diff --git a/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetReader.scala b/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetReader.scala
index 023d785..fe3fdb5 100644
--- a/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetReader.scala
+++ b/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetReader.scala
@@ -11,7 +11,7 @@ import zio.stream._
 
 import scala.annotation.nowarn
 
-trait ParquetReader[A <: Product] {
+trait ParquetReader[+A <: Product] {
 
   def read(path: Path): ZStream[Scope, Throwable, A]
 
diff --git a/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetWriter.scala b/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetWriter.scala
index fc7fed2..fe78778 100644
--- a/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetWriter.scala
+++ b/modules/core/src/main/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetWriter.scala
@@ -12,7 +12,7 @@ import org.apache.parquet.schema.{ MessageType, Type }
 import zio._
 import zio.schema.Schema
 
-trait ParquetWriter[A <: Product] {
+trait ParquetWriter[-A <: Product] {
 
   def write(data: Chunk[A]): Task[Unit]
 
diff --git a/modules/core/src/test/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetIOSpec.scala b/modules/core/src/test/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetIOSpec.scala
index d652802..8613c89 100644
--- a/modules/core/src/test/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetIOSpec.scala
+++ b/modules/core/src/test/scala/me/mnedokushev/zio/apache/parquet/core/hadoop/ParquetIOSpec.scala
@@ -37,7 +37,7 @@ object ParquetIOSpec extends ZIOSpecDefault {
           reader <- ZIO.service[ParquetReader[Record]]
           _      <- writer.write(payload)
           _      <- writer.close // force to flush parquet data on disk
-          result <- ZIO.scoped(reader.read(tmpPath).runCollect)
+          result <- ZIO.scoped[Any](reader.read(tmpPath).runCollect)
         } yield assertTrue(result == payload)
       }.provide(
         ParquetWriter.configured[Record](tmpPath),