fix(compiler): Fix nested abilities [fixes LNG-220] (#852)

* Fix fields gathering

* Remove println

* Add test

* Remove println

* Add comments

* Add comments

model/inline/src/main/scala/aqua/model/inline/ArrowInliner.scala

@@ -5,11 +5,13 @@ import aqua.model.*
 import aqua.model.inline.state.{Arrows, Exports, Mangler}
 import aqua.raw.ops.RawTag
 import aqua.raw.value.{ValueRaw, VarRaw}
-import aqua.types.{AbilityType, ArrowType, BoxType, StreamType}
+import aqua.types.{AbilityType, ArrowType, BoxType, StreamType, Type}
+
 import cats.data.{Chain, IndexedStateT, State}
 import cats.syntax.bifunctor.*
 import cats.syntax.foldable.*
 import cats.syntax.traverse.*
+import cats.syntax.option.*
 import cats.{Eval, Monoid}
 import scribe.Logging
 
@@ -117,24 +119,23 @@ object ArrowInliner extends Logging {
       exports <- Exports[S].exports
       arrows <- Arrows[S].arrows
       // gather all arrows and variables from abilities
-      returnedFromAbilities = rets.collect { case VarModel(name, st @ AbilityType(_, _), _) =>
-        getVarsAndArrowsFromAbilities(name, None, st, exports, arrows)
-      }.foldMapA(_.bimap(_.toList, _.toList)).bimap(_.toMap, _.toMap)
+      returnedAbilities = rets.collect { case VarModel(name, at: AbilityType, _) => name -> at }
+      varsFromAbilities = returnedAbilities.flatMap { case (name, at) =>
+        getAbilityVars(name, None, at, exports)
+      }.toMap
+      arrowsFromAbilities = returnedAbilities.flatMap { case (name, at) =>
+        getAbilityArrows(name, None, at, exports, arrows)
+      }.toMap
 
       // find and get resolved arrows if we return them from the function
-      returnedArrows = rets.collect { case VarModel(name, ArrowType(_, _), _) =>
-        name
-      }.toSet
+      returnedArrows = rets.collect { case VarModel(name, _: ArrowType, _) => name }.toSet
       arrowsToSave <- Arrows[S].pickArrows(returnedArrows)
-    } yield {
-      val (valsFromAbilities, arrowsFromAbilities) = returnedFromAbilities
-      InlineResult(
-        SeqModel.wrap(ops.reverse: _*),
-        rets.reverse,
-        valsFromAbilities,
-        arrowsFromAbilities ++ arrowsToSave
-      )
-    }
+    } yield InlineResult(
+      SeqModel.wrap(ops.reverse),
+      rets.reverse,
+      varsFromAbilities,
+      arrowsFromAbilities ++ arrowsToSave
+    )
 
   /**
    * Get all arrows that is arguments from outer Arrows.
@@ -271,75 +272,108 @@ object ArrowInliner extends Logging {
         AbilityType.fullName(name, n) -> AbilityType.fullName(newName, n)
       }
       allNewNames = newFieldsName.add((name, newName)).toSortedMap
-    } yield {
-      val (allVars, allArrows) =
-        getVarsAndArrowsFromAbilities(vm.name, Option(newName), t, exports, arrows)
-      AbilityResolvingResult(allNewNames, allVars, allArrows)
+      allVars = getAbilityVars(vm.name, newName.some, t, exports)
+      allArrows = getAbilityArrows(vm.name, newName.some, t, exports, arrows)
+    } yield AbilityResolvingResult(allNewNames, allVars, allArrows)
+  }
+
+  /**
+   * Get ability fields (vars or arrows) from exports
+   *
+   * @param abilityName ability current name in state
+   * @param abilityNewName ability new name (for renaming)
+   * @param abilityType ability type
+   * @param exports exports state to resolve fields
+   * @param fields fields selector
+   * @return resolved ability fields (renamed if necessary)
+   */
+  private def getAbilityFields[T <: Type](
+    abilityName: String,
+    abilityNewName: Option[String],
+    abilityType: AbilityType,
+    exports: Map[String, ValueModel]
+  )(fields: AbilityType => Map[String, T]): Map[String, ValueModel] =
+    fields(abilityType).flatMap { case (fName, _) =>
+      val fullName = AbilityType.fullName(abilityName, fName)
+      val newFullName = AbilityType.fullName(abilityNewName.getOrElse(abilityName), fName)
+
+      Exports
+        .getLastValue(fullName, exports)
+        .map(newFullName -> _)
+    }
+
+  /**
+   * Get ability vars and arrows as vars from exports
+   *
+   * @param abilityName ability current name in state
+   * @param abilityNewName ability new name (for renaming)
+   * @param abilityType ability type
+   * @param exports exports state to resolve fields
+   * @return resolved ability vars and arrows as vars (renamed if necessary)
+   */
+  private def getAbilityVars(
+    abilityName: String,
+    abilityNewName: Option[String],
+    abilityType: AbilityType,
+    exports: Map[String, ValueModel]
+  ): Map[String, ValueModel] = {
+    val get = getAbilityFields(
+      abilityName,
+      abilityNewName,
+      abilityType,
+      exports
+    )
+
+    get(_.variables) ++ get(_.arrows).flatMap {
+      case arrow @ (_, vm: VarModel) =>
+        arrow.some
+      case (_, m) =>
+        logger.error(s"Unexpected: '$m' cannot be an arrow")
+        None
     }
   }
 
   /**
-   * Gather all arrows and variables from abilities recursively (because of possible nested abilities).
-   * Rename top names if needed in gathered fields and arrows.
-   * `top` name is a first name, i.e.: `topName.fieldName`.
-   * Only top name must be renamed to keep all field names unique.
-   * @param topOldName old name to find all fields in states
-   * @param topNewName new name to rename all fields in states
-   * @param abilityType type of current ability
-   * @param exports where to get values
-   * @param arrows where to get arrows
-   * @return
+   * Get ability arrows from arrows
+   *
+   * @param abilityName ability current name in state
+   * @param abilityNewName ability new name (for renaming)
+   * @param abilityType ability type
+   * @param exports exports state to resolve fields
+   * @param arrows arrows state to resolve arrows
+   * @return resolved ability arrows (renamed if necessary)
    */
-  private def getVarsAndArrowsFromAbilities(
-    topOldName: String,
-    topNewName: Option[String],
+  private def getAbilityArrows(
+    abilityName: String,
+    abilityNewName: Option[String],
     abilityType: AbilityType,
     exports: Map[String, ValueModel],
     arrows: Map[String, FuncArrow]
-  ): (Map[String, ValueModel], Map[String, FuncArrow]) = {
-    abilityType.fields.toSortedMap.toList.map { case (fName, fValue) =>
-      val currentOldName = AbilityType.fullName(topOldName, fName)
-      // for all nested fields, arrows and abilities only left side must be renamed
-      val currentNewName = topNewName.map(AbilityType.fullName(_, fName))
-      fValue match {
-        case nestedAbilityType @ AbilityType(_, _) =>
-          getVarsAndArrowsFromAbilities(
-            currentOldName,
-            currentNewName,
-            nestedAbilityType,
-            exports,
-            arrows
-          )
-        case ArrowType(_, _) =>
-          Exports
-            .getLastValue(currentOldName, exports)
-            .flatMap {
-              case vm @ VarModel(name, _, _) =>
-                arrows
-                  .get(name)
-                  .map(fa =>
-                    (
-                      Map(currentNewName.getOrElse(currentOldName) -> vm),
-                      Map(name -> fa)
-                    )
-                  )
-              case lm @ LiteralModel(_, _) =>
-                logger.error(s"Unexpected. Literal '$lm' cannot be an arrow")
-                None
-            }
-            .getOrElse((Map.empty, Map.empty))
+  ): Map[String, FuncArrow] = {
+    val get = getAbilityFields(
+      abilityName,
+      abilityNewName,
+      abilityType,
+      exports
+    )
 
-        case _ =>
-          Exports
-            .getLastValue(currentOldName, exports)
-            .map { vm =>
-              (Map(currentNewName.getOrElse(currentOldName) -> vm), Map.empty)
-            }
-            .getOrElse((Map.empty, Map.empty))
-      }
-    }.foldMapA(_.bimap(_.toList, _.toList)).bimap(_.toMap, _.toMap)
+    get(_.arrows).flatMap {
+      case (_, VarModel(name, _, _)) =>
+        arrows.get(name).map(name -> _)
+      case (_, m) =>
+        logger.error(s"Unexpected: '$m' cannot be an arrow")
+        None
+    }
   }
 
+  private def getAbilityArrows[S: Arrows: Exports](
+    abilityName: String,
+    abilityType: AbilityType
+  ): State[S, Map[String, FuncArrow]] = for {
+    exports <- Exports[S].exports
+    arrows <- Arrows[S].arrows
+  } yield getAbilityArrows(abilityName, None, abilityType, exports, arrows)
+
   /**
    * Prepare the state context for this function call
    *
@@ -435,25 +469,6 @@ object ArrowInliner extends Logging {
       // Result could be renamed; take care about that
     } yield (tree, fn.ret.map(_.renameVars(shouldRename)))
 
-  private def getAllArrowsFromAbility[S: Exports: Arrows: Mangler](
-    name: String,
-    sc: AbilityType
-  ): State[S, Map[String, FuncArrow]] = {
-    for {
-      exports <- Exports[S].exports
-      arrows <- Arrows[S].arrows
-    } yield {
-      sc.fields.toSortedMap.toList.flatMap {
-        case (n, ArrowType(_, _)) =>
-          exports.get(AbilityType.fullName(name, n)).flatMap {
-            case VarModel(n, _, _) => arrows.get(n).map(n -> _)
-            case _ => None
-          }
-        case _ => None
-      }.toMap
-    }
-  }
-
   private[inline] def callArrowRet[S: Exports: Arrows: Mangler](
     arrow: FuncArrow,
     call: CallModel
@@ -461,8 +476,8 @@ object ArrowInliner extends Logging {
     for {
       passArrows <- Arrows[S].pickArrows(call.arrowArgNames)
       arrowsFromAbilities <- call.abilityArgs
-        .traverse(getAllArrowsFromAbility)
-        .map(_.fold(Map.empty)(_ ++ _))
+        .traverse(getAbilityArrows.tupled)
+        .map(_.flatMap(_.toList).toMap)
 
       exports <- Exports[S].exports
       streams <- getOutsideStreamNames

model/inline/src/test/scala/aqua/model/inline/ArrowInlinerSpec.scala

@@ -3,7 +3,7 @@ package aqua.model.inline
 import aqua.model.*
 import aqua.model.inline.state.InliningState
 import aqua.raw.ops.*
-import aqua.raw.value.{ApplyPropertyRaw, FunctorRaw, IntoFieldRaw, IntoIndexRaw, LiteralRaw, VarRaw}
+import aqua.raw.value.*
 import aqua.types.*
 import cats.syntax.show.*
 import cats.syntax.option.*
@@ -49,7 +49,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
       records: *string
       cb(records)
    */
-  "arrow inliner" should "pass stream to callback properly" in {
+  it should "pass stream to callback properly" in {
     val streamType = StreamType(ScalarType.string)
     val streamVar = VarRaw("records", streamType)
     val streamModel = VarModel("records", StreamType(ScalarType.string))
@@ -141,7 +141,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
       records: *string
       cb(records!)
    */
-  ignore /*"arrow inliner"*/ should "pass stream with gate to callback properly" in {
+  ignore /*it*/ should "pass stream with gate to callback properly" in {
     val streamType = StreamType(ScalarType.string)
     val streamVar = VarRaw("records", streamType)
     val streamVarLambda =
@@ -242,7 +242,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
         append_records(records)
         <- records
    */
-  "arrow inliner" should "work with streams as arguments" in {
+  it should "work with streams as arguments" in {
 
     val returnType = ArrayType(ArrayType(ScalarType.string))
     val streamType = StreamType(ArrayType(ScalarType.string))
@@ -338,7 +338,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   retval = res1 + res2 + res3
    *   <- retval
    */
-  "arrow inliner" should "leave meta after function inlining" in {
+  it should "leave meta after function inlining" in {
     val innerName = "inner"
     val innerRes = VarRaw("res", ScalarType.u16)
 
@@ -475,7 +475,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   retval = inner() + inner() + 37
    *   <- retval
    */
-  "arrow inliner" should "omit meta if arrow was completely erased" in {
+  it should "omit meta if arrow was completely erased" in {
     val innerName = "inner"
     val innerRes = VarRaw("res", ScalarType.u16)
     val innerRet = "42"
@@ -753,7 +753,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   retval = 37 + c(1) + c(2)
    *   <- retval
    */
-  "arrow inliner" should "leave meta after returned closure inlining" in {
+  it should "leave meta after returned closure inlining" in {
     val innerName = "inner"
     val closureName = "closure"
     val outterClosureName = "c"
@@ -853,7 +853,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   retval = 37 + c() + c()
    *   <- retval
    */
-  "arrow inliner" should "omit meta if returned closure was completely erased" in {
+  it should "omit meta if returned closure was completely erased" in {
     val innerName = "inner"
     val closureName = "closure"
 
@@ -1023,7 +1023,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   retval = 37 + a(1) + b(2) + c{3}
    *   <- retval
    */
-  "arrow inliner" should "correctly inline renamed closure [bug LNG-193]" in {
+  it should "correctly inline renamed closure [bug LNG-193]" in {
     val innerName = "inner"
     val closureName = "closure"
     val outterClosureName = "c"
@@ -1151,7 +1151,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   resT <- accept_closure(closure)
    *   <- resT
    */
-  "arrow inliner" should "correctly handle closure as argument [bug LNG-92]" in {
+  it should "correctly handle closure as argument [bug LNG-92]" in {
     val acceptName = "accept_closure"
     val closureName = "closure"
     val testName = "test"
@@ -1274,7 +1274,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
    *   method = "method"
    *   test(method)
    */
-  "arrow inliner" should "not rename service call [bug LNG-199]" in {
+  it should "not rename service call [bug LNG-199]" in {
     val testName = "test"
     val argMethodName = "method"
     val serviceName = "Test"
@@ -1381,7 +1381,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
      v = arg.value
      OpHa.identity(v)
    */
-  "arrow inliner" should "hold lambda" in {
+  it should "hold lambda" in {
     val innerName = "inner"
 
     // lambda that will be assigned to another variable
@@ -1485,7 +1485,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
   func joinIdxLocal(idx: i16, nodes: []string):
     join nodes[idx]
    */
-  "arrow inliner" should "not rename value in index array lambda" in {
+  it should "not rename value in index array lambda" in {
     val innerName = "inner"
 
     // lambda that will be assigned to another variable
@@ -1575,7 +1575,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
 
   }
 
-  "arrow inliner" should "rename value in arrow with same name as in for" in {
+  it should "rename value in arrow with same name as in for" in {
     val argVar = VarRaw("arg", ScalarType.u32)
     val iVar = VarRaw("i", ScalarType.string)
     val iVar0 = VarRaw("i-0", ScalarType.string)
@@ -1665,7 +1665,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
       get() -> string
 
   func inner() -> string:
-      results <- DTGetter.get_dt()
+      results <- Get.get()
       <- results
 
   func outer() -> []string:
@@ -1673,7 +1673,7 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
       results <- use_name1()
       <- results
    */
-  "arrow inliner" should "generate result in right order" in {
+  it should "generate result in right order" in {
     val innerName = "inner"
     val results = VarRaw("results", ScalarType.string)
     val resultsOut = VarRaw("results", StreamType(ScalarType.string))
@@ -1744,4 +1744,210 @@ class ArrowInlinerSpec extends AnyFlatSpec with Matchers {
     ) should be(true)
   }
 
+  /**
+   * ability Inner:
+   *     arrow(x: i8) -> bool
+   *     field: i8
+   *
+   * ability Outer:
+   *     inner: Inner
+   *
+   * func accept{Outer}() -> bool:
+   *     res = Outer.inner.arrow(Outer.inner.field)
+   *     <- res
+   *
+   * func main() -> bool:
+   *     closure = (x: i8) -> bool:
+   *         res = x > 0
+   *         <- res
+   *     inner = Inner(arrow = closure, field = 42)
+   *     outer = Outer(inner = inner)
+   *     res <- accept{outer}()
+   *     <- res
+   */
+  it should "handle nested abilities" in {
+    val arrowType = ArrowType(
+      ProductType(ScalarType.i8 :: Nil),
+      ProductType(ScalarType.bool :: Nil)
+    )
+    val closureType = arrowType.copy(
+      domain = ProductType.labelled(
+        "x" -> ScalarType.i8 :: Nil
+      )
+    )
+    val resVar = VarRaw("res", ScalarType.bool)
+    val innerType = AbilityType(
+      "Inner",
+      NonEmptyMap.of(
+        "arrow" -> arrowType,
+        "field" -> ScalarType.i8
+      )
+    )
+    val outerType = AbilityType(
+      "Outer",
+      NonEmptyMap.of(
+        "inner" -> innerType
+      )
+    )
+
+    val acceptBody = SeqTag.wrap(
+      AssignmentTag(
+        ApplyPropertyRaw.fromChain(
+          VarRaw("Outer", outerType),
+          Chain(
+            IntoFieldRaw("inner", innerType),
+            IntoArrowRaw(
+              "arrow",
+              arrowType,
+              List(
+                ApplyPropertyRaw.fromChain(
+                  VarRaw("Outer", outerType),
+                  Chain(
+                    IntoFieldRaw("inner", innerType),
+                    IntoFieldRaw("field", ScalarType.i8)
+                  )
+                )
+              )
+            )
+          )
+        ),
+        resVar.name
+      ).leaf,
+      ReturnTag(NonEmptyList.one(resVar)).leaf
+    )
+
+    val accept = FuncArrow(
+      "accept",
+      acceptBody,
+      ArrowType(
+        ProductType.labelled("Outer" -> outerType :: Nil),
+        ProductType(ScalarType.bool :: Nil)
+      ),
+      resVar :: Nil,
+      Map.empty,
+      Map.empty,
+      None
+    )
+
+    val closureBody = SeqTag.wrap(
+      AssignmentTag(
+        CallArrowRaw.service(
+          "cmp",
+          LiteralRaw.quote("cmp"),
+          "gt",
+          ArrowType(
+            ProductType(ScalarType.i64 :: ScalarType.i64 :: Nil),
+            ProductType(ScalarType.bool :: Nil)
+          ),
+          List(
+            VarRaw("x", ScalarType.i8),
+            LiteralRaw.number(0)
+          )
+        ),
+        "res"
+      ).leaf,
+      ReturnTag(NonEmptyList.one(resVar)).leaf
+    )
+
+    val mainBody = SeqTag.wrap(
+      ClosureTag(
+        FuncRaw(
+          name = "closure",
+          arrow = ArrowRaw(
+            `type` = closureType,
+            ret = resVar :: Nil,
+            body = closureBody
+          )
+        ),
+        detach = true
+      ).leaf,
+      AssignmentTag(
+        AbilityRaw(
+          NonEmptyMap.of(
+            "arrow" -> VarRaw("closure", closureType),
+            "field" -> LiteralRaw.number(42)
+          ),
+          innerType
+        ),
+        "inner"
+      ).leaf,
+      AssignmentTag(
+        AbilityRaw(
+          NonEmptyMap.of(
+            "inner" -> VarRaw("inner", innerType)
+          ),
+          outerType
+        ),
+        "outer"
+      ).leaf,
+      CallArrowRawTag
+        .func(
+          "accept",
+          Call(
+            VarRaw("outer", outerType) :: Nil,
+            Call.Export(resVar.name, resVar.`type`) :: Nil
+          )
+        )
+        .leaf,
+      ReturnTag(NonEmptyList.one(resVar)).leaf
+    )
+
+    val main = FuncArrow(
+      "main",
+      mainBody,
+      ArrowType(
+        ProductType(Nil),
+        ProductType(ScalarType.bool :: Nil)
+      ),
+      resVar :: Nil,
+      Map("accept" -> accept),
+      Map.empty,
+      None
+    )
+
+    val model = ArrowInliner
+      .callArrow[InliningState](
+        FuncArrow(
+          "wrapper",
+          CallArrowRawTag
+            .func(
+              "main",
+              Call(Nil, Nil)
+            )
+            .leaf,
+          ArrowType(
+            ProductType(Nil),
+            ProductType(Nil)
+          ),
+          Nil,
+          Map("main" -> main),
+          Map.empty,
+          None
+        ),
+        CallModel(Nil, Nil)
+      )
+      .runA(InliningState())
+      .value
+
+    val body = SeqModel.wrap(
+      SeqModel.wrap(
+        FlattenModel(LiteralModel.number(42), "literal_ap").leaf,
+        FlattenModel(VarModel("literal_ap", LiteralType.unsigned), "literal_props").leaf
+      ),
+      CallServiceModel(
+        LiteralModel.quote("cmp"),
+        "gt",
+        CallModel(
+          VarModel("literal_props", LiteralType.unsigned) :: LiteralModel.number(0) :: Nil,
+          CallModel.Export("gt", ScalarType.bool) :: Nil
+        )
+      ).leaf
+    )
+
+    val expected = List("main", "accept", "closure").foldRight(body) { case (name, body) =>
+      MetaModel.CallArrowModel(name).wrap(body)
+    }
+
+    model.equalsOrShowDiff(expected) shouldEqual true
+  }
 }

types/src/main/scala/aqua/types/Type.scala

@@ -2,6 +2,10 @@ package aqua.types
 
 import cats.PartialOrder
 import cats.data.NonEmptyMap
+import cats.Eval
+import cats.syntax.traverse.*
+import cats.syntax.applicative.*
+import cats.syntax.option.*
 
 sealed trait Type {
 
@@ -252,18 +256,69 @@ case class StructType(name: String, fields: NonEmptyMap[String, Type])
 // Ability is an unordered collection of labelled types and arrows
 case class AbilityType(name: String, fields: NonEmptyMap[String, Type]) extends NamedType {
 
-  lazy val arrows: Map[String, ArrowType] = fields.toNel.collect {
-    case (name, at @ ArrowType(_, _)) => (name, at)
-  }.toMap
+  /**
+   * Get all arrows defined in this ability and its sub-abilities.
+   * Paths to arrows are returned **without** ability name
+   * to allow renaming on call site.
+   */
+  lazy val arrows: Map[String, ArrowType] = {
+    def getArrowsEval(path: Option[String], ability: AbilityType): Eval[List[(String, ArrowType)]] =
+      ability.fields.toNel.toList.flatTraverse {
+        case (abName, abType: AbilityType) =>
+          val newPath = path.fold(abName)(AbilityType.fullName(_, abName))
+          getArrowsEval(newPath.some, abType)
+        case (aName, aType: ArrowType) =>
+          val newPath = path.fold(aName)(AbilityType.fullName(_, aName))
+          List(newPath -> aType).pure
+        case _ => Nil.pure
+      }
 
-  lazy val abilities: List[(String, AbilityType)] = fields.toNel.collect {
-    case (name, at @ AbilityType(_, _)) => (name, at)
+    getArrowsEval(None, this).value.toMap
   }
 
-  lazy val variables: List[(String, Type)] = fields.toNel.filter {
-    case (_, AbilityType(_, _)) => false
-    case (_, ArrowType(_, _)) => false
-    case (_, _) => true
+  /**
+   * Get all abilities defined in this ability and its sub-abilities.
+   * Paths to abilities are returned **without** ability name
+   * to allow renaming on call site.
+   */
+  lazy val abilities: Map[String, AbilityType] = {
+    def getAbilitiesEval(
+      path: Option[String],
+      ability: AbilityType
+    ): Eval[List[(String, AbilityType)]] =
+      ability.fields.toNel.toList.flatTraverse {
+        case (abName, abType: AbilityType) =>
+          val fullName = path.fold(abName)(AbilityType.fullName(_, abName))
+          getAbilitiesEval(fullName.some, abType).map(
+            (fullName -> abType) :: _
+          )
+        case _ => Nil.pure
+      }
+
+    getAbilitiesEval(None, this).value.toMap
+  }
+
+  /**
+   * Get all variables defined in this ability and its sub-abilities.
+   * Paths to variables are returned **without** ability name
+   * to allow renaming on call site.
+   */
+  lazy val variables: Map[String, DataType] = {
+    def getVariablesEval(
+      path: Option[String],
+      ability: AbilityType
+    ): Eval[List[(String, DataType)]] =
+      ability.fields.toNel.toList.flatTraverse {
+        case (abName, abType: AbilityType) =>
+          val newPath = path.fold(abName)(AbilityType.fullName(_, abName))
+          getVariablesEval(newPath.some, abType)
+        case (dName, dType: DataType) =>
+          val newPath = path.fold(dName)(AbilityType.fullName(_, dName))
+          List(newPath -> dType).pure
+        case _ => Nil.pure
+      }
+
+    getVariablesEval(None, this).value.toMap
   }
 
   override def toString: String =