H]]
   ): MkGet[A] = {
-    void(C) // C drives inference but is not used directly
-    val get = H.value.tmap[A](h => G.from(h :: HNil))
+    val get = H.value.tmap[A](h => G.from(E.apply(h :: HNil)))
     MkGet.lift(get)
   }
 
diff --git a/modules/core/src/main/scala-2/doobie/util/PutPlatform.scala b/modules/core/src/main/scala-2/doobie/util/PutPlatform.scala
index 9b946f158..16c28f7fb 100644
--- a/modules/core/src/main/scala-2/doobie/util/PutPlatform.scala
+++ b/modules/core/src/main/scala-2/doobie/util/PutPlatform.scala
@@ -5,21 +5,17 @@
 package doobie.util
 
 import shapeless._
-import shapeless.ops.hlist.IsHCons
 
 trait PutPlatform {
-  import doobie.util.compat.=:=
 
   /** @group Instances */
-  implicit def unaryProductPut[A, L <: HList, H, T <: HList](
+  implicit def unaryProductPut[A, H, L <: HList](
       implicit
       G: Generic.Aux[A, L],
-      C: IsHCons.Aux[L, H, T],
-      H: Lazy[Put[H]],
-      E: (H :: HNil) =:= L
+      E: L =:= (H :: HNil),
+      H: Lazy[Put[H]]
   ): MkPut[A] = {
-    void(E) // E is a necessary constraint but isn't used directly
-    val put = H.value.contramap[A](a => G.to(a).head)
+    val put = H.value.contramap[A](a => E.apply(G.to(a)).head)
     MkPut.lift(put)
   }
 
diff --git a/modules/core/src/test/scala-2/doobie/util/PutSuitePlatform.scala b/modules/core/src/test/scala-2/doobie/util/PutSuitePlatform.scala
index 3237f6bf5..3d8293d26 100644
--- a/modules/core/src/test/scala-2/doobie/util/PutSuitePlatform.scala
+++ b/modules/core/src/test/scala-2/doobie/util/PutSuitePlatform.scala
@@ -4,31 +4,26 @@
 
 package doobie.util
 import doobie.testutils.{VoidExtensions, assertContains}
+import doobie.testutils.TestClasses.CCAnyVal
 
-object PutSuitePlatform {
-  final case class Y(x: String) extends AnyVal
-  final case class P(x: Int) extends AnyVal
-}
+object PutSuitePlatform {}
 
 trait PutSuitePlatform { self: munit.FunSuite =>
-  import PutSuitePlatform._
-
   test("Put can be auto derived for unary products (AnyVal)") {
     import doobie.generic.auto._
 
-    Put[Y].void
-    Put[P].void
+    Put[CCAnyVal].void
   }
 
   test("Put can be explicitly derived for unary products (AnyVal)") {
-    Put.derived[Y].void
-    Put.derived[P].void
+    Put.derived[CCAnyVal].void
   }
 
   test("Put should not be derived for non-unary products") {
     import doobie.generic.auto._
     import doobie.testutils.TestClasses.{CCIntString, PlainObj}
 
+    println(compileErrors("Put[CCIntString]"))
     assertContains(compileErrors("Put[CCIntString]"), "implicit value")
     assertContains(compileErrors("Put[(Int, Int)]"), "implicit value")
     assertContains(compileErrors("Put[PlainObj.type]"), "implicit value")
diff --git a/modules/testutils/src/test/scala/doobie/testutils/TestClasses.scala b/modules/testutils/src/test/scala/doobie/testutils/TestClasses.scala
index c39e21269..27fe46061 100644
--- a/modules/testutils/src/test/scala/doobie/testutils/TestClasses.scala
+++ b/modules/testutils/src/test/scala/doobie/testutils/TestClasses.scala
@@ -16,5 +16,7 @@ object TestClasses {
 
   case class CCIntString(i: Int, s: String)
 
+  case class CCAnyVal(s: String) extends AnyVal
+
   object PlainObj
 }