diff --git a/build.sbt b/build.sbt
index 7db83017a..24d62f4c1 100644
--- a/build.sbt
+++ b/build.sbt
@@ -105,7 +105,9 @@ lazy val sharedSettings = Seq(
       Seq(
         "-Wunused:-nowarn",
         "-Wconf:cat=unused-nowarn:s",
-        "-Ywarn-unused:-nowarn"
+        "-Ywarn-unused:-nowarn",
+        "-Xmigration",
+        "-Xsource:3",
       )
     } else Seq.empty // Seq("-explain")
   },
diff --git a/modules/core/src/main/scala/gql/ast.scala b/modules/core/src/main/scala/gql/ast.scala
index f0b6537cf..1ef655edb 100644
--- a/modules/core/src/main/scala/gql/ast.scala
+++ b/modules/core/src/main/scala/gql/ast.scala
@@ -22,6 +22,7 @@ import cats.data._
 import gql.resolver._
 import java.util.UUID
 import gql.parser.{Value => V, Const}
+import scala.collection.immutable._
 
 /** A tree-like structure representing a GraphQL schema, akin to most schema builders.
   */
diff --git a/modules/core/src/main/scala/gql/dsl/FieldDsl.scala b/modules/core/src/main/scala/gql/dsl/FieldDsl.scala
index 3a4883842..33ba541da 100644
--- a/modules/core/src/main/scala/gql/dsl/FieldDsl.scala
+++ b/modules/core/src/main/scala/gql/dsl/FieldDsl.scala
@@ -21,6 +21,7 @@ import gql._
 import cats.data._
 import cats._
 import gql.dsl.aliases._
+import scala.collection.immutable._
 
 trait FieldDsl[F[_]] {
   def fields[A](hd: (String, Field[F, A, ?]), tl: (String, Field[F, A, ?])*): Fields[F, A] =
diff --git a/modules/core/src/main/scala/gql/preparation/PreparedQuery.scala b/modules/core/src/main/scala/gql/preparation/PreparedQuery.scala
index 2d198d5fa..e9bd4d090 100644
--- a/modules/core/src/main/scala/gql/preparation/PreparedQuery.scala
+++ b/modules/core/src/main/scala/gql/preparation/PreparedQuery.scala
@@ -24,6 +24,7 @@ import gql.parser.AnyValue
 import gql.Arg
 import cats.Eval
 import gql.ast
+import scala.collection.immutable._
 
 sealed trait PreparedField[+F[_], A] extends Product with Serializable