Remove damlLfInstantiate in favor of TypeCon.instantiate (#7166)

fixes #2506

Judging from the issue this was originally introduced to workaround a
bug. I couldn’t actually track down what that bug was but at this
point they are identical so no point keeping this around.

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ledger-service/lf-value-json/src/main/scala/com/digitalasset/daml/lf/value/json/ApiCodecCompressed.scala

@@ -288,10 +288,8 @@ class ApiCodecCompressed[Cid](val encodeDecimalAsString: Boolean, val encodeInt6
         jsValueToApiPrimitive(value, prim, defs)
       case typeCon: Model.DamlLfTypeCon =>
         val id = typeCon.name.identifier
-        // val dt = typeCon.instantiate(defs(id).getOrElse(deserializationError(s"Type $id not found")))
-        val dt = Model.damlLfInstantiate(
-          typeCon,
-          defs(id).getOrElse(deserializationError(s"Type $id not found")))
+        val dt =
+          typeCon.instantiate(defs(id).getOrElse(deserializationError(s"Type $id not found")))
         jsValueToApiDataType(value, id, dt, defs)
       case Model.DamlLfTypeNumeric(scale) =>
         val numericOrError = value match {
@@ -314,10 +312,7 @@ class ApiCodecCompressed[Cid](val encodeDecimalAsString: Boolean, val encodeInt6
       id: Model.DamlLfIdentifier,
       defs: Model.DamlLfTypeLookup): V[Cid] = {
     val typeCon = Model.DamlLfTypeCon(Model.DamlLfTypeConName(id), ImmArraySeq())
-    // val dt = typeCon.instantiate(defs(id).getOrElse(deserializationError(s"Type $id not found")))
-    val dt = Model.damlLfInstantiate(
-      typeCon,
-      defs(id).getOrElse(deserializationError(s"Type $id not found")))
+    val dt = typeCon.instantiate(defs(id).getOrElse(deserializationError(s"Type $id not found")))
     jsValueToApiDataType(value, id, dt, defs)
   }
 

ledger-service/lf-value-json/src/main/scala/com/digitalasset/daml/lf/value/json/NavigatorModelAliases.scala

@@ -67,28 +67,6 @@ trait NavigatorModelAliases[Cid] {
   type DamlLfEnum = iface.Enum
   val DamlLfEnum = iface.Enum
 
-  def damlLfInstantiate(typeCon: DamlLfTypeCon, defn: DamlLfDefDataType): DamlLfDataType =
-    if (defn.typeVars.length != typeCon.typArgs.length) {
-      throw new RuntimeException(
-        s"Mismatching type vars and applied types, expected ${defn.typeVars} but got ${typeCon.typArgs} types")
-    } else {
-      if (defn.typeVars.isEmpty) { // optimization
-        defn.dataType
-      } else {
-        val paramsMap = Map(defn.typeVars.zip(typeCon.typArgs): _*)
-        def mapTypeVars(typ: DamlLfType, f: DamlLfTypeVar => DamlLfType): DamlLfType = typ match {
-          case t @ DamlLfTypeVar(_) => f(t)
-          case t @ DamlLfTypeCon(_, _) => DamlLfTypeCon(t.name, t.typArgs.map(mapTypeVars(_, f)))
-          case t @ DamlLfTypePrim(_, _) => DamlLfTypePrim(t.typ, t.typArgs.map(mapTypeVars(_, f)))
-          case t @ DamlLfTypeNumeric(_) => t
-        }
-        val withTyp: iface.Type => iface.Type = { typ =>
-          mapTypeVars(typ, v => paramsMap.getOrElse(v.name, v))
-        }
-        defn.dataType.bimap(withTyp, withTyp)
-      }
-    }
-
   import scala.language.higherKinds
   type OfCid[F[_]] = F[Cid]
   type ApiValue = OfCid[V]

navigator/backend/src/main/scala/com/digitalasset/navigator/console/Pretty.scala

@@ -136,8 +136,7 @@ object Pretty {
       } else {
         // Once a type is instantiated, do not instantiate it in any child node.
         // Required to prevent infinite expansion of recursive types.
-        // val dt = typeCon.instantiate(typeDefs(id).get)
-        val dt = model.damlLfInstantiate(typeCon, typeDefs(id).get)
+        val dt = typeCon.instantiate(typeDefs(id).get)
         (
           Some(typeCon.name.identifier.qualifiedName.name.toString),
           damlLfDataType(dt, typeDefs, doNotExpand + id))

navigator/backend/src/main/scala/com/digitalasset/navigator/query/filter/package.scala

@@ -44,7 +44,7 @@ package object filter {
       parameter match {
         case tc: DamlLfTypeCon =>
           val nextOrResult =
-            (ps(tc.name.identifier).map(damlLfInstantiate(tc, _)), cursor.next) match {
+            (ps(tc.name.identifier).map(tc.instantiate(_)), cursor.next) match {
               case (Some(DamlLfRecord(fields)), Some(nextCursor)) =>
                 fields
                   .collectFirst {

navigator/backend/src/main/scala/com/digitalasset/navigator/query/project/package.scala

@@ -61,8 +61,7 @@ object project {
             ddt <- ps(tc.name.identifier)
               .toRight(UnknownType(tc.name.identifier.toString, cursor, value))
             nextCursor <- cursor.next.toRight(MustNotBeLastPart("DataType", cursor, value))
-            //nextField   <- tc.instantiate(ddt) match {
-            nextField <- damlLfInstantiate(tc, ddt) match {
+            nextField <- tc.instantiate(ddt) match {
               case DamlLfRecord(fields) =>
                 fields
                   .find(f => f._1 == nextCursor.current)