scala 3 compiles?

build.sbt

@@ -33,8 +33,8 @@ lazy val weaverVersion = "0.8.4"
 ThisBuild / tlBaseVersion := "1.0"
 ThisBuild / tlCiReleaseBranches := Seq("main") // publish snapshots on `main`
 ThisBuild / tlCiScalafmtCheck := true
-ThisBuild / scalaVersion := scala212Version
-//ThisBuild / scalaVersion := scala3Version
+//ThisBuild / scalaVersion := scala212Version
+ThisBuild / scalaVersion := scala3Version
 ThisBuild / crossScalaVersions := Seq(scala212Version, scala213Version, scala3Version)
 ThisBuild / developers += tlGitHubDev("tpolecat", "Rob Norris")
 ThisBuild / tpolecatDefaultOptionsMode :=

modules/core/src/main/scala-3/doobie/util/MkReadPlatform.scala

@@ -6,7 +6,6 @@ package doobie.util
 
 import scala.deriving.Mirror
 import doobie.util.shapeless.OrElse
-import shapeless.OrElse
 
 trait MkReadPlatform:
 
@@ -26,12 +25,13 @@ trait MkReadPlatform:
       using H: Read[H] `OrElse` Derived[MkRead[H]]
   ): Derived[MkRead[H *: EmptyTuple]] = {
     val headInstance = H.fold(identity, _.instance)
-    new Derived(new MkRead(
-      Read.Composite(
-        List(headInstance),
-        list => list(0).asInstanceOf[H] *: EmptyTuple
-      )
-    ))
+    new Derived(
+      new MkRead(
+        Read.Composite(
+          List(headInstance),
+          list => list(0).asInstanceOf[H] *: EmptyTuple
+        )
+      ))
   }
 
   // Derivation inductive case for tuples

modules/core/src/main/scala-3/doobie/util/ReadPlatform.scala

@@ -4,15 +4,22 @@
 
 package doobie.util
 
-import scala.deriving.Mirror
-
 trait ReadPlatform extends LowestPriorityRead:
-
-  // FIXME: needs to define both base case and inductive
-  given derivedTuple[P <: Tuple, A](
+
+  given tupleBase[H](
+      using H: Read[H]
+  ): Read[H *: EmptyTuple] =
+    Read.Composite(
+      List(H),
+      list => list(0).asInstanceOf[H] *: EmptyTuple
+    )
+
+  given tuple[H, T <: Tuple](
       using
-      m: Mirror.ProductOf[P],
-      i: A =:= m.MirroredElemTypes,
-      w: Read[A]
-  ): Read[P] =
-    MkRead.derived[P, A]
+      H: Read[H],
+      T: Read[T]
+  ): Read[H *: T] =
+    Read.Composite(
+      List(H, T),
+      list => list(0).asInstanceOf[H] *: list(1).asInstanceOf[T]
+    )

modules/core/src/main/scala-3/doobie/util/WritePlatform.scala

@@ -4,15 +4,26 @@
 
 package doobie.util
 
-import scala.deriving.Mirror
-
 trait WritePlatform extends LowestPriorityWrite:
 
-  // FIXME: needs to define both base case and inductive
-  given derivedTuple[P <: Tuple, A](
+  given tupleBase[H](
+      using H: Write[H]
+  ): Write[H *: EmptyTuple] =
+    Write.Composite[H *: EmptyTuple](
+      List(H),
+      {
+        case h *: EmptyTuple => List(h)
+      }
+    )
+
+  given tuple[H, T <: Tuple](
       using
-      m: Mirror.ProductOf[P],
-      i: m.MirroredElemTypes =:= A,
-      w: Write[A]
-  ): Write[P] =
-    MkWrite.derived[P, A]
+      H: Write[H],
+      T: Write[T]
+  ): Write[H *: T] =
+    Write.Composite(
+      List(H, T),
+      {
+        case h *: t => List(h, t)
+      }
+    )

modules/core/src/main/scala/doobie/util/read.scala

@@ -14,6 +14,7 @@ import doobie.free.resultset as IFRS
 import java.sql.ResultSet
 import scala.annotation.implicitNotFound
 
+/*
 @implicitNotFound("""
 Cannot find or construct a Read instance for type:
 
@@ -44,6 +45,7 @@ and similarly with Get:
 And find the missing instance and construct it as needed. Refer to Chapter 12
 of the book of doobie for more information.
 """)
+*/
 sealed trait Read[A] {
   def unsafeGet(rs: ResultSet, startIdx: Int): A
   def gets: List[(Get[?], NullabilityKnown)]
@@ -146,7 +148,7 @@ trait LowestPriorityRead {
 
 final class MkRead[A](val underlying: Read[A]) extends Read[A] {
   override def unsafeGet(rs: ResultSet, startIdx: Int): A = underlying.unsafeGet(rs, startIdx)
-  override def gets: List[(Get[_], NullabilityKnown)] = underlying.gets
+  override def gets: List[(Get[?], NullabilityKnown)] = underlying.gets
   override def toOpt: Read[Option[A]] = underlying.toOpt
   override def length: Int = underlying.length
 }

modules/core/src/test/scala-2/doobie/util/GetSuitePlatform.scala

@@ -9,7 +9,7 @@ import doobie.testutils.TestClasses.{CCIntString, PlainObj, CCAnyVal}
 trait GetSuitePlatform { self: munit.FunSuite =>
 
   test("Get can be auto derived for unary products (AnyVal)") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Get[CCAnyVal].void
   }
@@ -19,7 +19,7 @@ trait GetSuitePlatform { self: munit.FunSuite =>
   }
 
   test("Get should not be derived for non-unary products") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     assertContains(compileErrors("Get[CCIntString]"), "implicit value")
     assertContains(compileErrors("Get[(Int, Int)]"), "implicit value")

modules/core/src/test/scala-2/doobie/util/PutSuitePlatform.scala

@@ -8,7 +8,7 @@ import doobie.testutils.TestClasses.{CCIntString, PlainObj, CCAnyVal}
 
 trait PutSuitePlatform { self: munit.FunSuite =>
   test("Put can be auto derived for unary products (AnyVal)") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Put[CCAnyVal].void
   }
@@ -18,7 +18,7 @@ trait PutSuitePlatform { self: munit.FunSuite =>
   }
 
   test("Put should not be derived for non-unary products") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     assertContains(compileErrors("Put[CCIntString]"), "implicit value")
     assertContains(compileErrors("Put[(Int, Int)]"), "implicit value")

modules/core/src/test/scala-3/doobie/util/PutSuitePlatform.scala

@@ -12,7 +12,7 @@ trait PutSuitePlatform { self: munit.FunSuite =>
   test("Put should be derived for unary products (AnyVal)".ignore) {}
 
   test("Put should not be derived for non-unary products") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
     import doobie.testutils.TestClasses.{CCIntString, PlainObj}
 
     assertContains(compileErrors("Put[CCIntString]"), "No given instance")

modules/core/src/test/scala-3/doobie/util/QueryLogSuitePlatform.scala

@@ -7,7 +7,7 @@ package doobie.util
 import doobie.util.log.{Parameters, Success, ProcessingFailure}
 
 trait QueryLogSuitePlatform { self: QueryLogSuite =>
-  import doobie.generic.auto.*
+  import doobie.generic.auto.{given, *}
 
   test("[Query] n-arg success") {
     val Sql = "select 1 where ? = ?"

modules/core/src/test/scala-3/doobie/util/ReadSuitePlatform.scala

@@ -15,15 +15,15 @@ trait ReadSuitePlatform { self: munit.FunSuite =>
   case class CaseClassWithFieldWithoutGetInstance(a: String, b: NoGetInstanceForThis)
 
   test("Read should exist for some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Read[Woozle].void
     Read[(Woozle, String)].void
     Read[(Int, Woozle *: Woozle *: String *: EmptyTuple)].void
   }
 
   test("Read should exist for option of some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Read[Option[Woozle]].void
     Read[Option[(Woozle, String)]].void

modules/core/src/test/scala-3/doobie/util/WriteSuitePlatform.scala

@@ -15,15 +15,15 @@ trait WriteSuitePlatform { self: munit.FunSuite =>
   case class CaseClassWithFieldWithoutPutInstance(a: String, b: NoPutInstanceForThis)
 
   test("Write should exist for some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Woozle].void
     Write[(Woozle, String)].void
     Write[(Int, Woozle *: Woozle *: String *: EmptyTuple)].void
   }
 
   test("Write should exist for option of some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Option[Woozle]].void
     Write[Option[(Woozle, String)]].void

modules/core/src/test/scala/doobie/issue/780.scala

@@ -11,7 +11,7 @@ import scala.annotation.nowarn
 
 @nowarn("msg=.*(Foo is never used|(U|u)nused).*")
 class `780` extends munit.FunSuite {
-  import doobie.generic.auto.*
+  import doobie.generic.auto.{given, *}
 
   test("deriving instances should work correctly for Write from class scope") {
     class Foo[A: Write, B: Write] {

modules/core/src/test/scala/doobie/util/GetSuite.scala

@@ -23,7 +23,7 @@ class GetSuite extends munit.FunSuite with GetSuitePlatform {
   }
 
   test("Get should be auto derived for unary products") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Get[X].void
     Get[Q].void

modules/core/src/test/scala/doobie/util/PutSuite.scala

@@ -35,7 +35,7 @@ class PutSuite extends munit.FunSuite with PutSuitePlatform {
   }
 
   test("Put should be auto derived for unary products") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Put[X].void
     Put[Q].void

modules/core/src/test/scala/doobie/util/ReadSuite.scala

@@ -25,7 +25,7 @@ class ReadSuite extends munit.FunSuite with ReadSuitePlatform {
   )
 
   test("Read should exist for some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Read[Int].void
     Read[(Int, Int)].void
@@ -55,7 +55,7 @@ class ReadSuite extends munit.FunSuite with ReadSuitePlatform {
   }
 
   test("Read is still auto derived for tuples when import is present (no ambiguous implicits)") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
     Read[(Int, Int)].void
     Read[(Int, Int, String)].void
     Read[(Int, (Int, String))].void
@@ -111,7 +111,7 @@ class ReadSuite extends munit.FunSuite with ReadSuitePlatform {
   }
 
   test("Read should exist for option of some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Read[Option[Int]].void
     Read[Option[(Int, Int)]].void
@@ -123,14 +123,14 @@ class ReadSuite extends munit.FunSuite with ReadSuitePlatform {
   }
 
   test("Read should exist for option of Unit") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Read[Option[Unit]].void
     assertEquals(Read[Option[(Int, Unit)]].length, 1).void
   }
 
   test("Read should select multi-column instance by default") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     assertEquals(Read[LenStr1].length, 2).void
   }

modules/core/src/test/scala/doobie/util/WriteSuite.scala

@@ -30,7 +30,7 @@ class WriteSuite extends munit.FunSuite with WriteSuitePlatform {
   }
 
   test("Write should exist for some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Int].void
     Write[(Int, Int)].void
@@ -51,7 +51,7 @@ class WriteSuite extends munit.FunSuite with WriteSuitePlatform {
   }
 
   test("Write is still auto derived for tuples when import is present (no ambiguous implicits) ") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
     Write[(Int, Int)].void
     Write[(Int, Int, String)].void
     Write[(Int, (Int, String))].void
@@ -128,14 +128,14 @@ class WriteSuite extends munit.FunSuite with WriteSuitePlatform {
   }
 
   test("Write should exist for Unit") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Unit].void
     assertEquals(Write[(Int, Unit)].length, 1)
   }
 
   test("Write should exist for option of some fancy types") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Option[Int]].void
     Write[Option[(Int, Int)]].void
@@ -145,14 +145,14 @@ class WriteSuite extends munit.FunSuite with WriteSuitePlatform {
   }
 
   test("Write should exist for option of Unit") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     Write[Option[Unit]].void
     assertEquals(Write[Option[(Int, Unit)]].length, 1)
   }
 
   test("Write should select multi-column instance by default") {
-    import doobie.generic.auto.*
+    import doobie.generic.auto.{given, *}
 
     assertEquals(Write[LenStr1].length, 2)
   }

modules/fixme/src/main/scala/Fixme.scala

@@ -0,0 +1,24 @@
+package fixme
+
+import doobie.util.*
+
+case class CC(i: Option[Int], s: String, os: Option[String])
+
+case class KK(sc: CC, osc: Option[CC], i: Option[Int], s: String)
+
+object Fixme {
+  Read.derived[CC]
+
+  def lol = {
+    import doobie.generic.auto.{*, given}
+
+    {
+      MkRead.derived[CC, (Option[Int], String, Option[String])]
+      Read.fromDerived[CC]
+      summon[Read[CC]]
+      Write[CC]
+      Read[KK]
+      Write[KK]
+    }
+  }
+}