remove inherited choices from Scala codegen, test interface/template IDs (#14113)

* inherited choices are gone, convert to interface
* use toInterface for conformance tests on interfaces

CHANGELOG_BEGIN
- [Scala codegen] Interface choices can no longer be invoked directly on
  template IDs, or via ``createAnd`` or ``key`` directly.  Instead, use
  ``toInterface[Ifn]`` before calling the relevant ``exercise*`` method.

  The resulting ledger commands now contain the correct interface ID
  rather than template ID for looking up the choice, but see #13993 for
  a caveat regarding create-and-exercise and exercise-by-key.
CHANGELOG_END

language-support/scala/codegen-sample-app/src/main/daml/MyMain.daml

@@ -597,11 +597,6 @@ interface InterfaceToMix where
   choice InheritedOnly: ContractId InterfaceToMix with
     controller getOwner this
     do return self
-{- TODO(#13926) uncomment when overloaded choices compile
-  choice OverloadedInTemplate: () with
-    controller getOwner this
-    do return ()
--}
 
 template InterfaceMixer with
     party: Party

language-support/scala/codegen-sample-app/src/main/daml/MyMainIface.daml

@@ -9,3 +9,7 @@ interface IfaceFromAnotherMod where
       sth: Int
     controller getOwner this
     do return $ sth + 1
+  choice OverloadedInTemplate: () with
+    controller getOwner this
+    do return ()
+

language-support/scala/codegen-sample-app/src/test/scala/com/digitalasset/codegen/GeneratedCommandsUT.scala

@@ -65,6 +65,7 @@ class GeneratedCommandsUT extends AnyWordSpec with Matchers with Inside {
     val imId: P.ContractId[MyMain.InterfaceMixer] = P.ContractId("fakeimid")
     val itmId: P.ContractId[MyMainIface.IfaceFromAnotherMod] = P.ContractId("fakeitmid")
     val DirectTemplateId = ApiTypes.TemplateId unwrap MyMain.InterfaceMixer.id
+    val ITMTemplateId = ApiTypes.TemplateId unwrap MyMain.InterfaceToMix.id
     val FAMTemplateId = ApiTypes.TemplateId unwrap MyMainIface.IfaceFromAnotherMod.id
 
     "invoke directly-defined choices" in {
@@ -82,11 +83,32 @@ class GeneratedCommandsUT extends AnyWordSpec with Matchers with Inside {
       }
     }
 
-    "invoke interface-inherited choices, directly from template" in {
-      inside(imId.exerciseInheritedOnly(alice).command.command) {
+    "invoke interface-defined choices, even when overloaded in template" in {
+      inside(
+        imId
+          .toInterface[MyMainIface.IfaceFromAnotherMod]
+          .exerciseOverloadedInTemplate(alice)
+          .command
+          .command
+      ) {
         case rpccmd.Command.Command.Exercise(
               rpccmd.ExerciseCommand(
-                Some(DirectTemplateId), // TODO(#13349, #13668) must be interface ID
+                Some(FAMTemplateId),
+                cid,
+                "OverloadedInTemplate",
+                Some(choiceArg),
+              )
+            ) =>
+          cid should ===(imId)
+          choiceArg should ===(encode(MyMainIface.OverloadedInTemplate()))
+      }
+    }
+
+    "invoke interface-inherited choices by converting to interface" in {
+      inside(imId.toInterface[MyMain.InterfaceToMix].exerciseInheritedOnly(alice).command.command) {
+        case rpccmd.Command.Command.Exercise(
+              rpccmd.ExerciseCommand(
+                Some(ITMTemplateId),
                 cid,
                 "InheritedOnly",
                 Some(choiceArg),

language-support/scala/codegen/src/main/scala/com/digitalasset/lf/codegen/CodeGen.scala

@@ -74,7 +74,7 @@ object CodeGen {
       roots: Seq[String],
   ): ValidationNel[String, Unit] =
     decodeInterfaces(files).map { interfaces: NonEmptyList[EnvironmentInterface] =>
-      val combined = interfaces.suml1.resolveChoices
+      val combined = interfaces.suml1
       val interface = combined.copy(
         typeDecls = Util.filterTemplatesBy(roots.map(_.r))(combined.typeDecls)
       )

ledger/ledger-api-tests/suites/src/main/scala/com/daml/ledger/api/testtool/suites/v1_dev/InterfaceIT.scala

@@ -16,16 +16,20 @@ import com.daml.ledger.api.testtool.infrastructure.TransactionHelpers._
 import com.daml.ledger.api.v1.value.{Identifier, Value}
 import com.daml.ledger.client.binding.Primitive
 import com.daml.ledger.test.semantic.Interface._
+import com.daml.ledger.test.semantic.{Interface1, Interface2}
 import scalaz.Tag
 
 class InterfaceIT extends LedgerTestSuite {
 
   private[this] val TId = Tag.unwrap(T.id)
-  private[this] val I1Id = Tag.unwrap(T.id).copy(moduleName = "Interface1", entityName = "I")
-  private[this] val I2Id = Tag.unwrap(T.id).copy(moduleName = "Interface2", entityName = "I")
+  private[this] val I1Id = Tag.unwrap(Interface1.I.id)
+  private[this] val I2Id = Tag.unwrap(Interface2.I.id)
 
-  // Workaround improper support of scala Codegen TODO(#13349)
-  private[this] def fixId[X](command: Primitive.Update[X], id: Identifier): Primitive.Update[X] = {
+  // replace identifier with the wrong identifier for some of these tests
+  private[this] def useWrongId[X](
+      command: Primitive.Update[X],
+      id: Identifier,
+  ): Primitive.Update[X] = {
     val exe = command.command.getExercise
     val arg = exe.getChoiceArgument.getRecord
     command
@@ -47,7 +51,7 @@ class InterfaceIT extends LedgerTestSuite {
   )(implicit ec => { case Participants(Participant(ledger, party)) =>
     for {
       t <- ledger.create(party, T(party))
-      tree <- ledger.exercise(party, x => fixId(t.exerciseMyArchive(x), TId))
+      tree <- ledger.exercise(party, x => t.exerciseMyArchive(x))
     } yield {
       val events = exercisedEvents(tree)
       assertLength(s"1 successful exercise", 1, events)
@@ -63,7 +67,7 @@ class InterfaceIT extends LedgerTestSuite {
   )(implicit ec => { case Participants(Participant(ledger, party)) =>
     for {
       t <- ledger.create(party, T(party))
-      tree <- ledger.exercise(party, x => fixId(t.exerciseMyArchive(x), I1Id))
+      tree <- ledger.exercise(party, x => t.toInterface[Interface1.I].exerciseMyArchive(x))
     } yield {
       val events = exercisedEvents(tree)
       assertLength(s"1 successful exercise", 1, events)
@@ -80,7 +84,7 @@ class InterfaceIT extends LedgerTestSuite {
     for {
       t <- ledger.create(party, T(party))
       failure <- ledger
-        .exercise(party, x => fixId(t.exerciseChoiceI1(x), TId))
+        .exercise(party, x => useWrongId(t.toInterface[Interface1.I].exerciseChoiceI1(x), TId))
         .mustFail("unknown choice")
     } yield {
       assertGrpcError(
@@ -100,7 +104,7 @@ class InterfaceIT extends LedgerTestSuite {
     for {
       t <- ledger.create(party, T(party))
       failure <- ledger
-        .exercise(party, x => fixId(t.exerciseChoiceI1(x), I2Id))
+        .exercise(party, x => useWrongId(t.toInterface[Interface1.I].exerciseChoiceI1(x), I2Id))
         .mustFail("unknown choice")
     } yield {
       assertGrpcError(