investigate issue 905

#905

build.sbt

@@ -230,6 +230,9 @@ lazy val core = project
       "org.scalatest" %% "scalatest" % "3.2.19" % Test,
       "org.sangria-graphql" %% "sangria-marshalling-testkit" % "1.0.4" % Test,
       "org.sangria-graphql" %% "sangria-spray-json" % "1.0.3" % Test,
+      "org.sangria-graphql" %% "sangria-circe" % "1.3.2" % Test,
+      "io.circe" %% "circe-parser" % "0.14.2" % Test,
+      "io.circe" %% "circe-generic" % "0.14.2" % Test,
       "org.sangria-graphql" %% "sangria-argonaut" % "1.0.2" % Test,
       "org.sangria-graphql" %% "sangria-ion" % "2.0.1" % Test,
       "eu.timepit" %% "refined" % "0.11.3" % Test,

modules/derivation/src/test/scala/test/issue-905.scala

@@ -0,0 +1,36 @@
+import io.circe.Decoder
+import sangria.schema.{InputObjectType, ObjectType}
+
+import scala.concurrent.Future
+
+case class Ctx(ctx: String)
+
+object PostSchema {
+  import sangria.marshalling.circe._
+  import io.circe.generic.semiauto._
+  import sangria.macros.derive._
+
+  case class UpdatePostGql() {
+    @GraphQLField
+    def text(text: TextInputGql): Future[String] = ???
+  }
+
+  object UpdatePostGql {
+    implicit val _ot: ObjectType[Ctx, UpdatePostGql] =
+      deriveObjectType[Ctx, UpdatePostGql](
+        ObjectTypeName("UpdatePost")
+      )
+  }
+
+  case class TextInputGql(
+      @GraphQLInputType(sangria.schema.StringType)
+      text: String)
+
+  object TextInputGql {
+    implicit val decoder: Decoder[TextInputGql] = deriveDecoder[TextInputGql]
+    implicit val _it: InputObjectType[TextInputGql] =
+      deriveInputObjectType[TextInputGql](
+        InputObjectTypeName("TextInput")
+      )
+  }
+}