feat(compiler): Reimplement noXor compiler flag [LNG-347] (#1096)

* Fix imports

* Remove constants

* Return constants

* Refactor

* Add config

* Do not propagate errors

* Do not propagate errors through on

* Rename hop ephemeral streams

* Add comments

* Add tests

api/api/.js/src/main/scala/api/AquaAPI.scala

@@ -17,7 +17,6 @@ import aqua.io.*
 import aqua.js.{FunctionDefJs, ServiceDefJs, VarJson}
 import aqua.logging.{LogFormatter, LogLevels}
 import aqua.model.AquaContext
-import aqua.model.transform.{Transform, TransformConfig}
 import aqua.parser.lexer.{LiteralToken, Token}
 import aqua.parser.{ArrowReturnError, BlockIndentError, LexerError, ParserError}
 import aqua.raw.ops.Call

api/api/.js/src/main/scala/api/types/InputTypes.scala

@@ -3,7 +3,6 @@ package api.types
 import aqua.api.AquaAPIConfig
 import aqua.api.TargetType.*
 import aqua.js.{FunctionDefJs, ServiceDefJs}
-import aqua.model.transform.TransformConfig
 
 import cats.data.Validated.{invalidNec, validNec}
 import cats.data.{Chain, NonEmptyChain, Validated, ValidatedNec}

api/api/.jvm/src/main/scala/aqua/api/Test.scala

@@ -18,9 +18,10 @@ object Test extends IOApp.Simple {
       .compilePath(
         "./aqua-src/antithesis.aqua",
         Imports.fromMap(Map("/" -> Map("" -> List("./aqua")))),
-        AquaAPIConfig(targetType = TypeScriptType),
+        AquaAPIConfig(targetType = TypeScriptType, noXor = true),
         TypeScriptBackend(false, "IFluenceClient$$")
-      ).timed
+      )
+      .timed
       .flatMap { case (duration, res) =>
         println("Compilation time: " + duration.toMillis)
         val (warnings, result) = res.value.run

api/api/src/main/scala/aqua/api/APICompilation.scala

@@ -55,14 +55,16 @@ object APICompilation {
       LogLevels.levelFromString(aquaConfig.logLevel),
       Constants.parse(aquaConfig.constants)
     ).tupled.toResult.flatTraverse { case (level, constants) =>
-      val transformConfig = aquaConfig.getTransformConfig.copy(constants = constants)
+      val transformConfig = aquaConfig.getTransformConfig
+      val config = aquaConfig.getCompilerConfig.copy(constants = constants)
 
       LogFormatter.initLogger(Some(level))
 
       new FuncCompiler[IO](
         Some(RelativePath(Path(pathStr))),
         imports.toIO,
-        transformConfig
+        transformConfig,
+        config
       ).compile().map { contextV =>
         for {
           context <- contextV.toResult
@@ -140,7 +142,7 @@ object APICompilation {
     LogFormatter.initLogger(Some(level))
 
     val transformConfig = aquaConfig.getTransformConfig
-    val config = AquaCompilerConf(constants ++ transformConfig.constantsList)
+    val config = aquaConfig.getCompilerConfig.copy(constants = constants)
 
     CompilerAPI
       .compile[IO, AquaFileError, FileModuleId, FileSpan.F](

api/api/src/main/scala/aqua/api/AquaAPIConfig.scala

@@ -1,4 +1,6 @@
 package aqua.api
+
+import aqua.compiler.AquaCompilerConf
 import aqua.model.transform.TransformConfig
 
 enum TargetType:
@@ -8,7 +10,7 @@ case class AquaAPIConfig(
   targetType: TargetType = TargetType.AirType,
   logLevel: String = "info",
   constants: List[String] = Nil,
-  noXor: Boolean = false, // TODO: Remove
+  noXor: Boolean = false,
   noRelay: Boolean = false,
   tracing: Boolean = false,
   noEmptyResponse: Boolean = true
@@ -17,10 +19,18 @@ case class AquaAPIConfig(
   def getTransformConfig: TransformConfig = {
     val config = TransformConfig(
       tracing = Option.when(tracing)(TransformConfig.TracingConfig.default),
-      noEmptyResponse = noEmptyResponse
+      noEmptyResponse = noEmptyResponse,
+      noXor = noXor
     )
 
     if (noRelay) config.copy(relayVarName = None)
     else config
   }
+
+  def getCompilerConfig: AquaCompilerConf = {
+    val config = AquaCompilerConf()
+
+    if (noRelay) config.copy(relayVarName = None)
+    else config
+  }
 }

aqua-run/src/main/scala/aqua/run/FuncCompiler.scala

@@ -22,14 +22,14 @@ import scribe.Logging
 class FuncCompiler[F[_]: Files: AquaIO: Async](
   input: Option[AquaPath],
   imports: Imports,
-  transformConfig: TransformConfig
+  transformConfig: TransformConfig,
+  config: AquaCompilerConf
 ) extends Logging {
 
   type Result = [A] =>> CompileResult[FileModuleId, AquaFileError, FileSpan.F][A]
 
   private def compileToContext(
-    path: Path,
+    path: Path
-    config: AquaCompilerConf = AquaCompilerConf(transformConfig.constantsList)
   ): F[Result[Chain[AquaContext]]] = {
     val sources = new AquaFileSources[F](path, imports)
     CompilerAPI.compileToContext[F, AquaFileError, FileModuleId, FileSpan.F](

aqua-src/antithesis.aqua

@@ -1,48 +1,15 @@
 aqua Main
 
-export bugLNG346
+export main
 
-ability Promise:
+service Srv("srv"):
-  yield() -> string
+    call(x: i32) -> i32
 
-func done_nil() -> string:
+func main(a: i32, b: i32) -> i32:
-  <- ""
+    res: *i32
+    if a > b:
+        on "peer" via "relay":
+            res <- Srv.call(a)
 
-func done() -> Promise:
-  <- Promise(yield = done_nil)
-
-ability Compute:
-  yield() -> string
-
-alias WorkerYield: -> string
-alias Yield: WorkerYield -> Promise
-
-func wait_for() -> Yield:
-  wait = func (cb: -> string) -> Promise:
-    yield = func () -> string:
-      e <- cb()
-      <- e
-    <- Promise(yield = yield)
-  <- wait
-
-ability Function:
-  run(dealId: string) -> string
-
-func simple{Compute}(yield: Yield) -> Function:
-  deal_run = func () -> string:
-    c_yield = func () -> string:
-      <- Compute.yield()
-    yieeld <- yield(c_yield)
-    res <- yieeld.yield()
-    <- res
-  <- Function(run = deal_run)
-
-func bugLNG346() -> string:
-  res: *string
-  yieeld = func () -> string:
-    res <<- "hello"
-    <- ""
-  c = Compute(yield = yieeld)
-  fn = simple{c}(wait_for())
-  r <- fn.run("")
     <- res!
+

compiler/src/main/scala/aqua/compiler/AquaCompilerConf.scala

@@ -6,5 +6,9 @@ import aqua.raw.ConstantRaw
  * What should compiler care about during compilation – before generator backend takes its role
  *
  * @param constantsList List of known constants
+ * @param relayVarName Name of the relay variable
  */
-case class AquaCompilerConf(constantsList: List[ConstantRaw])
+case class AquaCompilerConf(
+  constants: List[ConstantRaw] = Nil,
+  relayVarName: Option[String] = Some("-relay-")
+)

compiler/src/main/scala/aqua/compiler/CompilerAPI.scala

@@ -4,7 +4,7 @@ import aqua.backend.Backend
 import aqua.compiler.AquaError.*
 import aqua.model.AquaContext
 import aqua.parser.{Ast, ParserError}
-import aqua.raw.RawContext
+import aqua.raw.{ConstantRaw, RawContext}
 import aqua.semantics.header.{HeaderHandler, HeaderSem}
 import aqua.semantics.rules.locations.{DummyLocationsInterpreter, LocationsAlgebra}
 import aqua.semantics.{FileId, RawSemantics}
@@ -48,7 +48,7 @@ object CompilerAPI extends Logging {
       .implicits(
         RawContext.blank.copy(
           parts = Chain
-            .fromSeq(config.constantsList)
+            .fromSeq(config.constants ++ ConstantRaw.defaultConstants(config.relayVarName))
             .map(const => RawContext.blank -> const)
         )
       )

compiler/src/test/scala/aqua/compiler/AquaCompilerSpec.scala

@@ -883,4 +883,94 @@ class AquaCompilerSpec extends AnyFlatSpec with Matchers with Inside {
         }
       }
   }
+
+  it should "not generate error propagation in `if` with `noXor = true`" in {
+    val src = Map(
+      "index.aqua" ->
+        """aqua Test
+          |
+          |export main
+          |
+          |service Srv("srv"):
+          |  call()
+          |
+          |func main(a: i32):
+          |  if a > 0:
+          |    Srv.call()
+          |""".stripMargin
+    )
+
+    val transformCfg = TransformConfig(noEmptyResponse = true, relayVarName = None, noXor = true)
+
+    insideRes(src, transformCfg = transformCfg)("main") { case main :: Nil =>
+      val aArg = VarModel("-a-arg-", ScalarType.i32)
+      val gt = CallModel.Export("gt", ScalarType.bool)
+      val expected = XorRes.wrap(
+        SeqRes.wrap(
+          getDataSrv("a", aArg.name, aArg.baseType),
+          CallServiceRes(
+            LiteralModel.quote("cmp"),
+            "gt",
+            CallRes(aArg :: LiteralModel.number(0) :: Nil, Some(gt)),
+            initPeer
+          ).leaf,
+          XorRes.wrap(
+            MatchMismatchRes(gt.asVar, LiteralModel.bool(true), true).wrap(
+              CallServiceRes(
+                LiteralModel.quote("srv"),
+                "call",
+                CallRes(Nil, None),
+                initPeer
+              ).leaf
+            )
+          )
+        ),
+        errorCall(transformCfg, 0, initPeer)
+      )
+
+      main.body.equalsOrShowDiff(expected) should be(true)
+    }
+  }
+
+  it should "not generate error propagation in `on` with `noXor = true`" in {
+    val src = Map(
+      "index.aqua" ->
+        """aqua Test
+          |
+          |export main
+          |
+          |service Srv("srv"):
+          |  call()
+          |
+          |func main():
+          |  on "peer" via "relay":
+          |    Srv.call()
+          |  Srv.call()
+          |""".stripMargin
+    )
+
+    val transformCfg = TransformConfig(noEmptyResponse = true, relayVarName = None, noXor = true)
+
+    insideRes(src, transformCfg = transformCfg)("main") { case main :: Nil =>
+      def call(peer: ValueModel) =
+        CallServiceRes(
+          LiteralModel.quote("srv"),
+          "call",
+          CallRes(Nil, None),
+          peer
+        ).leaf
+
+      val expected = XorRes.wrap(
+        SeqRes.wrap(
+          through(LiteralModel.quote("relay")),
+          call(LiteralModel.quote("peer")),
+          through(LiteralModel.quote("relay")),
+          call(initPeer)
+        ),
+        errorCall(transformCfg, 0, initPeer)
+      )
+
+      main.body.equalsOrShowDiff(expected) should be(true)
+    }
+  }
 }

language-server/language-server-api/src/main/scala/aqua/lsp/LSPCompiler.scala

@@ -2,10 +2,11 @@ package aqua.lsp
 
 import aqua.compiler.{AquaCompiler, AquaCompilerConf, AquaError, AquaSources}
 import aqua.parser.{Ast, ParserError}
-import aqua.raw.RawContext
+import aqua.raw.{ConstantRaw, RawContext}
+import aqua.semantics.FileId
 import aqua.semantics.header.{HeaderHandler, HeaderSem}
 import aqua.semantics.rules.locations.LocationsAlgebra
-import aqua.semantics.FileId
+
 import cats.data.Validated.validNec
 import cats.data.{Chain, State, Validated, ValidatedNec}
 import cats.syntax.either.*
@@ -24,7 +25,7 @@ object LSPCompiler {
         LspContext.blank.copy(raw =
           RawContext.blank.copy(
             parts = Chain
-              .fromSeq(config.constantsList)
+              .fromSeq(config.constants ++ ConstantRaw.defaultConstants(config.relayVarName))
               .map(const => RawContext.blank -> const)
           )
         )

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

@@ -3,7 +3,7 @@ package aqua.model.inline
 import aqua.errors.Errors.internalError
 import aqua.model
 import aqua.model.*
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.ops.RawTag
 import aqua.raw.value.{ValueRaw, VarRaw}
 import aqua.types.*
@@ -27,7 +27,7 @@ import scribe.Logging
  */
 object ArrowInliner extends Logging {
 
-  def callArrow[S: Exports: Arrows: Mangler](
+  def callArrow[S: Exports: Arrows: Mangler: Config](
     arrow: FuncArrow,
     call: CallModel
   ): State[S, OpModel.Tree] =
@@ -43,7 +43,7 @@ object ArrowInliner extends Logging {
       )
 
   // push results to streams if they are exported to streams
-  private def pushStreamResults[S: Mangler: Exports: Arrows](
+  private def pushStreamResults[S: Mangler: Exports: Arrows: Config](
     outsideStreamNames: Set[String],
     exportTo: List[CallModel.Export],
     results: List[ValueRaw]
@@ -140,7 +140,7 @@ object ArrowInliner extends Logging {
   }
 
   // Apply a callable function, get its fully resolved body & optional value, if any
-  private def inline[S: Mangler: Arrows: Exports](
+  private def inline[S: Mangler: Arrows: Exports: Config](
     fn: FuncArrow,
     call: CallModel,
     outsideDeclaredStreams: Set[String]
@@ -542,7 +542,7 @@ object ArrowInliner extends Logging {
     _ <- Exports[S].resolved(exportsResolved)
   } yield (fn.copy(body = treeWithCanons, ret = ret), SeqModel.wrap(canons))
 
-  private[inline] def callArrowRet[S: Exports: Arrows: Mangler](
+  private[inline] def callArrowRet[S: Exports: Arrows: Mangler: Config](
     arrow: FuncArrow,
     call: CallModel
   ): State[S, (OpModel.Tree, List[ValueModel])] = for {

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

@@ -1,15 +1,15 @@
 package aqua.model.inline
 
+import aqua.model.*
 import aqua.model.inline.RawValueInliner.unfold
 import aqua.model.inline.raw.RawInliner
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
-import aqua.model.*
 import aqua.raw.value.MakeStructRaw
 import aqua.types.{StreamMapType, StructType}
 
 import cats.data.{Chain, NonEmptyMap, State}
-import cats.syntax.foldable.*
 import cats.syntax.bifunctor.*
+import cats.syntax.foldable.*
 import cats.syntax.functor.*
 
 object MakeStructRawInliner extends RawInliner[MakeStructRaw] {
@@ -58,7 +58,7 @@ object MakeStructRawInliner extends RawInliner[MakeStructRaw] {
     constructThroughMap(mapName, mapType, CallModel.Export(resultName, resultType), fields)
   }
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: MakeStructRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = {

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

@@ -3,7 +3,7 @@ package aqua.model.inline
 import aqua.model.*
 import aqua.model.inline.Inline.MergeMode.*
 import aqua.model.inline.raw.*
-import aqua.model.inline.state.{Arrows, Counter, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.ops.*
 import aqua.raw.value.*
 import aqua.types.{ArrayType, LiteralType, OptionType, StreamType}
@@ -23,7 +23,7 @@ object RawValueInliner extends Logging {
 
   import aqua.model.inline.Inline.*
 
-  private[inline] def unfold[S: Mangler: Exports: Arrows](
+  private[inline] def unfold[S: Mangler: Exports: Arrows: Config](
     raw: ValueRaw,
     propertiesAllowed: Boolean = true
   ): State[S, (ValueModel, Inline)] = for {
@@ -69,7 +69,7 @@ object RawValueInliner extends Logging {
     }
   } yield result
 
-  private[inline] def inlineToTree[S: Mangler: Exports: Arrows](
+  private[inline] def inlineToTree[S: Mangler: Exports: Arrows: Config](
     inline: Inline
   ): State[S, List[OpModel.Tree]] =
     (inline.mergeMode match {
@@ -77,7 +77,7 @@ object RawValueInliner extends Logging {
       case ParMode => inline.predo.toList
     }).pure
 
-  private[inline] def toModel[S: Mangler: Exports: Arrows](
+  private[inline] def toModel[S: Mangler: Exports: Arrows: Config](
     unfoldF: State[S, (ValueModel, Inline)]
   ): State[S, (ValueModel, Option[OpModel.Tree])] =
     for {
@@ -92,7 +92,7 @@ object RawValueInliner extends Logging {
       _ = logger.trace("map was: " + map)
     } yield vm -> parDesugarPrefix(ops.filterNot(_ == EmptyModel.leaf))
 
-  def valueToModel[S: Mangler: Exports: Arrows](
+  def valueToModel[S: Mangler: Exports: Arrows: Config](
     value: ValueRaw,
     propertiesAllowed: Boolean = true
   ): State[S, (ValueModel, Option[OpModel.Tree])] = for {
@@ -100,7 +100,7 @@ object RawValueInliner extends Logging {
     model <- toModel(unfold(value, propertiesAllowed))
   } yield model
 
-  def valueListToModel[S: Mangler: Exports: Arrows](
+  def valueListToModel[S: Mangler: Exports: Arrows: Config](
     values: List[ValueRaw]
   ): State[S, List[(ValueModel, Option[OpModel.Tree])]] =
     values.traverse(valueToModel(_))
@@ -109,7 +109,7 @@ object RawValueInliner extends Logging {
    * Unfold all arguments and make CallModel
    * @param flatStreamArguments canonicalize and flatten all stream arguments if true
    */
-  def callToModel[S: Mangler: Exports: Arrows](
+  def callToModel[S: Mangler: Exports: Arrows: Config](
     call: Call,
     flatStreamArguments: Boolean
   ): State[S, (CallModel, Option[OpModel.Tree])] = {
@@ -122,7 +122,7 @@ object RawValueInliner extends Logging {
           State.pure(args)
       }
       exportTo <- call.exportTo.traverse {
-        case c@Call.Export(_, _, isExistingStream) if isExistingStream =>
+        case c @ Call.Export(_, _, isExistingStream) if isExistingStream =>
           // process streams, because they can be stored in Exports outside function/closure with different name
           valueToModel(c.toRaw)
         case ce =>

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

@@ -3,8 +3,8 @@ package aqua.model.inline
 import aqua.errors.Errors.internalError
 import aqua.model.*
 import aqua.model.inline.raw.{CallArrowRawInliner, CallServiceRawInliner}
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
-import aqua.model.inline.tag.IfTagInliner
+import aqua.model.inline.tag.*
 import aqua.raw.ops.*
 import aqua.raw.value.*
 import aqua.types.{CanonStreamType, CollectionType, StreamType}
@@ -193,35 +193,16 @@ object TagInliner extends Logging {
    * @tparam S Current state
    * @return Model (if any), and prefix (if any)
    */
-  def tagToModel[S: Mangler: Arrows: Exports](
+  def tagToModel[S: Mangler: Arrows: Exports: Config](
     tag: RawTag
   ): State[S, TagInlined[S]] =
     tag match {
       case OnTag(peerId, via, strategy) =>
-        for {
+        OnTagInliner(peerId, via, strategy).inlined.map(inlined =>
-          peerIdDe <- valueToModel(peerId)
+          TagInlined.Mapping(
-          viaDe <- valueListToModel(via.toList)
+            toModel = inlined.toModel,
-          viaDeFlattened <- viaDe.traverse { case (vm, tree) =>
+            prefix = inlined.prefix
-            flat(vm, tree)
-          }
-          (pid, pif) = peerIdDe
-          (viaD, viaF) = viaDeFlattened.unzip
-            .bimap(Chain.fromSeq, _.flatten)
-          strat = strategy.map { case OnTag.ReturnStrategy.Relay =>
-            OnModel.ReturnStrategy.Relay
-          }
-          toModel = (children: Chain[OpModel.Tree]) =>
-            XorModel.wrap(
-              OnModel(pid, viaD, strat).wrap(
-                children
-              ),
-              // This will return to previous topology
-              // and propagate error up
-              FailModel(ValueModel.error).leaf
           )
-        } yield TagInlined.Mapping(
-          toModel = toModel,
-          prefix = parDesugarPrefix(viaF.prependedAll(pif))
         )
 
       case IfTag(valueRaw) =>
@@ -471,7 +452,7 @@ object TagInliner extends Logging {
       inlined <- headInlined.build(children)
     } yield inlined
 
-  def handleTree[S: Exports: Mangler: Arrows](
+  def handleTree[S: Exports: Mangler: Arrows: Config](
     tree: RawTag.Tree
   ): State[S, OpModel.Tree] =
     traverseS(tree, tagToModel(_))

model/inline/src/main/scala/aqua/model/inline/raw/ApplyBinaryOpRawInliner.scala

@@ -2,32 +2,32 @@ package aqua.model.inline.raw
 
 import aqua.errors.Errors.internalError
 import aqua.model.*
-import aqua.model.inline.raw.RawInliner
-import aqua.model.inline.TagInliner
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
-import aqua.raw.value.{AbilityRaw, LiteralRaw, MakeStructRaw}
-import cats.data.{NonEmptyList, NonEmptyMap, State}
 import aqua.model.inline.Inline
+import aqua.model.inline.Inline.MergeMode
 import aqua.model.inline.RawValueInliner.{unfold, valueToModel}
-import aqua.types.{ArrowType, ScalarType, Type}
+import aqua.model.inline.TagInliner
+import aqua.model.inline.raw.RawInliner
+import aqua.model.inline.state.*
 import aqua.raw.value.ApplyBinaryOpRaw
 import aqua.raw.value.ApplyBinaryOpRaw.Op
 import aqua.raw.value.ApplyBinaryOpRaw.Op.*
-import aqua.model.inline.Inline.MergeMode
+import aqua.raw.value.{AbilityRaw, LiteralRaw, MakeStructRaw}
+import aqua.types.LiteralType
+import aqua.types.{ArrowType, ScalarType, Type}
 
 import cats.data.Chain
-import cats.syntax.traverse.*
+import cats.data.{NonEmptyList, NonEmptyMap, State}
-import cats.syntax.monoid.*
-import cats.syntax.functor.*
-import cats.syntax.flatMap.*
-import cats.syntax.apply.*
-import cats.syntax.foldable.*
 import cats.syntax.applicative.*
-import aqua.types.LiteralType
+import cats.syntax.apply.*
+import cats.syntax.flatMap.*
+import cats.syntax.foldable.*
+import cats.syntax.functor.*
+import cats.syntax.monoid.*
+import cats.syntax.traverse.*
 
 object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: ApplyBinaryOpRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = for {
@@ -83,7 +83,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
     }
   } yield result
 
-  private def inlineEqOp[S: Mangler: Exports: Arrows](
+  private def inlineEqOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,
@@ -106,7 +106,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
     case _ => fullInlineEqOp(lmodel, rmodel, linline, rinline, op, resType)
   }
 
-  private def fullInlineEqOp[S: Mangler: Exports: Arrows](
+  private def fullInlineEqOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,
@@ -152,7 +152,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
     result(name, resType, predo)
   }
 
-  private def inlineBoolOp[S: Mangler: Exports: Arrows](
+  private def inlineBoolOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,
@@ -178,7 +178,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
     case _ => fullInlineBoolOp(lmodel, rmodel, linline, rinline, op, resType)
   }
 
-  private def fullInlineBoolOp[S: Mangler: Exports: Arrows](
+  private def fullInlineBoolOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,
@@ -230,7 +230,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
     result(name, resType, predo)
   }
 
-  private def inlineCmpOp[S: Mangler: Exports: Arrows](
+  private def inlineCmpOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,
@@ -276,7 +276,7 @@ object ApplyBinaryOpRawInliner extends RawInliner[ApplyBinaryOpRaw] {
       result(fn, resType, predo)
   }
 
-  private def inlineMathOp[S: Mangler: Exports: Arrows](
+  private def inlineMathOp[S: Mangler: Exports: Arrows: Config](
     lmodel: ValueModel,
     rmodel: ValueModel,
     linline: Inline,

model/inline/src/main/scala/aqua/model/inline/raw/ApplyFunctorRawInliner.scala

@@ -3,7 +3,7 @@ package aqua.model.inline.raw
 import aqua.model.inline.Inline
 import aqua.model.inline.Inline.MergeMode.*
 import aqua.model.inline.RawValueInliner.unfold
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.model.{
   CallModel,
   CanonicalizeModel,
@@ -24,7 +24,7 @@ import scribe.Logging
 
 object ApplyFunctorRawInliner extends Logging {
 
-  def apply[S: Mangler: Exports: Arrows](
+  def apply[S: Mangler: Exports: Arrows: Config](
     value: ValueModel,
     functor: FunctorRaw
   ): State[S, (VarModel, Inline)] = {

model/inline/src/main/scala/aqua/model/inline/raw/ApplyIntoCopyRawInliner.scala

@@ -4,10 +4,11 @@ import aqua.errors.Errors.internalError
 import aqua.model.*
 import aqua.model.inline.Inline.MergeMode.*
 import aqua.model.inline.RawValueInliner.unfold
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.model.inline.{Inline, MakeStructRawInliner}
 import aqua.raw.value.IntoCopyRaw
 import aqua.types.{StreamMapType, StructType}
+
 import cats.data.{Chain, NonEmptyMap, State}
 import cats.syntax.foldable.*
 import cats.syntax.functor.*
@@ -40,10 +41,16 @@ object ApplyIntoCopyRawInliner extends Logging {
     }
 
     MakeStructRawInliner
-      .constructThroughMap(mapName, mapType, CallModel.Export(resultName, resultType), fields, nonCopiedValues)
+      .constructThroughMap(
+        mapName,
+        mapType,
+        CallModel.Export(resultName, resultType),
+        fields,
+        nonCopiedValues
+      )
   }
 
-  def apply[S: Mangler: Exports: Arrows](
+  def apply[S: Mangler: Exports: Arrows: Config](
     value: VarModel,
     intoCopy: IntoCopyRaw
   ): State[S, (VarModel, Inline)] = {

model/inline/src/main/scala/aqua/model/inline/raw/ApplyPropertiesRawInliner.scala

@@ -6,7 +6,7 @@ import aqua.model.ValueModel.Ability
 import aqua.model.inline.Inline
 import aqua.model.inline.Inline.MergeMode.*
 import aqua.model.inline.RawValueInliner.unfold
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.value.*
 import aqua.types.*
 
@@ -24,7 +24,7 @@ import scribe.Logging
 object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Logging {
 
   // in perspective literals can have properties and functors (like `nil` with length)
-  def flatLiteralWithProperties[S: Mangler: Exports: Arrows](
+  def flatLiteralWithProperties[S: Mangler: Exports: Arrows: Config](
     literal: LiteralModel,
     inl: Inline,
     properties: Chain[PropertyModel]
@@ -45,7 +45,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
     }
   }
 
-  private def unfoldAbilityProperty[S: Mangler: Exports: Arrows](
+  private def unfoldAbilityProperty[S: Mangler: Exports: Arrows: Config](
     varModel: VarModel,
     abilityType: NamedType,
     p: PropertyRaw
@@ -112,7 +112,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
       )
   }
 
-  private[inline] def unfoldProperty[S: Mangler: Exports: Arrows](
+  private[inline] def unfoldProperty[S: Mangler: Exports: Arrows: Config](
     varModel: VarModel,
     p: PropertyRaw
   ): State[S, (VarModel, Inline)] =
@@ -172,7 +172,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
   private case class PropertyRawWithModel(raw: PropertyRaw, model: Option[PropertyModel])
 
   // Unfold properties that we can process in parallel
-  private def optimizeProperties[S: Mangler: Exports: Arrows](
+  private def optimizeProperties[S: Mangler: Exports: Arrows: Config](
     properties: Chain[PropertyRaw]
   ): State[S, (Chain[PropertyRawWithModel], Inline)] = {
     properties.map {
@@ -211,7 +211,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
     }.sequence.map(_.toList.unzip.bimap(Chain.fromSeq, _.combineAll))
   }
 
-  private def unfoldProperties[S: Mangler: Exports: Arrows](
+  private def unfoldProperties[S: Mangler: Exports: Arrows: Config](
     prevInline: Inline,
     vm: VarModel,
     properties: Chain[PropertyRaw],
@@ -263,7 +263,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
   /**
    * Unfold `stream[idx]`
    */
-  private def unfoldStreamGate[S: Mangler: Exports: Arrows](
+  private def unfoldStreamGate[S: Mangler: Exports: Arrows: Config](
     streamName: String,
     streamType: StreamType,
     idx: ValueRaw
@@ -325,7 +325,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
     mergeMode = SeqMode
   )
 
-  private def unfoldRawWithProperties[S: Mangler: Exports: Arrows](
+  private def unfoldRawWithProperties[S: Mangler: Exports: Arrows: Config](
     raw: ValueRaw,
     properties: Chain[PropertyRaw],
     propertiesAllowed: Boolean
@@ -389,7 +389,7 @@ object ApplyPropertiesRawInliner extends RawInliner[ApplyPropertyRaw] with Loggi
         flatten = VarModel(nn, varModel.`type`)
       } yield flatten -> Inline.tree(FlattenModel(varModel, flatten.name).leaf)
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     apr: ApplyPropertyRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = {

model/inline/src/main/scala/aqua/model/inline/raw/ApplyUnaryOpRawInliner.scala

@@ -1,28 +1,28 @@
 package aqua.model.inline.raw
 
 import aqua.model.*
-import aqua.model.inline.raw.RawInliner
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
-import aqua.raw.value.{AbilityRaw, LiteralRaw, MakeStructRaw}
-import cats.data.{NonEmptyList, NonEmptyMap, State}
 import aqua.model.inline.Inline
 import aqua.model.inline.RawValueInliner.{unfold, valueToModel}
-import aqua.types.{ArrowType, ScalarType}
+import aqua.model.inline.raw.RawInliner
+import aqua.model.inline.state.*
 import aqua.raw.value.ApplyUnaryOpRaw
 import aqua.raw.value.ApplyUnaryOpRaw.Op.*
+import aqua.raw.value.{AbilityRaw, LiteralRaw, MakeStructRaw}
+import aqua.types.{ArrowType, ScalarType}
 
 import cats.data.Chain
-import cats.syntax.traverse.*
+import cats.data.{NonEmptyList, NonEmptyMap, State}
-import cats.syntax.monoid.*
-import cats.syntax.functor.*
-import cats.syntax.flatMap.*
-import cats.syntax.apply.*
-import cats.syntax.foldable.*
 import cats.syntax.applicative.*
+import cats.syntax.apply.*
+import cats.syntax.flatMap.*
+import cats.syntax.foldable.*
+import cats.syntax.functor.*
+import cats.syntax.monoid.*
+import cats.syntax.traverse.*
 
 object ApplyUnaryOpRawInliner extends RawInliner[ApplyUnaryOpRaw] {
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: ApplyUnaryOpRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = for {
@@ -40,7 +40,7 @@ object ApplyUnaryOpRawInliner extends RawInliner[ApplyUnaryOpRaw] {
     }
   } yield result
 
-  private def fullInline[S: Mangler: Exports: Arrows](
+  private def fullInline[S: Mangler: Exports: Arrows: Config](
     vm: ValueModel,
     vinline: Inline,
     op: ApplyUnaryOpRaw.Op

model/inline/src/main/scala/aqua/model/inline/raw/CallArrowRawInliner.scala

@@ -3,7 +3,7 @@ package aqua.model.inline.raw
 import aqua.errors.Errors.internalError
 import aqua.model.*
 import aqua.model.inline.RawValueInliner.callToModel
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.model.inline.{ArrowInliner, Inline, RawValueInliner}
 import aqua.raw.ops.Call
 import aqua.raw.value.CallArrowRaw
@@ -14,7 +14,7 @@ import scribe.Logging
 
 object CallArrowRawInliner extends RawInliner[CallArrowRaw] with Logging {
 
-  private[inline] def unfold[S: Mangler: Exports: Arrows](
+  private[inline] def unfold[S: Mangler: Exports: Arrows: Config](
     value: CallArrowRaw,
     exportTo: List[Call.Export]
   ): State[S, (List[ValueModel], Inline)] = {
@@ -31,7 +31,7 @@ object CallArrowRawInliner extends RawInliner[CallArrowRaw] with Logging {
     resolveArrow(funcName, call)
   }
 
-  private def resolveFuncArrow[S: Mangler: Exports: Arrows](
+  private def resolveFuncArrow[S: Mangler: Exports: Arrows: Config](
     fn: FuncArrow,
     call: Call
   ): State[S, (List[ValueModel], Inline)] = {
@@ -52,7 +52,7 @@ object CallArrowRawInliner extends RawInliner[CallArrowRaw] with Logging {
     }
   }
 
-  private def resolveArrow[S: Mangler: Exports: Arrows](
+  private def resolveArrow[S: Mangler: Exports: Arrows: Config](
     funcName: String,
     call: Call
   ): State[S, (List[ValueModel], Inline)] = for {
@@ -76,7 +76,7 @@ object CallArrowRawInliner extends RawInliner[CallArrowRaw] with Logging {
       })
   } yield result
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: CallArrowRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] =

model/inline/src/main/scala/aqua/model/inline/raw/CallServiceRawInliner.scala

@@ -3,22 +3,22 @@ package aqua.model.inline.raw
 import aqua.model.*
 import aqua.model.inline.Inline
 import aqua.model.inline.RawValueInliner.{callToModel, valueToModel}
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.ops.Call
 import aqua.raw.value.CallServiceRaw
+
 import cats.data.{Chain, State}
 import scribe.Logging
 
 object CallServiceRawInliner extends RawInliner[CallServiceRaw] with Logging {
 
-  private[inline] def unfold[S: Mangler: Exports: Arrows](
+  private[inline] def unfold[S: Mangler: Exports: Arrows: Config](
     value: CallServiceRaw,
     exportTo: List[Call.Export]
   ): State[S, (List[ValueModel], Inline)] = Exports[S].exports.flatMap { exports =>
     logger.trace(s"${exportTo.mkString(" ")} $value")
     logger.trace(Console.BLUE + s"call service id ${value.serviceId}" + Console.RESET)
 
-
     val call = Call(value.arguments, exportTo)
 
     for {
@@ -40,7 +40,7 @@ object CallServiceRawInliner extends RawInliner[CallServiceRaw] with Logging {
     } yield values.values.toList -> inline
   }
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: CallServiceRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] =

model/inline/src/main/scala/aqua/model/inline/raw/CollectionRawInliner.scala

@@ -3,7 +3,7 @@ package aqua.model.inline.raw
 import aqua.model.*
 import aqua.model.inline.Inline
 import aqua.model.inline.RawValueInliner.valueToModel
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.value.CollectionRaw
 import aqua.types.StreamMapType
 import aqua.types.{ArrayType, CanonStreamType, OptionType, StreamType}
@@ -12,7 +12,7 @@ import cats.data.{Chain, State}
 
 object CollectionRawInliner extends RawInliner[CollectionRaw] {
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: CollectionRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] =

model/inline/src/main/scala/aqua/model/inline/raw/MakeAbilityRawInliner.scala

@@ -3,7 +3,7 @@ package aqua.model.inline.raw
 import aqua.model.ValueModel.Ability
 import aqua.model.inline.Inline
 import aqua.model.inline.RawValueInliner.unfold
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.model.{SeqModel, ValueModel, VarModel}
 import aqua.raw.value.AbilityRaw
 import aqua.types.AbilityType
@@ -15,7 +15,7 @@ import cats.syntax.functor.*
 
 object MakeAbilityRawInliner extends RawInliner[AbilityRaw] {
 
-  private def updateFields[S: Mangler: Exports: Arrows](
+  private def updateFields[S: Mangler: Exports: Arrows: Config](
     name: String,
     fields: NonEmptyMap[String, (ValueModel, Inline)]
   ): State[S, Unit] =
@@ -27,7 +27,7 @@ object MakeAbilityRawInliner extends RawInliner[AbilityRaw] {
         Exports[S].resolveAbilityField(name, n, vm)
     }.as(())
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: AbilityRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = {

model/inline/src/main/scala/aqua/model/inline/raw/RawInliner.scala

@@ -2,13 +2,14 @@ package aqua.model.inline.raw
 
 import aqua.model.ValueModel
 import aqua.model.inline.Inline
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.value.ValueRaw
+
 import cats.data.State
 
 trait RawInliner[T <: ValueRaw] {
 
-  def apply[S: Mangler: Exports: Arrows](
+  def apply[S: Mangler: Exports: Arrows: Config](
     raw: T,
     propertiesAllowed: Boolean = true
   ): State[S, (ValueModel, Inline)]

model/inline/src/main/scala/aqua/model/inline/raw/StreamGateInliner.scala

@@ -3,17 +3,17 @@ package aqua.model.inline.raw
 import aqua.errors.Errors.internalError
 import aqua.model.*
 import aqua.model.inline.Inline
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
 import aqua.model.inline.RawValueInliner.unfold
+import aqua.model.inline.state.*
 import aqua.types.{ArrayType, CanonStreamType, ScalarType, StreamType}
 
-import cats.data.State
 import cats.data.Chain
+import cats.data.State
+import cats.instances.stream
+import cats.syntax.applicative.*
 import cats.syntax.monoid.*
 import cats.syntax.option.*
-import cats.syntax.applicative.*
 import scribe.Logging
-import cats.instances.stream
 
 object StreamGateInliner extends Logging {
 
@@ -88,7 +88,7 @@ object StreamGateInliner extends Logging {
     )
   }
 
-  def apply[S: Mangler: Exports: Arrows](
+  def apply[S: Mangler: Exports: Arrows: Config](
     streamName: String,
     streamType: StreamType,
     sizeModel: ValueModel

model/inline/src/main/scala/aqua/model/inline/raw/StreamRawInliner.scala

@@ -3,7 +3,7 @@ package aqua.model.inline.raw
 import aqua.model.*
 import aqua.model.inline.Inline
 import aqua.model.inline.RawValueInliner.valueToModel
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.inline.state.*
 import aqua.raw.value.StreamRaw
 
 import cats.data.{Chain, State}
@@ -11,7 +11,7 @@ import cats.syntax.traverse.*
 
 object StreamRawInliner extends RawInliner[StreamRaw] {
 
-  override def apply[S: Mangler: Exports: Arrows](
+  override def apply[S: Mangler: Exports: Arrows: Config](
     raw: StreamRaw,
     propertiesAllowed: Boolean
   ): State[S, (ValueModel, Inline)] = {

model/inline/src/main/scala/aqua/model/inline/state/Config.scala

@@ -0,0 +1,41 @@
+package aqua.model.inline.state
+
+import cats.data.{Reader, State}
+
+/**
+ * Representation that `S` contains configuration for inlining
+ */
+trait Config[S] {
+  self =>
+
+  /**
+   * Flag that disables error propagation mechanics in inlined code
+   */
+  def noErrorPropagation: Reader[S, Boolean]
+
+  final def transform[R](f: R => S): Config[R] = new Config[R] {
+
+    override def noErrorPropagation: Reader[R, Boolean] =
+      self.noErrorPropagation.local(f)
+  }
+}
+
+object Config {
+  case class Values(noErrorPropagation: Boolean = false)
+
+  object Values {
+    lazy val default: Values = Values()
+  }
+
+  given Config[Values] = new Config[Values] {
+
+    override def noErrorPropagation: Reader[Values, Boolean] =
+      Reader(_.noErrorPropagation)
+  }
+
+  def apply[S: Config]: Config[S] =
+    implicitly[Config[S]]
+
+  def noErrorPropagation[S: Config]: Reader[S, Boolean] =
+    Config[S].noErrorPropagation
+}

model/inline/src/main/scala/aqua/model/inline/state/InliningState.scala

@@ -1,11 +1,12 @@
 package aqua.model.inline.state
 
 import aqua.mangler.ManglerState
-import aqua.model.{FuncArrow, ValueModel}
 import aqua.model.inline.state.{Arrows, Counter, Exports, Mangler}
+import aqua.model.{FuncArrow, ValueModel}
 import aqua.raw.arrow.FuncRaw
 import aqua.raw.value.{ValueRaw, VarRaw}
 import aqua.types.ArrowType
+
 import cats.data.{Chain, State}
 import cats.instances.list.*
 import cats.syntax.traverse.*
@@ -27,7 +28,8 @@ case class InliningState(
   noNames: ManglerState = ManglerState(),
   resolvedExports: Map[String, ValueModel] = Map.empty,
   resolvedArrows: Map[String, FuncArrow] = Map.empty,
-  instructionCounter: Int = 0
+  instructionCounter: Int = 0,
+  config: Config.Values = Config.Values.default
 )
 
 object InliningState {
@@ -44,4 +46,6 @@ object InliningState {
   given Exports[InliningState] =
     Exports.Simple.transformS(_.resolvedExports, (acc, ex) => acc.copy(resolvedExports = ex))
 
+  given Config[InliningState] =
+    Config[Config.Values].transform(_.config)
 }

model/inline/src/main/scala/aqua/model/inline/tag/IfTagInliner.scala

@@ -1,25 +1,28 @@
 package aqua.model.inline.tag
 
-import aqua.raw.value.{ApplyBinaryOpRaw, ValueRaw}
+import aqua.helpers.syntax.reader.*
-import aqua.raw.value.ApplyBinaryOpRaw.Op as BinOp
-import aqua.model.ValueModel
 import aqua.model.*
-import aqua.model.inline.state.{Arrows, Exports, Mangler}
+import aqua.model.ValueModel
+import aqua.model.inline.Inline.parDesugarPrefixOpt
 import aqua.model.inline.RawValueInliner.valueToModel
 import aqua.model.inline.TagInliner.canonicalizeIfStream
-import aqua.model.inline.Inline.parDesugarPrefixOpt
+import aqua.model.inline.state.*
-import cats.data.{Chain, State}
+import aqua.raw.value.ApplyBinaryOpRaw.Op as BinOp
-import cats.syntax.flatMap.*
+import aqua.raw.value.{ApplyBinaryOpRaw, ValueRaw}
-import cats.syntax.apply.*
+
 import cats.Eval
+import cats.data.Reader
+import cats.data.{Chain, State}
+import cats.syntax.apply.*
+import cats.syntax.flatMap.*
 
 final case class IfTagInliner(
   valueRaw: ValueRaw
 ) {
   import IfTagInliner.*
 
-  def inlined[S: Mangler: Exports: Arrows]: State[S, IfTagInlined] =
+  def inlined[S: Mangler: Exports: Arrows: Config]: State[S, IfTagInlined] = for {
-    (valueRaw match {
+    cond <- (valueRaw match {
       // Optimize in case last operation is equality check
       case ApplyBinaryOpRaw(op @ (BinOp.Eq | BinOp.Neq), left, right, _) =>
         (
@@ -41,12 +44,36 @@ final case class IfTagInliner(
 
           (prefix, valueModel, compareModel, shouldMatch)
         }
-    }).map { case (prefix, leftValue, rightValue, shouldMatch) =>
+    })
-      IfTagInlined(
+    (prefix, leftValue, rightValue, shouldMatch) = cond
+    noProp <- Config[S].noErrorPropagation.toState
+    model = if (noProp) toModelNoProp else toModel
+  } yield IfTagInlined(
     prefix,
-        toModel(leftValue, rightValue, shouldMatch)
+    model(leftValue, rightValue, shouldMatch)
+  )
+
+  private def toModelNoProp(
+    leftValue: ValueModel,
+    rightValue: ValueModel,
+    shouldMatch: Boolean
+  )(children: Chain[OpModel.Tree]): OpModel.Tree =
+    children
+      .filterNot(_.head == EmptyModel)
+      .uncons
+      .map { case (ifBody, elseBody) =>
+        XorModel.wrap(
+          MatchMismatchModel(
+            leftValue,
+            rightValue,
+            shouldMatch
+          ).wrap(ifBody),
+          SeqModel.wrap(
+            elseBody
+          )
         )
       }
+      .getOrElse(EmptyModel.leaf)
 
   private def toModel(
     leftValue: ValueModel,

model/inline/src/main/scala/aqua/model/inline/tag/OnTagInliner.scala

@@ -0,0 +1,68 @@
+package aqua.model.inline.tag
+
+import aqua.helpers.syntax.reader.*
+import aqua.model.*
+import aqua.model.inline.Inline.parDesugarPrefix
+import aqua.model.inline.RawValueInliner.{valueListToModel, valueToModel}
+import aqua.model.inline.TagInliner.flat
+import aqua.model.inline.state.*
+import aqua.raw.ops.OnTag
+import aqua.raw.value.ValueRaw
+
+import cats.data.{Chain, State}
+import cats.syntax.bifunctor.*
+import cats.syntax.traverse.*
+
+final case class OnTagInliner(
+  peerId: ValueRaw,
+  via: Chain[ValueRaw],
+  strategy: Option[OnTag.ReturnStrategy]
+) {
+  import OnTagInliner.*
+
+  def inlined[S: Mangler: Exports: Arrows: Config]: State[S, OnTagInlined] =
+    for {
+      peerIdDe <- valueToModel(peerId)
+      viaDe <- valueListToModel(via.toList)
+      viaDeFlattened <- viaDe.traverse(flat.tupled)
+      (pid, pif) = peerIdDe
+      (viaD, viaF) = viaDeFlattened.unzip.bimap(Chain.fromSeq, _.flatten)
+      strat = strategy.map { case OnTag.ReturnStrategy.Relay =>
+        OnModel.ReturnStrategy.Relay
+      }
+      noProp <- Config[S].noErrorPropagation.toState
+      model = if (noProp) toModelNoProp else toModel
+    } yield OnTagInlined(
+      prefix = parDesugarPrefix(viaF.prependedAll(pif)),
+      toModel = model(pid, viaD, strat)
+    )
+
+  private def toModelNoProp(
+    pid: ValueModel,
+    via: Chain[ValueModel],
+    strat: Option[OnModel.ReturnStrategy]
+  )(children: Chain[OpModel.Tree]): OpModel.Tree =
+    OnModel(pid, via, strat).wrap(children)
+
+  private def toModel(
+    pid: ValueModel,
+    via: Chain[ValueModel],
+    strat: Option[OnModel.ReturnStrategy]
+  )(children: Chain[OpModel.Tree]): OpModel.Tree =
+    XorModel.wrap(
+      OnModel(pid, via, strat).wrap(
+        children
+      ),
+      // This will return to previous topology
+      // and propagate error up
+      FailModel(ValueModel.error).leaf
+    )
+}
+
+object OnTagInliner {
+
+  final case class OnTagInlined(
+    prefix: Option[OpModel.Tree],
+    toModel: Chain[OpModel.Tree] => OpModel.Tree
+  )
+}

model/raw/src/main/scala/aqua/raw/ConstantRaw.scala

@@ -51,7 +51,7 @@ object ConstantRaw {
   def hostPeerId(relayVarName: Option[String]): ConstantRaw =
     ConstantRaw(
       "HOST_PEER_ID",
-      relayVarName.fold[ValueRaw](ValueRaw.InitPeerId)(r => VarRaw(r, ScalarType.string)),
+      relayVarName.fold(ValueRaw.InitPeerId)(r => VarRaw(r, ScalarType.string)),
       false
     )
 

model/res/src/main/scala/aqua/res/MakeRes.scala

@@ -1,12 +1,13 @@
 package aqua.res
 
+import aqua.model.*
+import aqua.raw.value.{LiteralRaw, ValueRaw}
+import aqua.types.*
 import aqua.types.{ArrayType, CanonStreamType, StreamType}
+
 import cats.Eval
 import cats.data.{Chain, NonEmptyList}
 import cats.free.Cofree
-import aqua.raw.value.{LiteralRaw, ValueRaw}
-import aqua.model.*
-import aqua.types.*
 
 /**
  * Helpers for translating [[OpModel]] to [[ResolvedOp]]
@@ -22,8 +23,8 @@ object MakeRes {
   def hop(onPeer: ValueModel): ResolvedOp.Tree = {
     // Those names can't be produced from compilation
     // so they are safe to use
-    val streamName = "-ephemeral-stream-"
+    val streamName = "-hop-"
-    val canonName = "-ephemeral-canon-"
+    val canonName = "-hopc-"
     val elementType = BottomType
     val streamType = StreamType(elementType)
     val canonType = CanonStreamType(elementType)

model/transform/src/main/scala/aqua/model/transform/Transform.scala

@@ -2,7 +2,7 @@ package aqua.model.transform
 
 import aqua.model.*
 import aqua.model.inline.ArrowInliner
-import aqua.model.inline.state.InliningState
+import aqua.model.inline.state.{Config, InliningState}
 import aqua.model.transform.TransformConfig.TracingConfig
 import aqua.model.transform.funcop.*
 import aqua.model.transform.pre.*
@@ -48,6 +48,7 @@ object Transform extends Logging {
   private def funcToModelTree(
     func: FuncArrow,
     preTransformer: FuncPreTransformer,
+    conf: TransformConfig,
     funcArgName: String = "_func"
   ): Eval[OpModel.Tree] = {
 
@@ -66,7 +67,10 @@ object Transform extends Logging {
     val call = CallModel(funcArg :: Nil, Nil)
 
     // <funcArgName> resolves to func
-    val initState = InliningState(resolvedArrows = Map(funcArgName -> func))
+    val initState = InliningState(
+      resolvedArrows = Map(funcArgName -> func),
+      config = Config.Values(noErrorPropagation = conf.noXor)
+    )
 
     // Inlining `funcAround(<funcArgName>)`
     ArrowInliner
@@ -118,7 +122,7 @@ object Transform extends Logging {
 
     for {
       // Pre transform and inline the function
-      model <- funcToModelTree(func, preTransformer)
+      model <- funcToModelTree(func, preTransformer, conf)
       // Post transform the function.
       // We should wrap `model` with `onInitPeer` here
       // so that TagInliner would not wrap it with `xor`.

model/transform/src/main/scala/aqua/model/transform/TransformConfig.scala

@@ -20,6 +20,7 @@ import cats.kernel.Monoid
  * @param relayVarName - name of the relay variable
  * @param tracing - tracing configuration
  * @param constants - list of constants
+ * @param noXor - if true, do not generate generate `xor`s for error propagation
  */
 case class TransformConfig(
   getDataService: String = "getDataSrv",
@@ -30,16 +31,12 @@ case class TransformConfig(
   noEmptyResponse: Boolean = false,
   relayVarName: Option[String] = Some("-relay-"),
   tracing: Option[TransformConfig.TracingConfig] = None,
-  constants: List[ConstantRaw] = Nil
+  noXor: Boolean = false
 ) {
-
   val errorId: ValueRaw = LiteralRaw.quote(errorFuncName)
   val errorHandlingSrvId: ValueRaw = LiteralRaw.quote(errorHandlingService)
   val callbackSrvId: ValueRaw = LiteralRaw.quote(callbackService)
   val dataSrvId: ValueRaw = LiteralRaw.quote(getDataService)
-
-  val constantsList: List[ConstantRaw] =
-    ConstantRaw.defaultConstants(relayVarName) ::: constants
 }
 
 object TransformConfig {

model/transform/src/main/scala/aqua/model/transform/funcop/OpTransform.scala

@@ -2,9 +2,9 @@ package aqua.model.transform.funcop
 
 import aqua.model.OpModel
 
+import cats.Eval
 import cats.data.Chain
 import cats.free.Cofree
-import cats.Eval
 
 /**
  * Base type for [[OpModel.Tree]] -> [[OpModel.Tree]] transformation
@@ -23,7 +23,7 @@ trait OpTransform {
         .lift(op, children)
         .getOrElse(
           Eval.now(
-            op.wrap(children.toList: _*)
+            op.wrap(children.toList*)
           )
         )
     )

utils/helpers/src/main/scala/aqua/helpers/syntax/reader.scala

@@ -0,0 +1,10 @@
+package aqua.helpers.syntax
+
+import cats.data.{Reader, State}
+
+object reader {
+
+  extension [S, A](r: Reader[S, A]) {
+    def toState: State[S, A] = State.inspect(r.run)
+  }
+}