From 74d02e1f63766ffc0f849f3d6e262030bc0deab8 Mon Sep 17 00:00:00 2001
From: Dima <dmitry.shakhtarin@fluence.ai>
Date: Thu, 7 Dec 2023 19:06:51 +0700
Subject: [PATCH] feat(language-server): Pass token types to LSP [LNG-285]
 (#999)

---
 .github/workflows/snapshot.yml                |   4 +-
 .../main/scala/aqua/run/FuncCompiler.scala    |  22 +-
 aqua-src/antithesis.aqua                      |  23 +-
 build.sbt                                     |   2 +-
 integration-tests/package.json                |   2 +-
 .../.js/src/main/scala/aqua/lsp/AquaLSP.scala | 192 +-----------
 .../src/main/scala/aqua/lsp/OutputTypes.scala |  86 ++++++
 .../main/scala/aqua/lsp/ResultHelper.scala    | 135 +++++++++
 .../src/main/scala/aqua/lsp/LSPCompiler.scala |   9 +-
 .../scala/aqua/lsp/LocationsInterpreter.scala |  63 ++--
 .../src/main/scala/aqua/lsp/LspContext.scala  |  39 ++-
 .../main/scala/aqua/lsp/LspSemantics.scala    |   5 +-
 .../src/test/scala/aqua/lsp/AquaLSPSpec.scala | 281 ++++++++++++++++++
 .../language-server-npm/aqua-lsp-api.d.ts     |   8 +-
 .../scala/aqua/tree/TreeNodeCompanion.scala   |   8 +-
 parser/src/main/scala/aqua/parser/Ast.scala   |   2 +-
 .../scala/aqua/parser/lexer/PropertyOp.scala  |   2 +-
 .../main/scala/aqua/parser/lexer/Token.scala  |   2 -
 .../scala/aqua/parser/lift/FileSpan.scala     |   9 +
 .../src/main/scala/aqua/semantics/Prog.scala  |   8 -
 .../aqua/semantics/expr/AbilitySem.scala      |   2 +-
 .../aqua/semantics/expr/DataStructSem.scala   |   2 +-
 .../aqua/semantics/expr/ServiceSem.scala      |   2 +-
 .../aqua/semantics/expr/func/ArrowSem.scala   |   3 -
 .../aqua/semantics/expr/func/CatchSem.scala   |   2 -
 .../expr/func/DeclareStreamSem.scala          |   5 -
 .../expr/func/ElseOtherwiseSem.scala          |   1 -
 .../aqua/semantics/expr/func/IfSem.scala      |   1 -
 .../aqua/semantics/expr/func/TrySem.scala     |   1 -
 .../aqua/semantics/rules/ValuesAlgebra.scala  |   2 -
 .../abilities/AbilitiesInterpreter.scala      |  14 +-
 .../definitions/DefinitionsAlgebra.scala      |   2 +-
 .../definitions/DefinitionsInterpreter.scala  |  26 +-
 .../locations/DummyLocationsInterpreter.scala |  18 +-
 .../rules/locations/LocationsAlgebra.scala    |  21 +-
 .../rules/locations/LocationsState.scala      |  55 +++-
 .../rules/locations/VariableInfo.scala        |  11 +
 .../rules/names/NamesInterpreter.scala        |  17 +-
 .../rules/types/TypesInterpreter.scala        |  24 +-
 types/src/main/scala/aqua/types/Type.scala    |  51 +++-
 .../main/scala/aqua/helpers/syntax/list.scala |  19 ++
 .../aqua/{ => helpers}/syntax/optiont.scala   |   0
 .../scala/aqua/{ => helpers}/tree/Tree.scala  |  10 +-
 43 files changed, 771 insertions(+), 420 deletions(-)
 create mode 100644 language-server/language-server-api/.js/src/main/scala/aqua/lsp/OutputTypes.scala
 create mode 100644 language-server/language-server-api/.js/src/main/scala/aqua/lsp/ResultHelper.scala
 create mode 100644 language-server/language-server-api/src/test/scala/aqua/lsp/AquaLSPSpec.scala
 create mode 100644 semantics/src/main/scala/aqua/semantics/rules/locations/VariableInfo.scala
 create mode 100644 utils/helpers/src/main/scala/aqua/helpers/syntax/list.scala
 rename utils/helpers/src/main/scala/aqua/{ => helpers}/syntax/optiont.scala (100%)
 rename utils/helpers/src/main/scala/aqua/{ => helpers}/tree/Tree.scala (79%)

diff --git a/.github/workflows/snapshot.yml b/.github/workflows/snapshot.yml
index c1653c37..7148b443 100644
--- a/.github/workflows/snapshot.yml
+++ b/.github/workflows/snapshot.yml
@@ -78,12 +78,12 @@ jobs:
           registry-url: "https://npm.fluence.dev"
           cache: "pnpm"
 
-      - run: pnpm -r i
+      - run: pnpm --filter='!integration-tests' -r i
 
       - name: Set package version
         run: node ci.cjs bump-version ${{ steps.version.outputs.id }}
 
-      - run: pnpm -r build
+      - run: pnpm --filter='!integration-tests' -r build
 
       - name: Publish snapshot
         id: snapshot
diff --git a/aqua-run/src/main/scala/aqua/run/FuncCompiler.scala b/aqua-run/src/main/scala/aqua/run/FuncCompiler.scala
index 134e6e46..16717549 100644
--- a/aqua-run/src/main/scala/aqua/run/FuncCompiler.scala
+++ b/aqua-run/src/main/scala/aqua/run/FuncCompiler.scala
@@ -1,34 +1,24 @@
 package aqua.run
 
-import aqua.Rendering.given
-import aqua.compiler.{AquaCompiler, AquaCompilerConf, CompileResult, CompilerAPI}
+import aqua.compiler.{AquaCompilerConf, CompileResult, CompilerAPI}
 import aqua.files.{AquaFileSources, FileModuleId}
-import aqua.{AquaIO, SpanParser}
-import aqua.io.{AquaFileError, AquaPath, PackagePath, Prelude}
+import aqua.io.{AquaFileError, AquaPath, PackagePath}
 import aqua.model.transform.TransformConfig
 import aqua.model.{AquaContext, FuncArrow}
 import aqua.parser.lift.FileSpan
-import aqua.run.CliFunc
+import aqua.{AquaIO, SpanParser}
 
-import cats.data.Validated.{invalidNec, validNec}
-import cats.data.{Chain, NonEmptyList, Validated, ValidatedNec}
-import cats.effect.IO
+import cats.data.{Chain, ValidatedNec}
 import cats.effect.kernel.{Async, Clock}
 import cats.syntax.applicative.*
+import cats.syntax.apply.*
 import cats.syntax.flatMap.*
 import cats.syntax.functor.*
-import cats.syntax.monad.*
-import cats.syntax.show.*
-import cats.syntax.traverse.*
 import cats.syntax.option.*
-import cats.syntax.either.*
-import cats.syntax.validated.*
-import cats.syntax.apply.*
+import cats.syntax.traverse.*
 import fs2.io.file.{Files, Path}
 import scribe.Logging
 
-import scala.concurrent.duration.Duration
-
 class FuncCompiler[F[_]: Files: AquaIO: Async](
   input: Option[AquaPath],
   imports: List[Path],
diff --git a/aqua-src/antithesis.aqua b/aqua-src/antithesis.aqua
index e453fa5b..04fd9406 100644
--- a/aqua-src/antithesis.aqua
+++ b/aqua-src/antithesis.aqua
@@ -1,20 +1,3 @@
-aqua StreamArgs
-
-export lng280BugWithForEmptyStreamFunc
-
-service StreamService("test-service"):
-    store(numbers: []u32, n: u32)
-
-func callService(stream: *u32, n: u32):
-    stream <<- 1
-    StreamService.store(stream, n)
-
-func returnEmptyStream() -> *u32:
-    <- *[]
-
-func lng280BugWithForEmptyStreamFunc():
-    arr = [1,2,3,4,5]
-    for a <- arr:
-      str <- returnEmptyStream()
-      -- passing the function directly won't work, see LNG-290
-      callService(str, a)
\ No newline at end of file
+func arr() -> string:
+  n = "str"
+  <- n
\ No newline at end of file
diff --git a/build.sbt b/build.sbt
index 964f26f0..cae19333 100644
--- a/build.sbt
+++ b/build.sbt
@@ -80,7 +80,7 @@ lazy val `language-server-api` = crossProject(JSPlatform, JVMPlatform)
 lazy val `language-server-apiJS` = `language-server-api`.js
   .settings(
     scalaJSLinkerConfig             ~= (_.withModuleKind(ModuleKind.CommonJSModule)),
-    scalaJSUseMainModuleInitializer := true
+    scalaJSUseMainModuleInitializer := false
   )
   .settings(addBundleJS("../../language-server-npm/aqua-lsp-api.js"))
   .enablePlugins(ScalaJSPlugin)
diff --git a/integration-tests/package.json b/integration-tests/package.json
index cbb6536c..a02ae6d3 100644
--- a/integration-tests/package.json
+++ b/integration-tests/package.json
@@ -22,7 +22,7 @@
     "pubsub": "node -r ts-node/register src/pubsub.ts",
     "exec": "npm run compile-aqua && npm run prettify-compiled && node -r ts-node/register src/index.ts",
     "run": "node -r ts-node/register src/index.ts",
-    "compile-aqua": "ts-node ./src/compile.ts",
+    "compile-aqua": "node --loader ts-node/esm ./src/compile.ts",
     "compile-aqua:air": "aqua -i ./aqua/ -o ./compiled-air -a",
     "prettify-compiled": "prettier --write src/compiled",
     "prettify": "prettier --write src",
diff --git a/language-server/language-server-api/.js/src/main/scala/aqua/lsp/AquaLSP.scala b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/AquaLSP.scala
index 0e8aa6bb..6acefc54 100644
--- a/language-server/language-server-api/.js/src/main/scala/aqua/lsp/AquaLSP.scala
+++ b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/AquaLSP.scala
@@ -1,16 +1,12 @@
 package aqua.lsp
 
 import aqua.compiler.*
-import aqua.compiler.AquaError.{ParserError as AquaParserError, *}
-import aqua.compiler.AquaWarning.*
+import aqua.compiler.AquaError.SourcesError
 import aqua.files.{AquaFileSources, AquaFilesIO, FileModuleId}
 import aqua.io.*
-import aqua.parser.lexer.{LiteralToken, Token}
+import aqua.parser.lift.FileSpan
 import aqua.parser.lift.FileSpan.F
-import aqua.parser.lift.{FileSpan, Span}
-import aqua.parser.{ArrowReturnError, BlockIndentError, LexerError, ParserError}
 import aqua.raw.ConstantRaw
-import aqua.semantics.*
 import aqua.{AquaIO, SpanParser}
 
 import cats.data.Validated
@@ -23,148 +19,12 @@ import scala.concurrent.ExecutionContext.Implicits.global
 import scala.scalajs.js
 import scala.scalajs.js.JSConverters.*
 import scala.scalajs.js.annotation.*
-import scala.scalajs.js.{UndefOr, undefined}
 import scribe.Logging
 
-@JSExportAll
-case class CompilationResult(
-  errors: js.Array[ErrorInfo],
-  warnings: js.Array[WarningInfo] = js.Array(),
-  locations: js.Array[TokenLink] = js.Array(),
-  importLocations: js.Array[TokenImport] = js.Array()
-)
-
-@JSExportAll
-case class TokenLocation(name: String, startLine: Int, startCol: Int, endLine: Int, endCol: Int)
-
-@JSExportAll
-case class TokenLink(current: TokenLocation, definition: TokenLocation)
-
-@JSExportAll
-case class TokenImport(current: TokenLocation, path: String)
-
-object TokenLocation {
-
-  def fromSpan(span: FileSpan): Option[TokenLocation] = {
-    val start = span.locationMap.value.toLineCol(span.span.startIndex)
-    val end = span.locationMap.value.toLineCol(span.span.endIndex)
-
-    for {
-      startLC <- start
-      endLC <- end
-    } yield {
-      TokenLocation(span.name, startLC._1, startLC._2, endLC._1, endLC._2)
-    }
-
-  }
-}
-
-@JSExportAll
-case class ErrorInfo(
-  start: Int,
-  end: Int,
-  message: String,
-  location: UndefOr[String]
-) {
-  // Used to distinguish from WarningInfo in TS
-  val infoType: String = "error"
-}
-
-object ErrorInfo {
-
-  def apply(fileSpan: FileSpan, message: String): ErrorInfo = {
-    val start = fileSpan.span.startIndex
-    val end = fileSpan.span.endIndex
-    ErrorInfo(start, end, message, fileSpan.name)
-  }
-
-  def applyOp(start: Int, end: Int, message: String, location: Option[String]): ErrorInfo = {
-    ErrorInfo(start, end, message, location.getOrElse(undefined))
-  }
-}
-
-@JSExportAll
-case class WarningInfo(
-  start: Int,
-  end: Int,
-  message: String,
-  location: UndefOr[String]
-) {
-  // Used to distinguish from ErrorInfo in TS
-  val infoType: String = "warning"
-}
-
-object WarningInfo {
-
-  def apply(fileSpan: FileSpan, message: String): WarningInfo = {
-    val start = fileSpan.span.startIndex
-    val end = fileSpan.span.endIndex
-    WarningInfo(start, end, message, fileSpan.name)
-  }
-}
-
 @JSExportTopLevel("AquaLSP")
-object AquaLSP extends App with Logging {
+object AquaLSP extends Logging {
 
-  private def errorToInfo(
-    error: AquaError[FileModuleId, AquaFileError, FileSpan.F]
-  ): List[ErrorInfo] = error match {
-    case AquaParserError(err) =>
-      err match {
-        case BlockIndentError(indent, message) =>
-          ErrorInfo(indent._1, message) :: Nil
-        case ArrowReturnError(point, message) =>
-          ErrorInfo(point._1, message) :: Nil
-        case LexerError((span, e)) =>
-          e.expected.toList
-            .groupBy(_.offset)
-            .map { case (offset, exps) =>
-              val localSpan = Span(offset, offset + 1)
-              val fSpan = FileSpan(span.name, span.locationMap, localSpan)
-              val errorMessages = exps.flatMap(exp => ParserError.expectationToString(exp))
-              val msg = s"${errorMessages.head}" :: errorMessages.tail.map(t => "OR " + t)
-              (offset, ErrorInfo(fSpan, msg.mkString("\n")))
-            }
-            .toList
-            .sortBy(_._1)
-            .map(_._2)
-            .reverse
-      }
-    case SourcesError(err) =>
-      ErrorInfo.applyOp(0, 0, err.showForConsole, None) :: Nil
-    case ResolveImportsError(_, token, err) =>
-      ErrorInfo(token.unit._1, err.showForConsole) :: Nil
-    case ImportError(token) =>
-      ErrorInfo(token.unit._1, "Cannot resolve import") :: Nil
-    case CycleError(modules) =>
-      ErrorInfo.applyOp(
-        0,
-        0,
-        s"Cycle loops detected in imports: ${modules.map(_.file.fileName)}",
-        None
-      ) :: Nil
-    case CompileError(err) =>
-      err match {
-        case RulesViolated(token, messages) =>
-          ErrorInfo(token.unit._1, messages.mkString("\n")) :: Nil
-        case HeaderError(token, message) =>
-          ErrorInfo(token.unit._1, message) :: Nil
-        case WrongAST(ast) =>
-          ErrorInfo.applyOp(0, 0, "Semantic error: wrong AST", None) :: Nil
-
-      }
-    case OutputError(_, err) =>
-      ErrorInfo.applyOp(0, 0, err.showForConsole, None) :: Nil
-    case AirValidationError(errors) =>
-      errors.toChain.toList.map(ErrorInfo.applyOp(0, 0, _, None))
-  }
-
-  private def warningToInfo(
-    warning: AquaWarning[FileSpan.F]
-  ): List[WarningInfo] = warning match {
-    case CompileWarning(SemanticWarning(token, messages)) =>
-      WarningInfo(token.unit._1, messages.mkString("\n")) :: Nil
-  }
+  import ResultHelper.*
 
   @JSExport
   def compile(
@@ -195,54 +55,14 @@ object AquaLSP extends App with Logging {
 
       logger.debug("Compilation done.")
 
-      def locationsToJs(
-        locations: List[(Token[FileSpan.F], Token[FileSpan.F])]
-      ): js.Array[TokenLink] = {
-        locations.flatMap { case (from, to) =>
-          val fromOp = TokenLocation.fromSpan(from.unit._1)
-          val toOp = TokenLocation.fromSpan(to.unit._1)
-
-          val link = for {
-            from <- fromOp
-            to <- toOp
-          } yield TokenLink(from, to)
-
-          if (link.isEmpty)
-            logger.warn(s"Incorrect coordinates for token '${from.unit._1.name}'")
-
-          link.toList
-        }.toJSArray
-      }
-
-      def importsToTokenImport(imports: List[LiteralToken[FileSpan.F]]): js.Array[TokenImport] =
-        imports.flatMap { lt =>
-          val (span, str) = lt.valueToken
-          val unquoted = str.substring(1, str.length - 1)
-          TokenLocation.fromSpan(span).map(l => TokenImport(l, unquoted))
-        }.toJSArray
-
-      val result = fileRes match {
+      fileRes match {
         case Valid(lsp) =>
-          val errors = lsp.errors.map(CompileError.apply).flatMap(errorToInfo)
-          val warnings = lsp.warnings.map(CompileWarning.apply).flatMap(warningToInfo)
-          errors match
-            case Nil =>
-              logger.debug("No errors on compilation.")
-            case errs =>
-              logger.debug("Errors: " + errs.mkString("\n"))
-
-          CompilationResult(
-            errors.toJSArray,
-            warnings.toJSArray,
-            locationsToJs(lsp.locations),
-            importsToTokenImport(lsp.importTokens)
-          )
+          lspToCompilationResult(lsp)
         case Invalid(e) =>
           val errors = e.toChain.toList.flatMap(errorToInfo)
           logger.debug("Errors: " + errors.mkString("\n"))
           CompilationResult(errors.toJSArray)
       }
-      result
     }
 
     proc.unsafeToFuture().toJSPromise
diff --git a/language-server/language-server-api/.js/src/main/scala/aqua/lsp/OutputTypes.scala b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/OutputTypes.scala
new file mode 100644
index 00000000..63c6ed12
--- /dev/null
+++ b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/OutputTypes.scala
@@ -0,0 +1,86 @@
+package aqua.lsp
+
+import aqua.parser.lift.FileSpan
+
+import scala.scalajs.js
+import scala.scalajs.js.annotation.JSExportAll
+import scala.scalajs.js.{UndefOr, undefined}
+
+@JSExportAll
+case class CompilationResult(
+  errors: js.Array[ErrorInfo],
+  warnings: js.Array[WarningInfo] = js.Array(),
+  locations: js.Array[TokenLink] = js.Array(),
+  importLocations: js.Array[TokenImport] = js.Array(),
+  tokens: js.Array[ExprInfoJs] = js.Array()
+)
+
+@JSExportAll
+case class ExprInfoJs(location: TokenLocation, `type`: String)
+
+@JSExportAll
+case class TokenLocation(name: String, startLine: Int, startCol: Int, endLine: Int, endCol: Int)
+
+@JSExportAll
+case class TokenLink(current: TokenLocation, definition: TokenLocation)
+
+@JSExportAll
+case class TokenImport(current: TokenLocation, path: String)
+
+object TokenLocation {
+
+  def fromSpan(span: FileSpan): Option[TokenLocation] = {
+    val start = span.locationMap.value.toLineCol(span.span.startIndex)
+    val end = span.locationMap.value.toLineCol(span.span.endIndex)
+
+    for {
+      startLC <- start
+      endLC <- end
+    } yield TokenLocation(span.name, startLC._1, startLC._2, endLC._1, endLC._2)
+
+  }
+}
+
+@JSExportAll
+case class ErrorInfo(
+  start: Int,
+  end: Int,
+  message: String,
+  location: UndefOr[String]
+) {
+  // Used to distinguish from WarningInfo in TS
+  val infoType: String = "error"
+}
+
+object ErrorInfo {
+
+  def apply(fileSpan: FileSpan, message: String): ErrorInfo = {
+    val start = fileSpan.span.startIndex
+    val end = fileSpan.span.endIndex
+    ErrorInfo(start, end, message, fileSpan.name)
+  }
+
+  def applyOp(start: Int, end: Int, message: String, location: Option[String]): ErrorInfo = {
+    ErrorInfo(start, end, message, location.getOrElse(undefined))
+  }
+}
+
+@JSExportAll
+case class WarningInfo(
+  start: Int,
+  end: Int,
+  message: String,
+  location: UndefOr[String]
+) {
+  // Used to distinguish from ErrorInfo in TS
+  val infoType: String = "warning"
+}
+
+object WarningInfo {
+
+  def apply(fileSpan: FileSpan, message: String): WarningInfo = {
+    val start = fileSpan.span.startIndex
+    val end = fileSpan.span.endIndex
+    WarningInfo(start, end, message, fileSpan.name)
+  }
+}
diff --git a/language-server/language-server-api/.js/src/main/scala/aqua/lsp/ResultHelper.scala b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/ResultHelper.scala
new file mode 100644
index 00000000..17c51b20
--- /dev/null
+++ b/language-server/language-server-api/.js/src/main/scala/aqua/lsp/ResultHelper.scala
@@ -0,0 +1,135 @@
+package aqua.lsp
+
+import aqua.compiler.AquaError.{ParserError as AquaParserError, *}
+import aqua.compiler.AquaWarning.CompileWarning
+import aqua.compiler.{AquaError, AquaWarning}
+import aqua.files.FileModuleId
+import aqua.io.AquaFileError
+import aqua.lsp.AquaLSP.logger
+import aqua.parser.lexer.LiteralToken
+import aqua.parser.lift.{FileSpan, Span}
+import aqua.parser.{ArrowReturnError, BlockIndentError, LexerError, ParserError}
+import aqua.semantics.rules.locations.{DefinitionInfo, TokenLocation as TokenLoc}
+import aqua.semantics.{HeaderError, RulesViolated, SemanticWarning, WrongAST}
+
+import cats.syntax.show.*
+import scala.scalajs.js
+import scala.scalajs.js.JSConverters.*
+import scribe.Logging
+
+object ResultHelper extends Logging {
+
+  import aqua.types.Type.given
+
+  def warningToInfo(
+    warning: AquaWarning[FileSpan.F]
+  ): List[WarningInfo] = warning match {
+    case CompileWarning(SemanticWarning(token, messages)) =>
+      WarningInfo(token.unit._1, messages.mkString("\n")) :: Nil
+  }
+
+  def errorToInfo(
+    error: AquaError[FileModuleId, AquaFileError, FileSpan.F]
+  ): List[ErrorInfo] = error match {
+    case AquaParserError(err) =>
+      err match {
+        case BlockIndentError(indent, message) =>
+          ErrorInfo(indent._1, message) :: Nil
+        case ArrowReturnError(point, message) =>
+          ErrorInfo(point._1, message) :: Nil
+        case LexerError((span, e)) =>
+          e.expected.toList
+            .groupBy(_.offset)
+            .map { case (offset, exps) =>
+              val localSpan = Span(offset, offset + 1)
+              val fSpan = FileSpan(span.name, span.locationMap, localSpan)
+              val errorMessages = exps.flatMap(exp => ParserError.expectationToString(exp))
+              val msg = s"${errorMessages.head}" :: errorMessages.tail.map(t => "OR " + t)
+              (offset, ErrorInfo(fSpan, msg.mkString("\n")))
+            }
+            .toList
+            .sortBy(_._1)
+            .map(_._2)
+            .reverse
+      }
+    case SourcesError(err) =>
+      ErrorInfo.applyOp(0, 0, err.showForConsole, None) :: Nil
+    case ResolveImportsError(_, token, err) =>
+      ErrorInfo(token.unit._1, err.showForConsole) :: Nil
+    case ImportError(token) =>
+      ErrorInfo(token.unit._1, "Cannot resolve import") :: Nil
+    case CycleError(modules) =>
+      ErrorInfo.applyOp(
+        0,
+        0,
+        s"Cycle loops detected in imports: ${modules.map(_.file.fileName)}",
+        None
+      ) :: Nil
+    case CompileError(err) =>
+      err match {
+        case RulesViolated(token, messages) =>
+          ErrorInfo(token.unit._1, messages.mkString("\n")) :: Nil
+        case HeaderError(token, message) =>
+          ErrorInfo(token.unit._1, message) :: Nil
+        case WrongAST(ast) =>
+          ErrorInfo.applyOp(0, 0, "Semantic error: wrong AST", None) :: Nil
+
+      }
+    case OutputError(_, err) =>
+      ErrorInfo.applyOp(0, 0, err.showForConsole, None) :: Nil
+    case AirValidationError(errors) =>
+      errors.toChain.toList.map(ErrorInfo.applyOp(0, 0, _, None))
+  }
+
+  private def tokensToJs(tokens: List[DefinitionInfo[FileSpan.F]]): js.Array[ExprInfoJs] =
+    tokens.flatMap { ti =>
+      TokenLocation.fromSpan(ti.token.unit._1).map { tl =>
+        val typeName = ti.`type`.show
+        ExprInfoJs(tl, typeName)
+      }
+    }.toJSArray
+
+  private def locationsToJs(
+    locations: List[TokenLoc[FileSpan.F]]
+  ): js.Array[TokenLink] =
+    locations.flatMap { case TokenLoc(from, to) =>
+      val fromOp = TokenLocation.fromSpan(from.unit._1)
+      val toOp = TokenLocation.fromSpan(to.unit._1)
+
+      val link = for {
+        from <- fromOp
+        to <- toOp
+      } yield TokenLink(from, to)
+
+      if (link.isEmpty)
+        logger.warn(s"Incorrect coordinates for token '${from.unit._1.name}'")
+
+      link.toList
+    }.toJSArray
+
+  private def importsToTokenImport(imports: List[LiteralToken[FileSpan.F]]): js.Array[TokenImport] =
+    imports.flatMap { lt =>
+      val (span, str) = lt.valueToken
+      val unquoted = str.substring(1, str.length - 1)
+      TokenLocation.fromSpan(span).map(l => TokenImport(l, unquoted))
+    }.toJSArray
+
+  def lspToCompilationResult(lsp: LspContext[FileSpan.F]): CompilationResult = {
+    val errors = lsp.errors.map(CompileError.apply).flatMap(errorToInfo)
+    val warnings = lsp.warnings.map(CompileWarning.apply).flatMap(warningToInfo)
+
+    errors match
+      case Nil =>
+        logger.debug("No errors on compilation.")
+      case errs =>
+        logger.debug("Errors: " + errs.mkString("\n"))
+
+    CompilationResult(
+      errors.toJSArray,
+      warnings.toJSArray,
+      locationsToJs(lsp.variables.flatMap(v => v.allLocations)),
+      importsToTokenImport(lsp.importTokens),
+      tokensToJs(lsp.variables.map(_.definition))
+    )
+  }
+}
diff --git a/language-server/language-server-api/src/main/scala/aqua/lsp/LSPCompiler.scala b/language-server/language-server-api/src/main/scala/aqua/lsp/LSPCompiler.scala
index f0eb0dc8..00a6659e 100644
--- a/language-server/language-server-api/src/main/scala/aqua/lsp/LSPCompiler.scala
+++ b/language-server/language-server-api/src/main/scala/aqua/lsp/LSPCompiler.scala
@@ -6,15 +6,12 @@ import aqua.raw.RawContext
 import aqua.semantics.header.{HeaderHandler, HeaderSem}
 
 import cats.data.Validated.validNec
-import cats.syntax.semigroup.*
-import cats.syntax.applicative.*
-import cats.syntax.flatMap.*
+import cats.data.{Chain, Validated, ValidatedNec}
+import cats.syntax.either.*
 import cats.syntax.functor.*
 import cats.syntax.monoid.*
-import cats.syntax.traverse.*
-import cats.syntax.either.*
+import cats.syntax.semigroup.*
 import cats.{Comonad, Monad, Monoid, Order}
-import cats.data.{Chain, NonEmptyChain, Validated, ValidatedNec}
 
 object LSPCompiler {
 
diff --git a/language-server/language-server-api/src/main/scala/aqua/lsp/LocationsInterpreter.scala b/language-server/language-server-api/src/main/scala/aqua/lsp/LocationsInterpreter.scala
index 342b202b..084d55c7 100644
--- a/language-server/language-server-api/src/main/scala/aqua/lsp/LocationsInterpreter.scala
+++ b/language-server/language-server-api/src/main/scala/aqua/lsp/LocationsInterpreter.scala
@@ -1,12 +1,10 @@
 package aqua.lsp
 
 import aqua.parser.lexer.Token
-import aqua.semantics.rules.StackInterpreter
-import aqua.semantics.rules.locations.{LocationsAlgebra, LocationsState}
-
+import aqua.semantics.rules.locations.{DefinitionInfo, LocationsAlgebra, LocationsState}
+import aqua.types.AbilityType
 import cats.data.State
 import monocle.Lens
-import monocle.macros.GenLens
 import scribe.Logging
 
 class LocationsInterpreter[S[_], X](using
@@ -15,30 +13,25 @@ class LocationsInterpreter[S[_], X](using
 
   type SX[A] = State[X, A]
 
-  val stack = new StackInterpreter[S, X, LocationsState[S], LocationsState[S]](
-    GenLens[LocationsState[S]](_.stack)
-  )
-
-  import stack.*
-
-  override def addToken(name: String, token: Token[S]): State[X, Unit] = modify { st =>
-    st.copy(tokens = st.tokens.updated(name, token))
+  override def addDefinition(definition: DefinitionInfo[S]): State[X, Unit] = modify { st =>
+    st.addDefinition(definition)
   }
 
-  private def combineFieldName(name: String, field: String): String = name + "." + field
-
-  override def addTokenWithFields(
-    name: String,
-    token: Token[S],
-    fields: List[(String, Token[S])]
-  ): State[X, Unit] = modify { st =>
-    st.copy(tokens =
-      st.tokens ++ ((name, token) +: fields.map(kv => (combineFieldName(name, kv._1), kv._2))).toMap
-    )
+  override def addDefinitionWithFields(
+    definition: DefinitionInfo[S],
+    fields: List[DefinitionInfo[S]]
+  ): State[X, Unit] = {
+    val allTokens =
+      definition +: fields.map { fieldDef =>
+        fieldDef.copy(name = AbilityType.fullName(definition.name, fieldDef.name))
+      }
+    modify { st =>
+      st.addDefinitions(allTokens)
+    }
   }
 
   def pointFieldLocation(typeName: String, fieldName: String, token: Token[S]): State[X, Unit] =
-    pointLocation(combineFieldName(typeName, fieldName), token)
+    pointLocation(AbilityType.fullName(typeName, fieldName), token)
 
   def pointTokenWithFieldLocation(
     typeName: String,
@@ -48,37 +41,21 @@ class LocationsInterpreter[S[_], X](using
   ): State[X, Unit] = {
     for {
       _ <- pointLocation(typeName, typeToken)
-      _ <- pointLocation(combineFieldName(typeName, fieldName), token)
+      _ <- pointLocation(AbilityType.fullName(typeName, fieldName), token)
     } yield {}
   }
 
   override def pointLocation(name: String, token: Token[S]): State[X, Unit] = {
     modify { st =>
-      val newLoc: Option[Token[S]] = st.stack.collectFirst {
-        case frame if frame.tokens.contains(name) => frame.tokens(name)
-      } orElse st.tokens.get(name)
-      st.copy(locations = st.locations ++ newLoc.map(token -> _).toList)
+      st.addLocation(name, token)
     }
   }
 
-  def pointLocations(locations: List[(String, Token[S])]): State[X, Unit] = {
+  def pointLocations(locations: List[(String, Token[S])]): State[X, Unit] =
     modify { st =>
-
-      val newLocs = locations.flatMap { case (name, token) =>
-        (st.stack.collectFirst {
-          case frame if frame.tokens.contains(name) => frame.tokens(name)
-        } orElse st.tokens.get(name)).map(token -> _)
-      }
-
-      st.copy(locations = st.locations ++ newLocs)
+      st.addLocations(locations)
     }
-  }
 
   private def modify(f: LocationsState[S] => LocationsState[S]): SX[Unit] =
     State.modify(lens.modify(f))
-
-  override def beginScope(): SX[Unit] =
-    stack.beginScope(LocationsState[S]())
-
-  override def endScope(): SX[Unit] = stack.endScope
 }
diff --git a/language-server/language-server-api/src/main/scala/aqua/lsp/LspContext.scala b/language-server/language-server-api/src/main/scala/aqua/lsp/LspContext.scala
index aa2ddb55..4115d103 100644
--- a/language-server/language-server-api/src/main/scala/aqua/lsp/LspContext.scala
+++ b/language-server/language-server-api/src/main/scala/aqua/lsp/LspContext.scala
@@ -2,10 +2,10 @@ package aqua.lsp
 
 import aqua.parser.lexer.{LiteralToken, NamedTypeToken, Token}
 import aqua.raw.{RawContext, RawPart}
-import aqua.semantics.{SemanticError, SemanticWarning}
 import aqua.semantics.header.Picker
-import aqua.types.{ArrowType, Type}
-
+import aqua.semantics.rules.locations.{TokenLocation, VariableInfo}
+import aqua.semantics.{SemanticError, SemanticWarning}
+import aqua.types.{AbilityType, ArrowType, Type}
 import cats.syntax.monoid.*
 import cats.{Monoid, Semigroup}
 
@@ -15,12 +15,13 @@ case class LspContext[S[_]](
   abDefinitions: Map[String, NamedTypeToken[S]] = Map.empty[String, NamedTypeToken[S]],
   rootArrows: Map[String, ArrowType] = Map.empty[String, ArrowType],
   constants: Map[String, Type] = Map.empty[String, Type],
-  tokens: Map[String, Token[S]] = Map.empty[String, Token[S]],
-  locations: List[(Token[S], Token[S])] = Nil,
+  variables: List[VariableInfo[S]] = Nil,
   importTokens: List[LiteralToken[S]] = Nil,
   errors: List[SemanticError[S]] = Nil,
   warnings: List[SemanticWarning[S]] = Nil
-)
+) {
+  lazy val allLocations: List[TokenLocation[S]] = variables.flatMap(_.allLocations)
+}
 
 object LspContext {
 
@@ -33,8 +34,8 @@ object LspContext {
         abDefinitions = x.abDefinitions ++ y.abDefinitions,
         rootArrows = x.rootArrows ++ y.rootArrows,
         constants = x.constants ++ y.constants,
-        locations = x.locations ++ y.locations,
-        tokens = x.tokens ++ y.tokens,
+        importTokens = x.importTokens ++ y.importTokens,
+        variables = x.variables ++ y.variables,
         errors = x.errors ++ y.errors,
         warnings = x.warnings ++ y.warnings
       )
@@ -87,10 +88,13 @@ object LspContext {
     override def declares(ctx: LspContext[S]): Set[String] = ctx.raw.declares
 
     override def setAbility(ctx: LspContext[S], name: String, ctxAb: LspContext[S]): LspContext[S] =
-      val prefix = name + "."
       ctx.copy(
         raw = ctx.raw.setAbility(name, ctxAb.raw),
-        tokens = ctx.tokens ++ ctxAb.tokens.map(kv => (prefix + kv._1) -> kv._2)
+        variables = ctx.variables ++ ctxAb.variables.map(v =>
+          v.copy(definition =
+            v.definition.copy(name = AbilityType.fullName(name, v.definition.name))
+          )
+        )
       )
 
     override def setModule(
@@ -113,13 +117,16 @@ object LspContext {
       declared: Boolean
     ): Option[LspContext[S]] =
       // rename tokens from one context with prefix addition
-      val newTokens = rename.map { renameStr =>
-        ctx.tokens.map {
-          case (tokenName, token) if tokenName.startsWith(name) =>
-            tokenName.replaceFirst(name, renameStr) -> token
+      val newVariables = rename.map { renameStr =>
+        ctx.variables.map {
+          case v if v.definition.name.startsWith(name) =>
+            v.copy(definition =
+              v.definition.copy(name = v.definition.name.replaceFirst(v.definition.name, renameStr))
+            )
+
           case kv => kv
         }
-      }.getOrElse(ctx.tokens)
+      }.getOrElse(ctx.variables)
 
       ctx.raw
         .pick(name, rename, declared)
@@ -132,7 +139,7 @@ object LspContext {
               ctx.rootArrows.get(name).fold(Map.empty)(t => Map(rename.getOrElse(name) -> t)),
             constants =
               ctx.constants.get(name).fold(Map.empty)(t => Map(rename.getOrElse(name) -> t)),
-            tokens = newTokens
+            variables = newVariables
           )
         )
 
diff --git a/language-server/language-server-api/src/main/scala/aqua/lsp/LspSemantics.scala b/language-server/language-server-api/src/main/scala/aqua/lsp/LspSemantics.scala
index b412e798..b8370023 100644
--- a/language-server/language-server-api/src/main/scala/aqua/lsp/LspSemantics.scala
+++ b/language-server/language-server-api/src/main/scala/aqua/lsp/LspSemantics.scala
@@ -49,7 +49,7 @@ class LspSemantics[S[_]] extends Semantics[S, LspContext[S]] {
         definitions = rawState.abilities.definitions ++ init.abDefinitions
       ),
       locations = rawState.locations.copy(
-        tokens = rawState.locations.tokens ++ init.tokens
+        variables = rawState.locations.variables ++ init.variables
       )
     )
 
@@ -69,9 +69,8 @@ class LspSemantics[S[_]] extends Semantics[S, LspContext[S]] {
           rootArrows = state.names.rootArrows,
           constants = state.names.constants,
           abDefinitions = state.abilities.definitions,
-          locations = state.locations.allLocations,
           importTokens = importTokens,
-          tokens = state.locations.tokens,
+          variables = state.locations.variables,
           errors = state.errors.toList,
           warnings = state.warnings.toList
         ).pure[Result]
diff --git a/language-server/language-server-api/src/test/scala/aqua/lsp/AquaLSPSpec.scala b/language-server/language-server-api/src/test/scala/aqua/lsp/AquaLSPSpec.scala
new file mode 100644
index 00000000..cbb0d075
--- /dev/null
+++ b/language-server/language-server-api/src/test/scala/aqua/lsp/AquaLSPSpec.scala
@@ -0,0 +1,281 @@
+package aqua.lsp
+
+import aqua.compiler.{AquaCompilerConf, AquaError, AquaSources}
+import aqua.parser.Parser
+import aqua.parser.lift.Span
+import aqua.parser.lift.Span.S
+import aqua.raw.ConstantRaw
+import aqua.semantics.rules.locations.{DefinitionInfo, TokenLocation, VariableInfo}
+import aqua.types.*
+
+import cats.Id
+import cats.data.*
+import cats.instances.string.*
+import org.scalatest.Inside
+import org.scalatest.flatspec.AnyFlatSpec
+import org.scalatest.matchers.should.Matchers
+
+class AquaLSPSpec extends AnyFlatSpec with Matchers with Inside {
+
+  private def getByPosition(code: String, str: String, position: Int): Option[(Int, Int)] = {
+    str.r.findAllMatchIn(code).toList.lift(position).map(r => (r.start, r.end))
+  }
+
+  extension (c: LspContext[Span.S]) {
+
+    def checkLocations(
+      name: String,
+      defPosition: Int,
+      usePosition: Int,
+      defCode: String,
+      useCode: Option[String] = None,
+      fieldName: Option[String] = None
+    ): Boolean = {
+      (for {
+        defPos <- getByPosition(defCode, name, defPosition)
+        usePos <- getByPosition(useCode.getOrElse(defCode), fieldName.getOrElse(name), usePosition)
+      } yield {
+        val (defStart, defEnd) = defPos
+        val (useStart, useEnd) = usePos
+        c.allLocations.exists { case TokenLocation(useT, defT) =>
+          val defSpan = defT.unit._1
+          val useSpan = useT.unit._1
+          defSpan.startIndex == defStart && defSpan.endIndex == defEnd && useSpan.startIndex == useStart && useSpan.endIndex == useEnd
+        }
+      }).getOrElse(false)
+    }
+
+    def locationsToString(): List[String] =
+      c.allLocations.map { case TokenLocation(l, r) =>
+        val lSpan = l.unit._1
+        val rSpan = r.unit._1
+        s"($l($lSpan):$r($rSpan))"
+      }
+
+    def checkTokenLoc(
+      code: String,
+      checkName: String,
+      position: Int,
+      `type`: Type,
+      // if name is combined
+      fullName: Option[String] = None,
+      printFiltered: Boolean = false
+    ): Boolean = {
+
+      getByPosition(code, checkName, position).exists { case (start, end) =>
+        val res = c.variables.exists { case VariableInfo(definition, _) =>
+          val span = definition.token.unit._1
+          definition.name == fullName.getOrElse(
+            checkName
+          ) && span.startIndex == start && span.endIndex == end && definition.`type` == `type`
+        }
+
+        if (printFiltered)
+          println(
+            c.variables
+              .map(_.definition)
+              .filter(v => v.name == fullName.getOrElse(checkName) && v.`type` == `type`)
+              .map { case DefinitionInfo(name, token, t) =>
+                val span = token.unit._1
+                s"$name(${span.startIndex}:${span.endIndex}) $t"
+              }
+          )
+
+        res
+      }
+
+    }
+  }
+
+  private def aquaSource(src: Map[String, String], imports: Map[String, String]) = {
+    new AquaSources[Id, String, String] {
+
+      override def sources: Id[ValidatedNec[String, Chain[(String, String)]]] =
+        Validated.validNec(Chain.fromSeq(src.toSeq))
+
+      override def resolveImport(from: String, imp: String): Id[ValidatedNec[String, String]] =
+        Validated.validNec(imp)
+
+      override def load(file: String): Id[ValidatedNec[String, String]] =
+        Validated.fromEither(
+          (imports ++ src)
+            .get(file)
+            .toRight(NonEmptyChain.one(s"Cannot load imported file $file"))
+        )
+    }
+  }
+
+  def compile(
+    src: Map[String, String],
+    imports: Map[String, String] = Map.empty
+  ): ValidatedNec[AquaError[String, String, S], Map[String, LspContext[S]]] = {
+    LSPCompiler
+      .compileToLsp[Id, String, String, Span.S](
+        aquaSource(src, imports),
+        id => txt => Parser.parse(Parser.parserSchema)(txt),
+        AquaCompilerConf(ConstantRaw.defaultConstants(None))
+      )
+      .leftMap { errors =>
+        println(errors)
+        errors
+      }
+  }
+
+  it should "return right tokens" in {
+    val main =
+      """module Import
+        |import foo, strFunc, num from "export2.aqua"
+        |
+        |import "../gen/OneMore.aqua"
+        |
+        |func foo_wrapper() -> string:
+        |    fooResult <- foo()
+        |    if 1 == 1:
+        |      someVar = "aaa"
+        |      strFunc(someVar)
+        |    else:
+        |      someVar = 123
+        |      num(someVar)
+        |    OneMore fooResult
+        |    OneMore.more_call()
+        |
+        |ability Ab:
+        |    someField: u32
+        |
+        |data Str:
+        |   someField: string
+        |
+        |func useAbAndStruct{Ab}():
+        |    s = Str(someField = "asd")
+        |    strFunc(s.someField)
+        |    num(Ab.someField)
+        |
+        |""".stripMargin
+    val src = Map(
+      "index.aqua" -> main
+    )
+
+    val firstImport =
+      """module Export declares strFunc, num, foo
+        |
+        |func absb() -> string:
+        |    <- "ff"
+        |
+        |func strFunc(someVar: string) -> string:
+        |    <- someVar
+        |
+        |func num(someVar: u32) -> u32:
+        |    <- someVar
+        |
+        |func foo() -> string:
+        |    <- "I am MyFooBar foo"
+        |
+        |""".stripMargin
+
+    val secondImport =
+      """
+        |service OneMore:
+        |  more_call()
+        |  consume(s: string)
+        |""".stripMargin
+
+    val imports = Map(
+      "export2.aqua" ->
+        firstImport,
+      "../gen/OneMore.aqua" ->
+        secondImport
+    )
+
+    val res = compile(src, imports).toOption.get.values.head
+
+    val serviceType = ServiceType(
+      "OneMore",
+      NonEmptyMap.of(
+        ("more_call", ArrowType(NilType, NilType)),
+        ("consume", ArrowType(ProductType.labelled(("s", ScalarType.string) :: Nil), NilType))
+      )
+    )
+
+    // inside `foo_wrapper` func
+    res.checkTokenLoc(main, "fooResult", 0, ScalarType.string) shouldBe true
+    res.checkLocations("fooResult", 0, 1, main) shouldBe true
+
+    res.checkTokenLoc(main, "someVar", 0, LiteralType.string, None, true) shouldBe true
+    res.checkLocations("someVar", 0, 1, main) shouldBe true
+    res.checkTokenLoc(main, "someVar", 2, LiteralType.unsigned) shouldBe true
+    res.checkLocations("someVar", 2, 3, main) shouldBe true
+
+    // num usage
+    res.checkLocations("num", 1, 1, firstImport, Some(main)) shouldBe true
+    // strFunc usage
+    res.checkLocations("strFunc", 1, 1, firstImport, Some(main)) shouldBe true
+    res.checkLocations("strFunc", 1, 2, firstImport, Some(main)) shouldBe true
+
+    // Str.field
+    res.checkTokenLoc(main, "someField", 1, ScalarType.string, Some("Str.someField")) shouldBe true
+    res.checkLocations("someField", 1, 3, main, None) shouldBe true
+
+    // Ab.field
+    res.checkTokenLoc(
+      main,
+      "someField",
+      0,
+      ScalarType.u32,
+      Some("Ab.someField"),
+      true
+    ) shouldBe true
+
+    // this is tokens from imports, if we will use `FileSpan.F` file names will be different
+    // OneMore service
+    res.checkTokenLoc(secondImport, "OneMore", 0, serviceType) shouldBe true
+    res.checkTokenLoc(
+      secondImport,
+      "more_call",
+      0,
+      ArrowType(NilType, NilType),
+      Some("OneMore.more_call"),
+      true
+    ) shouldBe true
+    res.checkTokenLoc(
+      secondImport,
+      "consume",
+      0,
+      ArrowType(ProductType.labelled(("s", ScalarType.string) :: Nil), NilType),
+      Some("OneMore.consume")
+    ) shouldBe true
+
+    // strFunc function and argument
+    res.checkTokenLoc(
+      firstImport,
+      "strFunc",
+      1,
+      ArrowType(
+        ProductType.labelled(("someVar", ScalarType.string) :: Nil),
+        ProductType(ScalarType.string :: Nil)
+      ),
+      None,
+      true
+    ) shouldBe true
+    res.checkTokenLoc(firstImport, "someVar", 0, ScalarType.string) shouldBe true
+
+    // num function and argument
+    res.checkTokenLoc(
+      firstImport,
+      "num",
+      1,
+      ArrowType(
+        ProductType.labelled(("someVar", ScalarType.u32) :: Nil),
+        ProductType(ScalarType.u32 :: Nil)
+      )
+    ) shouldBe true
+    res.checkTokenLoc(firstImport, "someVar", 2, ScalarType.u32, None, true) shouldBe true
+
+    // foo function
+    res.checkTokenLoc(
+      firstImport,
+      "foo",
+      1,
+      ArrowType(NilType, ProductType(ScalarType.string :: Nil))
+    ) shouldBe true
+  }
+}
diff --git a/language-server/language-server-npm/aqua-lsp-api.d.ts b/language-server/language-server-npm/aqua-lsp-api.d.ts
index c59ec827..bf705eee 100644
--- a/language-server/language-server-npm/aqua-lsp-api.d.ts
+++ b/language-server/language-server-npm/aqua-lsp-api.d.ts
@@ -6,6 +6,11 @@ export interface TokenLocation {
     endCol: number
 }
 
+export interface TokenInfo {
+    location: TokenLocation,
+    type: string
+}
+
 export interface TokenLink {
     current: TokenLocation,
     definition: TokenLocation
@@ -36,7 +41,8 @@ export interface CompilationResult {
     errors: ErrorInfo[],
     warnings: WarningInfo[],
     locations: TokenLink[],
-    importLocations: TokenImport[]
+    importLocations: TokenImport[],
+    tokens: TokenInfo[]
 }
 
 export class Compiler {
diff --git a/model/tree/src/main/scala/aqua/tree/TreeNodeCompanion.scala b/model/tree/src/main/scala/aqua/tree/TreeNodeCompanion.scala
index 241c926a..7bc42214 100644
--- a/model/tree/src/main/scala/aqua/tree/TreeNodeCompanion.scala
+++ b/model/tree/src/main/scala/aqua/tree/TreeNodeCompanion.scala
@@ -1,16 +1,14 @@
 package aqua.tree
 
+import aqua.helpers.tree.Tree
+
 import cats.Show
 import cats.data.Chain
 import cats.free.Cofree
-
-import cats.syntax.show.*
 import cats.syntax.apply.*
-
+import cats.syntax.show.*
 import scala.annotation.tailrec
 
-import aqua.helpers.Tree
-
 trait TreeNodeCompanion[T <: TreeNode[T]] {
 
   given showTreeLabel: Show[T]
diff --git a/parser/src/main/scala/aqua/parser/Ast.scala b/parser/src/main/scala/aqua/parser/Ast.scala
index e392c793..37deead0 100644
--- a/parser/src/main/scala/aqua/parser/Ast.scala
+++ b/parser/src/main/scala/aqua/parser/Ast.scala
@@ -1,10 +1,10 @@
 package aqua.parser
 
+import aqua.helpers.tree.Tree
 import aqua.parser.expr.*
 import aqua.parser.head.{HeadExpr, HeaderExpr}
 import aqua.parser.lift.{LiftParser, Span}
 import aqua.parser.lift.LiftParser.*
-import aqua.helpers.Tree
 
 import cats.data.{Chain, Validated, ValidatedNec}
 import cats.syntax.flatMap.*
diff --git a/parser/src/main/scala/aqua/parser/lexer/PropertyOp.scala b/parser/src/main/scala/aqua/parser/lexer/PropertyOp.scala
index 1e63f266..162b6158 100644
--- a/parser/src/main/scala/aqua/parser/lexer/PropertyOp.scala
+++ b/parser/src/main/scala/aqua/parser/lexer/PropertyOp.scala
@@ -61,7 +61,7 @@ case class IntoCopy[F[_]: Comonad](
 object PropertyOp {
 
   private val parseField: P[PropertyOp[Span.S]] =
-    (`.` *> anyName).lift.map(IntoField(_))
+    `.` *> anyName.lift.map(IntoField(_))
 
   val parseArrow: P[PropertyOp[Span.S]] =
     (`.` *> CallArrowToken.callBraces).map { case CallBraces(name, abilities, args) =>
diff --git a/parser/src/main/scala/aqua/parser/lexer/Token.scala b/parser/src/main/scala/aqua/parser/lexer/Token.scala
index 82f1f841..318e35bf 100644
--- a/parser/src/main/scala/aqua/parser/lexer/Token.scala
+++ b/parser/src/main/scala/aqua/parser/lexer/Token.scala
@@ -1,7 +1,5 @@
 package aqua.parser.lexer
 
-import aqua.parser.lift.Span.S
-
 import cats.data.NonEmptyList
 import cats.parse.{Accumulator0, Parser as P, Parser0 as P0}
 import cats.syntax.functor.*
diff --git a/parser/src/main/scala/aqua/parser/lift/FileSpan.scala b/parser/src/main/scala/aqua/parser/lift/FileSpan.scala
index e1a2b0c8..abd10324 100644
--- a/parser/src/main/scala/aqua/parser/lift/FileSpan.scala
+++ b/parser/src/main/scala/aqua/parser/lift/FileSpan.scala
@@ -17,6 +17,15 @@ case class FileSpan(name: String, locationMap: Eval[LocationMap], span: Span) {
    */
   def focus(ctx: Int): Option[FileSpan.Focus] =
     span.focus(locationMap.value, ctx).map(FileSpan.Focus(name, locationMap, ctx, _))
+
+  override def hashCode(): Int = (name, span).hashCode()
+  
+  override def equals(obj: Any): Boolean = {
+    obj match {
+      case FileSpan(n, _, s) => n == name && s == span
+      case _ => false
+    }
+  }
 }
 
 object FileSpan {
diff --git a/semantics/src/main/scala/aqua/semantics/Prog.scala b/semantics/src/main/scala/aqua/semantics/Prog.scala
index aadddaf4..813a000b 100644
--- a/semantics/src/main/scala/aqua/semantics/Prog.scala
+++ b/semantics/src/main/scala/aqua/semantics/Prog.scala
@@ -38,14 +38,6 @@ sealed abstract class Prog[Alg[_]: Monad, A] extends (Alg[A] => Alg[A]) {
         (_: Unit, m: A) => N.endScope() as m
       )
     )
-
-  def locationsScope[S[_]]()(implicit L: LocationsAlgebra[S, Alg]): Prog[Alg, A] =
-    wrap(
-      RunAround(
-        L.beginScope(),
-        (_: Unit, m: A) => L.endScope() as m
-      )
-    )
 }
 
 case class RunAfter[Alg[_]: Monad, A](prog: Alg[A]) extends Prog[Alg, A] {
diff --git a/semantics/src/main/scala/aqua/semantics/expr/AbilitySem.scala b/semantics/src/main/scala/aqua/semantics/expr/AbilitySem.scala
index e0798cfd..a47f8b1f 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/AbilitySem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/AbilitySem.scala
@@ -28,7 +28,7 @@ class AbilitySem[S[_]](val expr: AbilityExpr[S]) extends AnyVal {
   ): Prog[Alg, Raw] = {
     Prog.after_(
       for {
-        defs <- D.purgeDefs(expr.name)
+        defs <- D.purgeDefs()
         fields = defs.view.mapValues(d => d.name -> d.`type`).toMap
         abilityType <- T.defineAbilityType(expr.name, fields)
         result = abilityType.map(st => TypeRaw(expr.name.value, st))
diff --git a/semantics/src/main/scala/aqua/semantics/expr/DataStructSem.scala b/semantics/src/main/scala/aqua/semantics/expr/DataStructSem.scala
index 6d5cb54e..53563165 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/DataStructSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/DataStructSem.scala
@@ -22,7 +22,7 @@ class DataStructSem[S[_]](val expr: DataStructExpr[S]) extends AnyVal {
   ): Prog[Alg, Raw] =
     Prog.after((_: Raw) =>
       for {
-        defs <- D.purgeDefs(expr.name)
+        defs <- D.purgeDefs()
         fields = defs.view.mapValues(d => d.name -> d.`type`).toMap
         structType <- T.defineStructType(expr.name, fields)
         result = structType.map(st => TypeRaw(expr.name.value, st))
diff --git a/semantics/src/main/scala/aqua/semantics/expr/ServiceSem.scala b/semantics/src/main/scala/aqua/semantics/expr/ServiceSem.scala
index 0d8162ff..febb0d38 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/ServiceSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/ServiceSem.scala
@@ -45,7 +45,7 @@ class ServiceSem[S[_]](val expr: ServiceExpr[S]) extends AnyVal {
       )
     )
     serviceType <- EitherT.fromOptionF(
-      T.defineServiceType(expr.name, arrowsByName.toSortedMap.toMap),
+      T.defineServiceType(expr.name, arrowsByName.toSortedMap),
       Raw.error("Failed to define service type")
     )
     arrowsDefs = arrows.map { case (name, _) => name.value -> name }.toNem
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/ArrowSem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/ArrowSem.scala
index ac8e7771..abcaa290 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/ArrowSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/ArrowSem.scala
@@ -137,7 +137,6 @@ class ArrowSem[S[_]](val expr: ArrowExpr[S]) extends AnyVal {
     T: TypesAlgebra[S, Alg],
     N: NamesAlgebra[S, Alg],
     A: AbilitiesAlgebra[S, Alg],
-    L: LocationsAlgebra[S, Alg],
     M: ManglerAlgebra[Alg]
   ): Prog[Alg, Raw] =
     Prog
@@ -147,6 +146,4 @@ class ArrowSem[S[_]](val expr: ArrowExpr[S]) extends AnyVal {
       )
       .abilitiesScope(expr.arrowTypeExpr)
       .namesScope(expr.arrowTypeExpr)
-      .locationsScope()
-
 }
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/CatchSem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/CatchSem.scala
index 7ac8b160..9a815542 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/CatchSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/CatchSem.scala
@@ -42,6 +42,4 @@ class CatchSem[S[_]](val expr: CatchExpr[S]) extends AnyVal {
       )
       .abilitiesScope[S](expr.token)
       .namesScope(expr.token)
-      .locationsScope()
-
 }
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/DeclareStreamSem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/DeclareStreamSem.scala
index f14ae67d..d8e18ed4 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/DeclareStreamSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/DeclareStreamSem.scala
@@ -8,14 +8,9 @@ import aqua.raw.value.VarRaw
 import aqua.semantics.Prog
 import aqua.semantics.rules.names.NamesAlgebra
 import aqua.semantics.rules.types.TypesAlgebra
-import aqua.types.*
 
 import cats.Monad
-import cats.data.Chain
 import cats.data.OptionT
-import cats.syntax.applicative.*
-import cats.syntax.flatMap.*
-import cats.syntax.functor.*
 
 class DeclareStreamSem[S[_]](val expr: DeclareStreamExpr[S]) {
 
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/ElseOtherwiseSem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/ElseOtherwiseSem.scala
index 2dc27746..df98dd71 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/ElseOtherwiseSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/ElseOtherwiseSem.scala
@@ -39,5 +39,4 @@ class ElseOtherwiseSem[S[_]](val expr: ElseOtherwiseExpr[S]) extends AnyVal {
       )
       .abilitiesScope(expr.token)
       .namesScope(expr.token)
-      .locationsScope()
 }
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/IfSem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/IfSem.scala
index 43acdabe..bd25334b 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/IfSem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/IfSem.scala
@@ -56,5 +56,4 @@ class IfSem[S[_]](val expr: IfExpr[S]) extends AnyVal {
       )
       .abilitiesScope[S](expr.token)
       .namesScope[S](expr.token)
-      .locationsScope()
 }
diff --git a/semantics/src/main/scala/aqua/semantics/expr/func/TrySem.scala b/semantics/src/main/scala/aqua/semantics/expr/func/TrySem.scala
index 1b6297f7..d5b286a3 100644
--- a/semantics/src/main/scala/aqua/semantics/expr/func/TrySem.scala
+++ b/semantics/src/main/scala/aqua/semantics/expr/func/TrySem.scala
@@ -37,5 +37,4 @@ class TrySem[S[_]](val expr: TryExpr[S]) extends AnyVal {
       )
       .abilitiesScope(expr.token)
       .namesScope(expr.token)
-      .locationsScope()
 }
diff --git a/semantics/src/main/scala/aqua/semantics/rules/ValuesAlgebra.scala b/semantics/src/main/scala/aqua/semantics/rules/ValuesAlgebra.scala
index 9ec2b3aa..4ddded3d 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/ValuesAlgebra.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/ValuesAlgebra.scala
@@ -1,9 +1,7 @@
 package aqua.semantics.rules
 
-import aqua.errors.Errors.internalError
 import aqua.helpers.syntax.optiont.*
 import aqua.parser.lexer.*
-import aqua.parser.lexer.InfixToken.value
 import aqua.parser.lexer.InfixToken.{BoolOp, CmpOp, EqOp, MathOp, Op as InfOp}
 import aqua.parser.lexer.PrefixToken.Op as PrefOp
 import aqua.raw.value.*
diff --git a/semantics/src/main/scala/aqua/semantics/rules/abilities/AbilitiesInterpreter.scala b/semantics/src/main/scala/aqua/semantics/rules/abilities/AbilitiesInterpreter.scala
index 78d078b8..0f3ee8fa 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/abilities/AbilitiesInterpreter.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/abilities/AbilitiesInterpreter.scala
@@ -1,22 +1,20 @@
 package aqua.semantics.rules.abilities
 
-import aqua.parser.lexer.{Name, NamedTypeToken, Token, ValueToken}
+import aqua.parser.lexer.{Name, NamedTypeToken, Token}
+import aqua.raw.RawContext
 import aqua.raw.value.ValueRaw
-import aqua.raw.{RawContext, ServiceRaw}
 import aqua.semantics.Levenshtein
 import aqua.semantics.rules.locations.LocationsAlgebra
 import aqua.semantics.rules.mangler.ManglerAlgebra
 import aqua.semantics.rules.report.ReportAlgebra
 import aqua.semantics.rules.{StackInterpreter, abilities}
-import aqua.types.{ArrowType, ServiceType}
+import aqua.types.ArrowType
 
 import cats.data.{NonEmptyMap, State}
 import cats.syntax.applicative.*
 import cats.syntax.apply.*
-import cats.syntax.foldable.*
 import cats.syntax.functor.*
 import cats.syntax.option.*
-import cats.syntax.traverse.*
 import monocle.Lens
 import monocle.macros.GenLens
 
@@ -56,12 +54,6 @@ class AbilitiesInterpreter[S[_], X](using
       case false =>
         for {
           _ <- modify(_.defineService(name, defaultId))
-          // TODO: Is it used?
-          _ <- locations.addTokenWithFields(
-            name.value,
-            name,
-            arrowDefs.toNel.toList
-          )
         } yield true
     }
 
diff --git a/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsAlgebra.scala b/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsAlgebra.scala
index 62a336e9..c44b99ed 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsAlgebra.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsAlgebra.scala
@@ -9,7 +9,7 @@ import cats.data.{NonEmptyList, NonEmptyMap}
 trait DefinitionsAlgebra[S[_], Alg[_]] {
   def defineDef(name: Name[S], `type`: Type): Alg[Boolean]
 
-  def purgeDefs(token: NamedTypeToken[S]): Alg[Map[String, DefinitionsState.Def[S]]]
+  def purgeDefs(): Alg[Map[String, DefinitionsState.Def[S]]]
 
   def defineArrow(arrow: Name[S], `type`: ArrowType): Alg[Boolean]
 
diff --git a/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsInterpreter.scala b/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsInterpreter.scala
index 0103b598..43e75ea0 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsInterpreter.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/definitions/DefinitionsInterpreter.scala
@@ -1,28 +1,17 @@
 package aqua.semantics.rules.definitions
 
 import aqua.parser.lexer.{Name, NamedTypeToken, Token}
-import aqua.semantics.rules.StackInterpreter
 import aqua.semantics.rules.report.ReportAlgebra
-import aqua.semantics.rules.abilities.AbilitiesState
-import aqua.semantics.rules.locations.{LocationsAlgebra, LocationsState}
-import aqua.semantics.rules.types.TypesState
 import aqua.types.{ArrowType, Type}
 
-import cats.data.{NonEmptyList, NonEmptyMap, State}
-import monocle.Lens
-import monocle.macros.GenLens
-import cats.syntax.applicative.*
-import cats.syntax.apply.*
-import cats.syntax.flatMap.*
+import cats.data.{NonEmptyList, State}
 import cats.syntax.functor.*
 import cats.syntax.option.*
-
-import scala.collection.immutable.SortedMap
+import monocle.Lens
 
 class DefinitionsInterpreter[S[_], X](implicit
   lens: Lens[X, DefinitionsState[S]],
-  report: ReportAlgebra[S, State[X, *]],
-  locations: LocationsAlgebra[S, State[X, *]]
+  report: ReportAlgebra[S, State[X, *]]
 ) extends DefinitionsAlgebra[S, State[X, *]] {
   type SX[A] = State[X, A]
 
@@ -55,16 +44,9 @@ class DefinitionsInterpreter[S[_], X](implicit
   override def defineArrow(arrow: Name[S], `type`: ArrowType): SX[Boolean] =
     define(arrow, `type`, "arrow")
 
-  override def purgeDefs(
-    token: NamedTypeToken[S]
-  ): SX[Map[String, DefinitionsState.Def[S]]] =
+  override def purgeDefs(): SX[Map[String, DefinitionsState.Def[S]]] =
     getState.map(_.definitions).flatMap { defs =>
-      val names = defs.view.mapValues(_.name)
-
       for {
-        _ <- locations
-          .addTokenWithFields(token.value, token, names.toList)
-          .whenA(defs.nonEmpty)
         _ <- modify(_.copy(definitions = Map.empty))
       } yield defs
     }
diff --git a/semantics/src/main/scala/aqua/semantics/rules/locations/DummyLocationsInterpreter.scala b/semantics/src/main/scala/aqua/semantics/rules/locations/DummyLocationsInterpreter.scala
index 43a876b1..c49d72ed 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/locations/DummyLocationsInterpreter.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/locations/DummyLocationsInterpreter.scala
@@ -1,23 +1,19 @@
 package aqua.semantics.rules.locations
 
 import aqua.parser.lexer.Token
-import aqua.semantics.rules.StackInterpreter
-import aqua.semantics.rules.types.TypesState
-import monocle.Lens
-import monocle.macros.GenLens
-import cats.data.{NonEmptyList, NonEmptyMap, State}
+import cats.data.State
 
 class DummyLocationsInterpreter[S[_], X] extends LocationsAlgebra[S, State[X, *]] {
 
-  def addToken(name: String, token: Token[S]): State[X, Unit] = State.pure(())
+  def addDefinition(definition: DefinitionInfo[S]): State[X, Unit] = State.pure(())
 
-  def addTokenWithFields(
-    name: String,
-    token: Token[S],
-    fields: List[(String, Token[S])]
+  def addDefinitionWithFields(
+    definition: DefinitionInfo[S],
+    fields: List[DefinitionInfo[S]]
   ): State[X, Unit] = State.pure(())
 
-  def pointFieldLocation(typeName: String, fieldName: String, token: Token[S]): State[X, Unit] = State.pure(())
+  def pointFieldLocation(typeName: String, fieldName: String, token: Token[S]): State[X, Unit] =
+    State.pure(())
 
   def pointTokenWithFieldLocation(
     typeName: String,
diff --git a/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsAlgebra.scala b/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsAlgebra.scala
index 3a41fbdb..59b4864d 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsAlgebra.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsAlgebra.scala
@@ -1,16 +1,23 @@
 package aqua.semantics.rules.locations
+
 import aqua.parser.lexer.Token
+import aqua.types.Type
 
 trait LocationsAlgebra[S[_], Alg[_]] {
-  def addToken(name: String, token: Token[S]): Alg[Unit]
-  def addTokenWithFields(name: String, token: Token[S], fields: List[(String, Token[S])]): Alg[Unit]
+  def addDefinition(definition: DefinitionInfo[S]): Alg[Unit]
 
-  def pointTokenWithFieldLocation(typeName: String, typeToken: Token[S], fieldName: String, token: Token[S]): Alg[Unit]
+  def addDefinitionWithFields(
+    definition: DefinitionInfo[S],
+    fields: List[DefinitionInfo[S]]
+  ): Alg[Unit]
+
+  def pointTokenWithFieldLocation(
+    typeName: String,
+    typeToken: Token[S],
+    fieldName: String,
+    token: Token[S]
+  ): Alg[Unit]
   def pointFieldLocation(typeName: String, fieldName: String, token: Token[S]): Alg[Unit]
   def pointLocation(name: String, token: Token[S]): Alg[Unit]
   def pointLocations(locations: List[(String, Token[S])]): Alg[Unit]
-
-  def beginScope(): Alg[Unit]
-
-  def endScope(): Alg[Unit]
 }
diff --git a/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsState.scala b/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsState.scala
index cb0b37d0..dd11b98e 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsState.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/locations/LocationsState.scala
@@ -1,26 +1,55 @@
 package aqua.semantics.rules.locations
 
+import aqua.helpers.syntax.list.*
 import aqua.parser.lexer.Token
-import aqua.semantics.rules.types.TypesState
+
 import cats.kernel.Monoid
+import scribe.Logging
 
 case class LocationsState[S[_]](
-  tokens: Map[String, Token[S]] = Map.empty[String, Token[S]],
-  locations: List[(Token[S], Token[S])] = Nil,
-  stack: List[LocationsState[S]] = Nil
-) {
+  variables: List[VariableInfo[S]] = Nil
+) extends Logging {
 
-  lazy val allLocations: List[(Token[S], Token[S])] = locations
+  def addDefinitions(newDefinitions: List[DefinitionInfo[S]]): LocationsState[S] =
+    copy(variables = newDefinitions.map(d => VariableInfo(d)) ++ variables)
+
+  def addDefinition(newDef: DefinitionInfo[S]): LocationsState[S] =
+    copy(variables = VariableInfo(newDef) +: variables)
+
+  private def addOccurrenceToFirst(
+    vars: List[VariableInfo[S]],
+    name: String,
+    token: Token[S]
+  ): List[VariableInfo[S]] = {
+    if (!vars.exists(_.definition.name == name))
+      logger.error(s"Unexpected. Cannot add occurrence for $name")
+
+    vars.updateFirst(_.definition.name == name, v => v.copy(occurrences = token +: v.occurrences))
+  }
+
+  def addLocation(
+    name: String,
+    token: Token[S]
+  ): LocationsState[S] =
+    copy(variables = addOccurrenceToFirst(variables, name, token))
+
+  def addLocations(
+    locations: List[(String, Token[S])]
+  ): LocationsState[S] =
+    locations.foldLeft(this) { case (st, (name, token)) =>
+      st.addLocation(name, token)
+    }
 }
 
 object LocationsState {
 
-  implicit def locationsStateMonoid[S[_]]: Monoid[LocationsState[S]] = new Monoid[LocationsState[S]] {
-    override def empty: LocationsState[S] = LocationsState()
+  implicit def locationsStateMonoid[S[_]]: Monoid[LocationsState[S]] =
+    new Monoid[LocationsState[S]] {
+      override def empty: LocationsState[S] = LocationsState()
 
-    override def combine(x: LocationsState[S], y: LocationsState[S]): LocationsState[S] =
-      LocationsState(
-        tokens = x.tokens ++ y.tokens
-      )
-  }
+      override def combine(x: LocationsState[S], y: LocationsState[S]): LocationsState[S] =
+        LocationsState(
+          variables = x.variables ++ y.variables
+        )
+    }
 }
diff --git a/semantics/src/main/scala/aqua/semantics/rules/locations/VariableInfo.scala b/semantics/src/main/scala/aqua/semantics/rules/locations/VariableInfo.scala
new file mode 100644
index 00000000..efca87c0
--- /dev/null
+++ b/semantics/src/main/scala/aqua/semantics/rules/locations/VariableInfo.scala
@@ -0,0 +1,11 @@
+package aqua.semantics.rules.locations
+
+import aqua.parser.lexer.Token
+import aqua.types.Type
+
+case class DefinitionInfo[S[_]](name: String, token: Token[S], `type`: Type)
+case class TokenLocation[S[_]](usage: Token[S], definition: Token[S])
+
+case class VariableInfo[S[_]](definition: DefinitionInfo[S], occurrences: List[Token[S]] = Nil) {
+  def allLocations: List[TokenLocation[S]] = occurrences.map(o => TokenLocation(o, definition.token))
+}
diff --git a/semantics/src/main/scala/aqua/semantics/rules/names/NamesInterpreter.scala b/semantics/src/main/scala/aqua/semantics/rules/names/NamesInterpreter.scala
index e3357eab..d47cd85e 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/names/NamesInterpreter.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/names/NamesInterpreter.scala
@@ -4,15 +4,12 @@ import aqua.errors.Errors.internalError
 import aqua.parser.lexer.{Name, Token}
 import aqua.semantics.Levenshtein
 import aqua.semantics.rules.StackInterpreter
-import aqua.semantics.rules.locations.LocationsAlgebra
+import aqua.semantics.rules.locations.{DefinitionInfo, LocationsAlgebra}
 import aqua.semantics.rules.report.ReportAlgebra
 import aqua.types.{ArrowType, StreamType, Type}
 
 import cats.data.{OptionT, State}
 import cats.syntax.all.*
-import cats.syntax.applicative.*
-import cats.syntax.flatMap.*
-import cats.syntax.functor.*
 import monocle.Lens
 import monocle.macros.GenLens
 
@@ -117,13 +114,13 @@ class NamesInterpreter[S[_], X](using
       case None =>
         mapStackHeadM(report.error(name, "Cannot define a variable in the root scope").as(false))(
           fr => (fr.addName(name, `type`) -> true).pure
-        ) <* locations.addToken(name.value, name)
+        ) <* locations.addDefinition(DefinitionInfo(name.value, name, `type`))
     }
 
   override def derive(name: Name[S], `type`: Type, derivedFrom: Set[String]): State[X, Boolean] =
     define(name, `type`).flatTap(defined =>
       mapStackHead_(_.derived(name, derivedFrom)).whenA(defined)
-    ) <* locations.addToken(name.value, name)
+    )
 
   override def getDerivedFrom(fromNames: List[Set[String]]): State[X, List[Set[String]]] =
     mapStackHead(Nil)(frame =>
@@ -142,7 +139,7 @@ class NamesInterpreter[S[_], X](using
             constants = st.constants.updated(name.value, `type`)
           )
         ).as(true)
-    }.flatTap(_ => locations.addToken(name.value, name))
+    }.flatTap(_ => locations.addDefinition(DefinitionInfo(name.value, name, `type`)))
 
   override def defineArrow(name: Name[S], arrowType: ArrowType, isRoot: Boolean): SX[Boolean] =
     readName(name.value).flatMap {
@@ -166,8 +163,10 @@ class NamesInterpreter[S[_], X](using
             report
               .error(name, "Cannot define a variable in the root scope")
               .as(false)
-        )(fr => (fr.addArrow(name, arrowType) -> true).pure)
-    }.flatTap(_ => locations.addToken(name.value, name))
+        )(fr => (fr.addArrow(name, arrowType) -> true).pure).flatTap(_ =>
+          locations.addDefinition(DefinitionInfo[S](name.value, name, arrowType))
+        )
+    }
 
   override def streamsDefinedWithinScope(): SX[Map[String, StreamType]] =
     mapStackHead(Map.empty) { frame =>
diff --git a/semantics/src/main/scala/aqua/semantics/rules/types/TypesInterpreter.scala b/semantics/src/main/scala/aqua/semantics/rules/types/TypesInterpreter.scala
index 7df3cddd..4f76de4d 100644
--- a/semantics/src/main/scala/aqua/semantics/rules/types/TypesInterpreter.scala
+++ b/semantics/src/main/scala/aqua/semantics/rules/types/TypesInterpreter.scala
@@ -3,14 +3,14 @@ package aqua.semantics.rules.types
 import aqua.parser.lexer.*
 import aqua.raw.value.*
 import aqua.semantics.rules.StackInterpreter
-import aqua.semantics.rules.locations.LocationsAlgebra
+import aqua.semantics.rules.locations.{DefinitionInfo, LocationsAlgebra}
 import aqua.semantics.rules.report.ReportAlgebra
 import aqua.semantics.rules.types.TypeResolution.TypeResolutionError
 import aqua.types.*
 import aqua.types.Type.*
 
+import cats.data.*
 import cats.data.Validated.{Invalid, Valid}
-import cats.data.{Chain, NonEmptyList, NonEmptyMap, OptionT, State}
 import cats.syntax.applicative.*
 import cats.syntax.apply.*
 import cats.syntax.flatMap.*
@@ -97,7 +97,8 @@ class TypesInterpreter[S[_], X](using
           nonEmptyFields =>
             val `type` = AbilityType(name.value, nonEmptyFields)
 
-            modify(_.defineType(name, `type`)).as(`type`.some)
+            locateNamedType(name, `type`, fields) >> modify(_.defineType(name, `type`))
+              .as(`type`.some)
         )
     }
 
@@ -131,10 +132,20 @@ class TypesInterpreter[S[_], X](using
       ).semiflatMap(nonEmptyArrows =>
         val `type` = ServiceType(name.value, nonEmptyArrows)
 
-        modify(_.defineType(name, `type`)).as(`type`)
+        locateNamedType(name, `type`, fields) >> modify(_.defineType(name, `type`)).as(`type`)
       ).value
     )
 
+  private def locateNamedType(
+    name: NamedTypeToken[S],
+    t: NamedType,
+    fields: Map[String, (Name[S], Type)]
+  ) =
+    locations.addDefinitionWithFields(
+      DefinitionInfo[S](name.value, name, t),
+      fields.map { case (n, (t, ty)) => DefinitionInfo[S](n, t, ty) }.toList
+    )
+
   override def defineStructType(
     name: NamedTypeToken[S],
     fields: Map[String, (Name[S], Type)]
@@ -159,7 +170,8 @@ class TypesInterpreter[S[_], X](using
             )(nonEmptyFields =>
               val `type` = StructType(name.value, nonEmptyFields)
 
-              modify(_.defineType(name, `type`)).as(`type`.some)
+              locateNamedType(name, `type`, fields) >> modify(_.defineType(name, `type`))
+                .as(`type`.some)
             )
         )
     )
@@ -170,7 +182,7 @@ class TypesInterpreter[S[_], X](using
       case Some(_) => report.error(name, s"Type `${name.value}` was already defined").as(false)
       case None =>
         modify(_.defineType(name, target))
-          .productL(locations.addToken(name.value, name))
+          .productL(locations.addDefinition(DefinitionInfo(name.value, name.asName, target)))
           .as(true)
     }
 
diff --git a/types/src/main/scala/aqua/types/Type.scala b/types/src/main/scala/aqua/types/Type.scala
index e5f6bf7e..1ddd8058 100644
--- a/types/src/main/scala/aqua/types/Type.scala
+++ b/types/src/main/scala/aqua/types/Type.scala
@@ -4,15 +4,15 @@ import aqua.errors.Errors.internalError
 import aqua.types.*
 import aqua.types.Type.*
 
-import cats.data.NonEmptyList
 import cats.data.NonEmptyMap
 import cats.syntax.applicative.*
 import cats.syntax.foldable.*
 import cats.syntax.functor.*
 import cats.syntax.option.*
 import cats.syntax.partialOrder.*
+import cats.syntax.show.*
 import cats.syntax.traverse.*
-import cats.{Eval, Foldable, Functor, PartialOrder, Traverse}
+import cats.{Eval, Foldable, Functor, PartialOrder, Show, Traverse}
 import scala.collection.immutable.SortedMap
 
 sealed trait Type {
@@ -282,7 +282,8 @@ object CollectionType {
       .map[Type] {
         case StreamType(el) => ArrayType(el)
         case dt: DataType => dt
-      }.reduceLeftOption(_ `∩` _)
+      }
+      .reduceLeftOption(_ `∩` _)
       .map {
         // In case we mix values of uncomparable types, intersection returns bottom, meaning "uninhabited type".
         // But we want to get to TopType instead: this would mean that intersection is empty, and you cannot
@@ -516,4 +517,48 @@ object Type {
 
   given PartialOrder[Type] =
     CompareTypes.partialOrder
+
+  given Show[DataType] = {
+    case LiteralType.signed =>
+      "i32"
+    case LiteralType.unsigned =>
+      "u32"
+    case LiteralType.number =>
+      "u32"
+    case LiteralType.float =>
+      "f32"
+    case LiteralType.string =>
+      "string"
+    case LiteralType.bool =>
+      "bool"
+    case t =>
+      t.toString
+  }
+
+  // pretty print for Type
+  given Show[Type] = {
+    case ArrayType(el) =>
+      s"[]${el.show}"
+    case OptionType(el) =>
+      s"?${el.show}"
+    case StreamType(el) =>
+      s"*${el.show}"
+    case ArrowType(domain, codomain) =>
+      val domainStr = domain match {
+        case _: LabeledConsType =>
+          domain.toLabelledList().map { case (s, t) => s"$s: ${t.show}" }.mkString("(", ", ", ")")
+        case _ => domain.toList.mkString("(", ", ", ")")
+      }
+      val codomainStr = codomain.toList match {
+        case Nil => ""
+        case l => " -> " + l.mkString(", ")
+      }
+      domainStr + codomainStr
+    case nt: NamedType =>
+      s"${nt.fullName}(${nt.fields.map(_.show).toNel.toList.map(kv => kv._1 + ": " + kv._2).mkString(", ")})"
+    case t: DataType =>
+      t.show
+    case t =>
+      t.toString
+  }
 }
diff --git a/utils/helpers/src/main/scala/aqua/helpers/syntax/list.scala b/utils/helpers/src/main/scala/aqua/helpers/syntax/list.scala
new file mode 100644
index 00000000..b5dce107
--- /dev/null
+++ b/utils/helpers/src/main/scala/aqua/helpers/syntax/list.scala
@@ -0,0 +1,19 @@
+package aqua.helpers.syntax
+
+import scala.annotation.tailrec
+
+object list {
+  extension[A] (l: List[A]) {
+    def updateFirst[B >: A](p: A => Boolean, f: A => B): List[B] = {
+      @tailrec
+      def update(left: List[B], right: List[A]): List[B] =
+        right match {
+          case a :: tail if p(a) => left.reverse ::: f(a) :: tail
+          case a :: tail => update(a :: left, tail)
+          case Nil => left.reverse
+        }
+
+      update(Nil, l)
+    }
+  }
+}
diff --git a/utils/helpers/src/main/scala/aqua/syntax/optiont.scala b/utils/helpers/src/main/scala/aqua/helpers/syntax/optiont.scala
similarity index 100%
rename from utils/helpers/src/main/scala/aqua/syntax/optiont.scala
rename to utils/helpers/src/main/scala/aqua/helpers/syntax/optiont.scala
diff --git a/utils/helpers/src/main/scala/aqua/tree/Tree.scala b/utils/helpers/src/main/scala/aqua/helpers/tree/Tree.scala
similarity index 79%
rename from utils/helpers/src/main/scala/aqua/tree/Tree.scala
rename to utils/helpers/src/main/scala/aqua/helpers/tree/Tree.scala
index b958e14b..3ed2c68c 100644
--- a/utils/helpers/src/main/scala/aqua/tree/Tree.scala
+++ b/utils/helpers/src/main/scala/aqua/helpers/tree/Tree.scala
@@ -1,13 +1,9 @@
-package aqua.helpers
+package aqua.helpers.tree
 
-import cats.data.Chain
 import cats.free.Cofree
-import cats.Traverse
-import cats.Show
-import cats.Eval
-import cats.syntax.show.*
-import cats.syntax.traverse.*
 import cats.syntax.foldable.*
+import cats.syntax.show.*
+import cats.{Eval, Show, Traverse}
 
 object Tree {