diff --git a/build.sbt b/build.sbt
index 61842c40c..0975b7d88 100644
--- a/build.sbt
+++ b/build.sbt
@@ -396,7 +396,7 @@ lazy val mainProj = (project in file("main"))
   .settings(
     testedBaseSettings,
     name := "Main",
-    libraryDependencies ++= scalaXml.value ++ Seq(launcherInterface) ++ log4jDependencies,
+    libraryDependencies ++= scalaXml.value ++ Seq(launcherInterface) ++ log4jDependencies ++ Seq(scalaCacheCaffeine),
     managedSourceDirectories in Compile +=
       baseDirectory.value / "src" / "main" / "contraband-scala",
     sourceManaged in (Compile, generateContrabands) := baseDirectory.value / "src" / "main" / "contraband-scala",
diff --git a/main/src/main/scala/sbt/Defaults.scala b/main/src/main/scala/sbt/Defaults.scala
index 7041fe6de..d40467dff 100755
--- a/main/src/main/scala/sbt/Defaults.scala
+++ b/main/src/main/scala/sbt/Defaults.scala
@@ -26,7 +26,7 @@ import sbt.internal.librarymanagement.mavenint.{
   PomExtraDependencyAttributes,
   SbtPomExtraProperties
 }
-import sbt.internal.server.LanguageServerReporter
+import sbt.internal.server.{ LanguageServerReporter, Definition }
 import sbt.internal.testing.TestLogger
 import sbt.internal.util._
 import sbt.internal.util.Attributed.data
@@ -498,6 +498,7 @@ object Defaults extends BuildCommon {
     },
     compileIncSetup := compileIncSetupTask.value,
     console := consoleTask.value,
+    collectAnalyses := Definition.collectAnalysesTask.value,
     consoleQuick := consoleQuickTask.value,
     discoveredMainClasses := (compile map discoverMainClasses storeAs discoveredMainClasses xtriggeredBy compile).value,
     discoveredSbtPlugins := discoverSbtPluginNames.value,
diff --git a/main/src/main/scala/sbt/Keys.scala b/main/src/main/scala/sbt/Keys.scala
index 211b46b1b..3df25679d 100644
--- a/main/src/main/scala/sbt/Keys.scala
+++ b/main/src/main/scala/sbt/Keys.scala
@@ -449,6 +449,9 @@ object Keys {
   val interactionService = taskKey[InteractionService]("Service used to ask for user input through the current user interface(s).").withRank(CTask)
   val insideCI = SettingKey[Boolean]("insideCI", "Determines if the SBT is running in a Continuous Integration environment", AMinusSetting)
 
+  // sbt server internal
+  val collectAnalyses = taskKey[Unit]("Collect analysis file locations for later use.")
+
   // special
   val sessionVars = AttributeKey[SessionVar.Map]("sessionVars", "Bindings that exist for the duration of the session.", Invisible)
   val parallelExecution = settingKey[Boolean]("Enables (true) or disables (false) parallel execution of tasks.").withRank(BMinusSetting)
diff --git a/main/src/main/scala/sbt/Main.scala b/main/src/main/scala/sbt/Main.scala
index 61fe64cd0..09d668c4b 100644
--- a/main/src/main/scala/sbt/Main.scala
+++ b/main/src/main/scala/sbt/Main.scala
@@ -101,6 +101,9 @@ final class ConsoleMain extends xsbti.AppMain {
 
 object StandardMain {
   private[sbt] lazy val exchange = new CommandExchange()
+  import scalacache._
+  import scalacache.caffeine._
+  private[sbt] val cache: Cache[Any] = CaffeineCache[Any]
 
   def runManaged(s: State): xsbti.MainResult = {
     val previous = TrapExit.installManager()
@@ -132,6 +135,9 @@ object StandardMain {
       Exec(x, None)
     }
     val initAttrs = BuiltinCommands.initialAttributes
+    import scalacache.modes.scalaFuture._
+    import scala.concurrent.ExecutionContext.Implicits.global
+    cache.removeAll()
     val s = State(
       configuration,
       initialDefinitions,
@@ -157,7 +163,7 @@ import TemplateCommandUtil.templateCommand
 
 object BuiltinCommands {
   def initialAttributes = AttributeMap.empty
-
+  import BasicCommands.exit
   def ConsoleCommands: Seq[Command] =
     Seq(ignore, exit, IvyConsole.command, setLogLevel, early, act, nop)
 
diff --git a/main/src/main/scala/sbt/internal/server/Definition.scala b/main/src/main/scala/sbt/internal/server/Definition.scala
new file mode 100644
index 000000000..4459861db
--- /dev/null
+++ b/main/src/main/scala/sbt/internal/server/Definition.scala
@@ -0,0 +1,329 @@
+/*
+ * sbt
+ * Copyright 2011 - 2017, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under BSD-3-Clause license (see LICENSE)
+ */
+
+package sbt
+package internal
+package server
+
+import sbt.internal.inc.MixedAnalyzingCompiler
+import sbt.internal.langserver.ErrorCodes
+import sbt.util.Logger
+import scala.annotation.tailrec
+import scala.concurrent.{ ExecutionContext, Future }
+import scala.concurrent.duration.Duration.Inf
+import scala.util.matching.Regex.MatchIterator
+import java.nio.file.{ Files, Paths }
+import sbt.StandardMain
+
+private[sbt] object Definition {
+  import java.net.URI
+  import Keys._
+  import sbt.internal.inc.Analysis
+  import sbt.internal.inc.JavaInterfaceUtil._
+  val AnalysesKey = "lsp.definition.analyses.key"
+
+  import sjsonnew.JsonFormat
+  def send[A: JsonFormat](source: CommandSource, execId: String)(params: A): Unit = {
+    for {
+      channel <- StandardMain.exchange.channels.collectFirst {
+        case c if c.name == source.channelName => c
+      }
+    } yield {
+      channel.publishEvent(params, Option(execId))
+    }
+  }
+
+  object textProcessor {
+    private val isIdentifier = {
+      import scala.tools.reflect.{ ToolBox, ToolBoxError }
+      lazy val tb =
+        scala.reflect.runtime.universe
+          .runtimeMirror(this.getClass.getClassLoader)
+          .mkToolBox()
+      import tb._
+      lazy val check = parse _ andThen compile _
+      (identifier: String) =>
+        try {
+          check(s"val $identifier = 0; val ${identifier}${identifier} = $identifier")
+          true
+        } catch {
+          case _: ToolBoxError => false
+        }
+    }
+
+    private def findInBackticks(line: String, point: Int): Option[String] = {
+      val (even, odd) = line.zipWithIndex
+        .collect {
+          case (char, backtickIndex) if char == '`' =>
+            backtickIndex
+        }
+        .zipWithIndex
+        .partition { bs =>
+          val (_, index) = bs
+          index % 2 == 0
+        }
+      even
+        .collect {
+          case (backtickIndex, _) => backtickIndex
+        }
+        .zip {
+          odd.collect {
+            case (backtickIndex, _) => backtickIndex + 1
+          }
+        }
+        .collectFirst {
+          case (from, to) if from <= point && point < to => line.slice(from, to)
+        }
+    }
+
+    def identifier(line: String, point: Int): Option[String] = findInBackticks(line, point).orElse {
+      val whiteSpaceReg = "(\\s|\\.)+".r
+      val (zero, end) = fold(Seq.empty)(whiteSpaceReg.findAllIn(line))
+        .collect {
+          case (white, ind) => (ind, ind + white.length)
+        }
+        .fold((0, line.length)) { (z, e) =>
+          val (from, to) = e
+          val (left, right) = z
+          (if (to > left && to <= point) to else left,
+           if (from < right && from >= point) from else right)
+        }
+      val ranges = for {
+        from <- zero to point
+        to <- point to end
+      } yield (from -> to)
+      ranges
+        .sortBy {
+          case (from, to) => -(to - from)
+        }
+        .foldLeft(Seq.empty[String]) { (z, e) =>
+          val (from, to) = e
+          val fragment = line.slice(from, to).trim
+          z match {
+            case Nil if fragment.nonEmpty && isIdentifier(fragment) => fragment +: z
+            case h +: _ if h.length < fragment.length && isIdentifier(fragment) =>
+              Seq(fragment)
+            case h +: _ if h.length == fragment.length && isIdentifier(fragment) =>
+              fragment +: z
+            case z => z
+          }
+        }
+        .headOption
+    }
+
+    private def asClassObjectIdentifier(sym: String) =
+      Seq(s".$sym", s".$sym$$", s"$$$sym", s"$$$sym$$")
+    def potentialClsOrTraitOrObj(sym: String): PartialFunction[String, String] = {
+      import scala.reflect.NameTransformer
+      val encodedSym = NameTransformer.encode(sym.toSeq match {
+        case '`' +: body :+ '`' => body.mkString
+        case noBackticked       => noBackticked.mkString
+      })
+      val action: PartialFunction[String, String] = {
+        case potentialClassOrTraitOrObject
+            if asClassObjectIdentifier(encodedSym).exists(potentialClassOrTraitOrObject.endsWith) ||
+              encodedSym == potentialClassOrTraitOrObject ||
+              s"$encodedSym$$" == potentialClassOrTraitOrObject =>
+          potentialClassOrTraitOrObject
+      }
+      action
+    }
+
+    @tailrec
+    private def fold(z: Seq[(String, Int)])(it: MatchIterator): Seq[(String, Int)] = {
+      if (!it.hasNext) z
+      else fold(z :+ (it.next() -> it.start))(it)
+    }
+
+    def classTraitObjectInLine(sym: String)(line: String): Seq[(String, Int)] = {
+      import scala.util.matching.Regex.quote
+      val potentials =
+        Seq(s"object\\s+${quote(sym)}".r,
+            s"trait\\s+${quote(sym)} *\\[?".r,
+            s"class\\s+${quote(sym)} *\\[?".r)
+      potentials
+        .flatMap { reg =>
+          fold(Seq.empty)(reg.findAllIn(line))
+        }
+        .collect {
+          case (name, pos) =>
+            (if (name.endsWith("[")) name.init.trim else name.trim) -> pos
+        }
+    }
+
+    import java.io.File
+    def markPosition(file: File, sym: String): Seq[(File, Long, Long, Long)] = {
+      import java.nio.file._
+      import scala.collection.JavaConverters._
+      val findInLine = classTraitObjectInLine(sym)(_)
+      Files
+        .lines(file.toPath)
+        .iterator
+        .asScala
+        .zipWithIndex
+        .flatMap {
+          case (line, lineNumber) =>
+            findInLine(line)
+              .collect {
+                case (sym, from) =>
+                  (file, lineNumber.toLong, from.toLong, from.toLong + sym.length)
+              }
+        }
+        .toSeq
+        .distinct
+    }
+  }
+
+  import sbt.internal.langserver.TextDocumentPositionParams
+  import sjsonnew.shaded.scalajson.ast.unsafe.JValue
+  private def getDefinition(jsonDefinition: JValue): Option[TextDocumentPositionParams] = {
+    import sbt.internal.langserver.codec.JsonProtocol._
+    import sjsonnew.support.scalajson.unsafe.Converter
+    Converter.fromJson[TextDocumentPositionParams](jsonDefinition).toOption
+  }
+
+  import java.io.File
+  private def storeAnalysis(cacheFile: File, useBinary: Boolean): Option[Analysis] =
+    MixedAnalyzingCompiler
+      .staticCachedStore(cacheFile, !useBinary)
+      .get
+      .toOption
+      .collect {
+        case contents =>
+          contents.getAnalysis
+      }
+      .collect {
+        case a: Analysis => a
+      }
+
+  import scalacache._
+  private[sbt] def updateCache[F[_]](cache: Cache[Any])(cacheFile: String, useBinary: Boolean)(
+      implicit
+      mode: Mode[F],
+      flags: Flags): F[Any] = {
+    mode.M.flatMap(cache.get(AnalysesKey)) {
+      case None =>
+        cache.put(AnalysesKey)(Set(cacheFile -> useBinary -> None), Option(Inf))
+      case Some(set) =>
+        cache.put(AnalysesKey)(
+          set.asInstanceOf[Set[((String, Boolean), Option[Analysis])]].filterNot {
+            case ((file, _), _) => file == cacheFile
+          } + (cacheFile -> useBinary -> None),
+          Option(Inf))
+      case _ => mode.M.pure(())
+    }
+  }
+
+  def collectAnalysesTask = Def.task {
+    val cacheFile = compileIncSetup.value.cacheFile.getAbsolutePath
+    val useBinary = enableBinaryCompileAnalysis.value
+    val s = state.value
+    s.log.debug(s"analysis location ${(cacheFile -> useBinary)}")
+    import scalacache.modes.sync._
+    updateCache(StandardMain.cache)(cacheFile, useBinary)
+  }
+
+  private[sbt] def getAnalyses(log: Logger): Future[Seq[Analysis]] = {
+    import scalacache.modes.scalaFuture._
+    import scala.concurrent.ExecutionContext.Implicits.global
+    StandardMain.cache
+      .get(AnalysesKey)
+      .collect {
+        case Some(a) => a.asInstanceOf[Set[((String, Boolean), Option[Analysis])]]
+      }
+      .map { caches =>
+        val (working, uninitialized) = caches.partition { cacheAnalysis =>
+          cacheAnalysis._2 != None
+        }
+        val addToCache = uninitialized.collect {
+          case (title @ (file, useBinary), _) if Files.exists(Paths.get(file)) =>
+            (title, storeAnalysis(Paths.get(file).toFile, !useBinary))
+        }
+        val validCaches = working ++ addToCache
+        if (addToCache.nonEmpty)
+          StandardMain.cache.put(AnalysesKey)(validCaches, Option(Inf))
+        validCaches.toSeq.collect {
+          case (_, Some(analysis)) =>
+            analysis
+        }
+      }
+  }
+
+  def lspDefinition(jsonDefinition: JValue,
+                    requestId: String,
+                    commandSource: CommandSource,
+                    log: Logger)(implicit ec: ExecutionContext): Future[Unit] = Future {
+    val LspDefinitionLogHead = "lsp-definition"
+    import sjsonnew.support.scalajson.unsafe.CompactPrinter
+    log.debug(s"$LspDefinitionLogHead json request: ${CompactPrinter(jsonDefinition)}")
+    lazy val analyses = getAnalyses(log)
+    val definition = getDefinition(jsonDefinition)
+    definition
+      .flatMap { definition =>
+        val uri = URI.create(definition.textDocument.uri)
+        import java.nio.file._
+        Files
+          .lines(Paths.get(uri))
+          .skip(definition.position.line)
+          .findFirst
+          .toOption
+          .flatMap { line =>
+            log.debug(s"$LspDefinitionLogHead found line: $line")
+            textProcessor
+              .identifier(line, definition.position.character.toInt)
+          }
+      }
+      .map { sym =>
+        log.debug(s"symbol $sym")
+        analyses
+          .map { analyses =>
+            val locations = analyses.par.flatMap { analysis =>
+              val selectPotentials = textProcessor.potentialClsOrTraitOrObj(sym)
+              val classes =
+                (analysis.apis.allInternalClasses ++ analysis.apis.allExternals).collect {
+                  selectPotentials
+                }
+              log.debug(s"$LspDefinitionLogHead potentials: $classes")
+              classes
+                .flatMap { className =>
+                  analysis.relations.definesClass(className) ++ analysis.relations
+                    .libraryDefinesClass(className)
+                }
+                .flatMap { classFile =>
+                  textProcessor.markPosition(classFile, sym).collect {
+                    case (file, line, from, to) =>
+                      import sbt.internal.langserver.{ Location, Position, Range }
+                      Location(file.toURI.toURL.toString,
+                               Range(Position(line, from), Position(line, to)))
+                  }
+                }
+            }.seq
+            log.debug(s"$LspDefinitionLogHead locations ${locations}")
+            import sbt.internal.langserver.codec.JsonProtocol._
+            send(commandSource, requestId)(locations.toArray)
+          }
+          .recover {
+            case anyException @ _ =>
+              log.warn(
+                s"Problem with processing analyses $anyException for ${CompactPrinter(jsonDefinition)}")
+              import sbt.internal.protocol.JsonRpcResponseError
+              import sbt.internal.protocol.codec.JsonRPCProtocol._
+              send(commandSource, requestId)(
+                JsonRpcResponseError(ErrorCodes.InternalError,
+                                     "Problem with processing analyses.",
+                                     None))
+          }
+      }
+      .orElse {
+        log.info(s"Symbol not found in definition request ${CompactPrinter(jsonDefinition)}")
+        import sbt.internal.langserver.Location
+        import sbt.internal.langserver.codec.JsonProtocol._
+        send(commandSource, requestId)(Array.empty[Location])
+        None
+      }
+  }
+}
diff --git a/main/src/main/scala/sbt/internal/server/LanguageServerProtocol.scala b/main/src/main/scala/sbt/internal/server/LanguageServerProtocol.scala
index 776078ae6..5c18b926b 100644
--- a/main/src/main/scala/sbt/internal/server/LanguageServerProtocol.scala
+++ b/main/src/main/scala/sbt/internal/server/LanguageServerProtocol.scala
@@ -35,10 +35,8 @@ private[sbt] trait LanguageServerProtocol extends CommandChannel {
   protected def onSettingQuery(execId: Option[String], req: Q): Unit
 
   protected def onRequestMessage(request: JsonRpcRequestMessage): Unit = {
-
     import sbt.internal.langserver.codec.JsonProtocol._
     import internalJsonProtocol._
-
     def json =
       request.params.getOrElse(
         throw LangServerError(ErrorCodes.InvalidParams,
@@ -57,9 +55,13 @@ private[sbt] trait LanguageServerProtocol extends CommandChannel {
           else throw LangServerError(ErrorCodes.InvalidRequest, "invalid token")
         } else ()
         setInitialized(true)
+        append(Exec(s"collectAnalyses", Some(request.id), Some(CommandSource(name))))
         langRespond(InitializeResult(serverCapabilities), Option(request.id))
       case "textDocument/didSave" =>
-        append(Exec("compile", Some(request.id), Some(CommandSource(name))))
+        append(Exec(";compile; collectAnalyses", Some(request.id), Some(CommandSource(name))))
+      case "textDocument/definition" =>
+        import scala.concurrent.ExecutionContext.Implicits.global
+        Definition.lspDefinition(json, request.id, CommandSource(name), log)
       case "sbt/exec" =>
         val param = Converter.fromJson[SbtExecParams](json).get
         append(Exec(param.commandLine, Some(request.id), Some(CommandSource(name))))
@@ -68,7 +70,7 @@ private[sbt] trait LanguageServerProtocol extends CommandChannel {
         val param = Converter.fromJson[Q](json).get
         onSettingQuery(Option(request.id), param)
       }
-      case _ => ()
+      case unhandledRequest => log.debug(s"Unhandled request received: $unhandledRequest")
     }
   }
 
@@ -149,6 +151,7 @@ private[sbt] trait LanguageServerProtocol extends CommandChannel {
   private[sbt] lazy val serverCapabilities: ServerCapabilities = {
     ServerCapabilities(textDocumentSync =
                          TextDocumentSyncOptions(true, 0, false, false, SaveOptions(false)),
-                       hoverProvider = false)
+                       hoverProvider = false,
+                       definitionProvider = true)
   }
 }
diff --git a/main/src/test/scala/sbt/internal/server/DefinitionTest.scala b/main/src/test/scala/sbt/internal/server/DefinitionTest.scala
new file mode 100644
index 000000000..534d77083
--- /dev/null
+++ b/main/src/test/scala/sbt/internal/server/DefinitionTest.scala
@@ -0,0 +1,177 @@
+/*
+ * sbt
+ * Copyright 2011 - 2017, Lightbend, Inc.
+ * Copyright 2008 - 2010, Mark Harrah
+ * Licensed under BSD-3-Clause license (see LICENSE)
+ */
+
+package sbt
+package internal
+package server
+
+import sbt.internal.inc.Analysis
+
+class DefinitionTest extends org.specs2.mutable.Specification {
+  import Definition.textProcessor
+
+  "text processor" should {
+    "find valid standard scala identifier when caret is set at the start of it" in {
+      textProcessor.identifier("val identifier = 0", 4) must beSome("identifier")
+    }
+    "not find valid standard scala identifier because it is '='" in {
+      textProcessor.identifier("val identifier = 0", 15) must beNone
+    }
+    "find valid standard scala identifier when caret is set in the middle of it" in {
+      textProcessor.identifier("val identifier = 0", 11) must beSome("identifier")
+    }
+    "find valid standard scala identifier with comma" in {
+      textProcessor.identifier("def foo(a: identifier, b: other) = ???", 13) must beSome(
+        "identifier")
+    }
+    "find valid standard short scala identifier when caret is set at the start of it" in {
+      textProcessor.identifier("val a = 0", 4) must beSome("a")
+    }
+    "find valid standard short scala identifier when caret is set at the end of it" in {
+      textProcessor.identifier("def foo(f: Int) = Foo(f)", 19) must beSome("Foo")
+    }
+    "find valid non-standard short scala identifier when caret is set at the start of it" in {
+      textProcessor.identifier("val == = 0", 4) must beSome("==")
+    }
+    "find valid non-standard short scala identifier when caret is set in the middle of it" in {
+      textProcessor.identifier("val == = 0", 5) must beSome("==")
+    }
+    "find valid non-standard short scala identifier when caret is set at the end of it" in {
+      textProcessor.identifier("val == = 0", 6) must beSome("==")
+    }
+    "choose longest valid standard scala identifier from scala keyword when caret is set at the start of it" in {
+      textProcessor.identifier("val k = 0", 0) must beSome("va") or beSome("al")
+    }
+    "choose longest valid standard scala identifier from scala keyword when caret is set in the middle of it" in {
+      textProcessor.identifier("val k = 0", 1) must beSome("va") or beSome("al")
+    }
+    "match symbol as class name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("com.acme.A") must be_==("com.acme.A")
+    }
+    "match symbol as object name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("com.acme.A$") must be_==("com.acme.A$")
+    }
+    "match symbol as inner class name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("com.acme.A$A") must be_==("com.acme.A$A")
+    }
+    "match symbol as inner object name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("com.acme.A$A$") must be_==("com.acme.A$A$")
+    }
+    "match symbol as default package class name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("A") must be_==("A")
+    }
+    "match symbol as default package object name" in {
+      textProcessor.potentialClsOrTraitOrObj("A")("A$") must be_==("A$")
+    }
+    "match object in line version 1" in {
+      textProcessor.classTraitObjectInLine("A")("   object A  ") must contain(("object A", 3))
+    }
+    "match object in line version 2" in {
+      textProcessor.classTraitObjectInLine("A")("   object    A  ") must contain(("object    A", 3))
+    }
+    "match object in line version 3" in {
+      textProcessor.classTraitObjectInLine("A")("object A {") must contain(("object A", 0))
+    }
+    "not match object in line" in {
+      textProcessor.classTraitObjectInLine("B")("object A  ") must be empty
+    }
+    "match class in line version 1" in {
+      textProcessor.classTraitObjectInLine("A")("   class A  ") must contain(("class A", 3))
+    }
+    "match class in line version 2" in {
+      textProcessor.classTraitObjectInLine("A")("   class    A  ") must contain(("class    A", 3))
+    }
+    "match class in line version 3" in {
+      textProcessor.classTraitObjectInLine("A")("class A {") must contain(("class A", 0))
+    }
+    "match class in line version 4" in {
+      textProcessor.classTraitObjectInLine("A")("   class    A[A]  ") must contain(
+        ("class    A", 3))
+    }
+    "match class in line version 5" in {
+      textProcessor.classTraitObjectInLine("A")("   class    A  [A] ") must contain(
+        ("class    A", 3))
+    }
+    "match class in line version 6" in {
+      textProcessor.classTraitObjectInLine("A")("class A[A[_]] {") must contain(("class A", 0))
+    }
+    "not match class in line" in {
+      textProcessor.classTraitObjectInLine("B")("class A  ") must be empty
+    }
+    "match trait in line version 1" in {
+      textProcessor.classTraitObjectInLine("A")("   trait A  ") must contain(("trait A", 3))
+    }
+    "match trait in line version 2" in {
+      textProcessor.classTraitObjectInLine("A")("   trait    A  ") must contain(("trait    A", 3))
+    }
+    "match trait in line version 3" in {
+      textProcessor.classTraitObjectInLine("A")("trait A {") must contain(("trait A", 0))
+    }
+    "match trait in line version 4" in {
+      textProcessor.classTraitObjectInLine("A")("   trait    A[A]  ") must contain(
+        ("trait    A", 3))
+    }
+    "match trait in line version 5" in {
+      textProcessor.classTraitObjectInLine("A")("   trait    A  [A] ") must contain(
+        ("trait    A", 3))
+    }
+    "match trait in line version 6" in {
+      textProcessor.classTraitObjectInLine("A")("trait A[A[_]] {") must contain(("trait A", 0))
+    }
+    "not match trait in line" in {
+      textProcessor.classTraitObjectInLine("B")("trait A  ") must be empty
+    }
+  }
+  "definition" should {
+    import scalacache.caffeine._
+    import scalacache.modes.sync._
+    "cache data in cache" in {
+      val cache = CaffeineCache[Any]
+      val cacheFile = "Test.scala"
+      val useBinary = true
+
+      Definition.updateCache(cache)(cacheFile, useBinary)
+
+      val actual = cache.get(Definition.AnalysesKey)
+
+      actual.collect {
+        case s => s.asInstanceOf[Set[((String, Boolean), Option[Analysis])]]
+      }.get should contain("Test.scala" -> true -> None)
+    }
+    "replace cache data in cache" in {
+      val cache = CaffeineCache[Any]
+      val cacheFile = "Test.scala"
+      val useBinary = true
+      val falseUseBinary = false
+
+      Definition.updateCache(cache)(cacheFile, falseUseBinary)
+      Definition.updateCache(cache)(cacheFile, useBinary)
+
+      val actual = cache.get(Definition.AnalysesKey)
+
+      actual.collect {
+        case s => s.asInstanceOf[Set[((String, Boolean), Option[Analysis])]]
+      }.get should contain("Test.scala" -> true -> None)
+    }
+    "cache more data in cache" in {
+      val cache = CaffeineCache[Any]
+      val cacheFile = "Test.scala"
+      val useBinary = true
+      val otherCacheFile = "OtherTest.scala"
+      val otherUseBinary = false
+
+      Definition.updateCache(cache)(otherCacheFile, otherUseBinary)
+      Definition.updateCache(cache)(cacheFile, useBinary)
+
+      val actual = cache.get(Definition.AnalysesKey)
+
+      actual.collect {
+        case s => s.asInstanceOf[Set[((String, Boolean), Option[Analysis])]]
+      }.get should contain("Test.scala" -> true -> None, "OtherTest.scala" -> false -> None)
+    }
+  }
+}
diff --git a/project/Dependencies.scala b/project/Dependencies.scala
index c9f430e17..9a0339a1e 100644
--- a/project/Dependencies.scala
+++ b/project/Dependencies.scala
@@ -125,4 +125,6 @@ object Dependencies {
   val log4jSlf4jImpl = "org.apache.logging.log4j" % "log4j-slf4j-impl" % log4jVersion
   // specify all of log4j modules to prevent misalignment
   val log4jDependencies = Vector(log4jApi, log4jCore, log4jSlf4jImpl)
+
+  val scalaCacheCaffeine = "com.github.cb372" %% "scalacache-caffeine" % "0.20.0"
 }
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/ServerCapabilities.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/ServerCapabilities.scala
index c40b895e5..802428214 100644
--- a/protocol/src/main/contraband-scala/sbt/internal/langserver/ServerCapabilities.scala
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/ServerCapabilities.scala
@@ -7,22 +7,24 @@ package sbt.internal.langserver
 final class ServerCapabilities private (
   val textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions],
   /** The server provides hover support. */
-  val hoverProvider: Option[Boolean]) extends Serializable {
+  val hoverProvider: Option[Boolean],
+  /** Goto definition */
+  val definitionProvider: Option[Boolean]) extends Serializable {
   
   
   
   override def equals(o: Any): Boolean = o match {
-    case x: ServerCapabilities => (this.textDocumentSync == x.textDocumentSync) && (this.hoverProvider == x.hoverProvider)
+    case x: ServerCapabilities => (this.textDocumentSync == x.textDocumentSync) && (this.hoverProvider == x.hoverProvider) && (this.definitionProvider == x.definitionProvider)
     case _ => false
   }
   override def hashCode: Int = {
-    37 * (37 * (37 * (17 + "sbt.internal.langserver.ServerCapabilities".##) + textDocumentSync.##) + hoverProvider.##)
+    37 * (37 * (37 * (37 * (17 + "sbt.internal.langserver.ServerCapabilities".##) + textDocumentSync.##) + hoverProvider.##) + definitionProvider.##)
   }
   override def toString: String = {
-    "ServerCapabilities(" + textDocumentSync + ", " + hoverProvider + ")"
+    "ServerCapabilities(" + textDocumentSync + ", " + hoverProvider + ", " + definitionProvider + ")"
   }
-  protected[this] def copy(textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions] = textDocumentSync, hoverProvider: Option[Boolean] = hoverProvider): ServerCapabilities = {
-    new ServerCapabilities(textDocumentSync, hoverProvider)
+  protected[this] def copy(textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions] = textDocumentSync, hoverProvider: Option[Boolean] = hoverProvider, definitionProvider: Option[Boolean] = definitionProvider): ServerCapabilities = {
+    new ServerCapabilities(textDocumentSync, hoverProvider, definitionProvider)
   }
   def withTextDocumentSync(textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions]): ServerCapabilities = {
     copy(textDocumentSync = textDocumentSync)
@@ -36,9 +38,15 @@ final class ServerCapabilities private (
   def withHoverProvider(hoverProvider: Boolean): ServerCapabilities = {
     copy(hoverProvider = Option(hoverProvider))
   }
+  def withDefinitionProvider(definitionProvider: Option[Boolean]): ServerCapabilities = {
+    copy(definitionProvider = definitionProvider)
+  }
+  def withDefinitionProvider(definitionProvider: Boolean): ServerCapabilities = {
+    copy(definitionProvider = Option(definitionProvider))
+  }
 }
 object ServerCapabilities {
   
-  def apply(textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions], hoverProvider: Option[Boolean]): ServerCapabilities = new ServerCapabilities(textDocumentSync, hoverProvider)
-  def apply(textDocumentSync: sbt.internal.langserver.TextDocumentSyncOptions, hoverProvider: Boolean): ServerCapabilities = new ServerCapabilities(Option(textDocumentSync), Option(hoverProvider))
+  def apply(textDocumentSync: Option[sbt.internal.langserver.TextDocumentSyncOptions], hoverProvider: Option[Boolean], definitionProvider: Option[Boolean]): ServerCapabilities = new ServerCapabilities(textDocumentSync, hoverProvider, definitionProvider)
+  def apply(textDocumentSync: sbt.internal.langserver.TextDocumentSyncOptions, hoverProvider: Boolean, definitionProvider: Boolean): ServerCapabilities = new ServerCapabilities(Option(textDocumentSync), Option(hoverProvider), Option(definitionProvider))
 }
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentIdentifier.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentIdentifier.scala
new file mode 100644
index 000000000..bb29b3d7f
--- /dev/null
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentIdentifier.scala
@@ -0,0 +1,34 @@
+/**
+ * This code is generated using [[http://www.scala-sbt.org/contraband/ sbt-contraband]].
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.langserver
+/** Text documents are identified using a URI. On the protocol level, URIs are passed as strings. */
+final class TextDocumentIdentifier private (
+  /** The text document's URI. */
+  val uri: String) extends Serializable {
+  
+  
+  
+  override def equals(o: Any): Boolean = o match {
+    case x: TextDocumentIdentifier => (this.uri == x.uri)
+    case _ => false
+  }
+  override def hashCode: Int = {
+    37 * (37 * (17 + "sbt.internal.langserver.TextDocumentIdentifier".##) + uri.##)
+  }
+  override def toString: String = {
+    "TextDocumentIdentifier(" + uri + ")"
+  }
+  protected[this] def copy(uri: String = uri): TextDocumentIdentifier = {
+    new TextDocumentIdentifier(uri)
+  }
+  def withUri(uri: String): TextDocumentIdentifier = {
+    copy(uri = uri)
+  }
+}
+object TextDocumentIdentifier {
+  
+  def apply(uri: String): TextDocumentIdentifier = new TextDocumentIdentifier(uri)
+}
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentPositionParams.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentPositionParams.scala
new file mode 100644
index 000000000..5d7d3edd8
--- /dev/null
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/TextDocumentPositionParams.scala
@@ -0,0 +1,39 @@
+/**
+ * This code is generated using [[http://www.scala-sbt.org/contraband/ sbt-contraband]].
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.langserver
+/** Goto definition params model */
+final class TextDocumentPositionParams private (
+  /** The text document. */
+  val textDocument: sbt.internal.langserver.TextDocumentIdentifier,
+  /** The position inside the text document. */
+  val position: sbt.internal.langserver.Position) extends Serializable {
+  
+  
+  
+  override def equals(o: Any): Boolean = o match {
+    case x: TextDocumentPositionParams => (this.textDocument == x.textDocument) && (this.position == x.position)
+    case _ => false
+  }
+  override def hashCode: Int = {
+    37 * (37 * (37 * (17 + "sbt.internal.langserver.TextDocumentPositionParams".##) + textDocument.##) + position.##)
+  }
+  override def toString: String = {
+    "TextDocumentPositionParams(" + textDocument + ", " + position + ")"
+  }
+  protected[this] def copy(textDocument: sbt.internal.langserver.TextDocumentIdentifier = textDocument, position: sbt.internal.langserver.Position = position): TextDocumentPositionParams = {
+    new TextDocumentPositionParams(textDocument, position)
+  }
+  def withTextDocument(textDocument: sbt.internal.langserver.TextDocumentIdentifier): TextDocumentPositionParams = {
+    copy(textDocument = textDocument)
+  }
+  def withPosition(position: sbt.internal.langserver.Position): TextDocumentPositionParams = {
+    copy(position = position)
+  }
+}
+object TextDocumentPositionParams {
+  
+  def apply(textDocument: sbt.internal.langserver.TextDocumentIdentifier, position: sbt.internal.langserver.Position): TextDocumentPositionParams = new TextDocumentPositionParams(textDocument, position)
+}
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/JsonProtocol.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/JsonProtocol.scala
index f946496ec..7898d1d72 100644
--- a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/JsonProtocol.scala
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/JsonProtocol.scala
@@ -19,4 +19,6 @@ trait JsonProtocol extends sjsonnew.BasicJsonProtocol
   with sbt.internal.langserver.codec.LogMessageParamsFormats
   with sbt.internal.langserver.codec.PublishDiagnosticsParamsFormats
   with sbt.internal.langserver.codec.SbtExecParamsFormats
+  with sbt.internal.langserver.codec.TextDocumentIdentifierFormats
+  with sbt.internal.langserver.codec.TextDocumentPositionParamsFormats
 object JsonProtocol extends JsonProtocol
\ No newline at end of file
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/ServerCapabilitiesFormats.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/ServerCapabilitiesFormats.scala
index 4bac79256..028865f7f 100644
--- a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/ServerCapabilitiesFormats.scala
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/ServerCapabilitiesFormats.scala
@@ -13,8 +13,9 @@ implicit lazy val ServerCapabilitiesFormat: JsonFormat[sbt.internal.langserver.S
       unbuilder.beginObject(js)
       val textDocumentSync = unbuilder.readField[Option[sbt.internal.langserver.TextDocumentSyncOptions]]("textDocumentSync")
       val hoverProvider = unbuilder.readField[Option[Boolean]]("hoverProvider")
+      val definitionProvider = unbuilder.readField[Option[Boolean]]("definitionProvider")
       unbuilder.endObject()
-      sbt.internal.langserver.ServerCapabilities(textDocumentSync, hoverProvider)
+      sbt.internal.langserver.ServerCapabilities(textDocumentSync, hoverProvider, definitionProvider)
       case None =>
       deserializationError("Expected JsObject but found None")
     }
@@ -23,6 +24,7 @@ implicit lazy val ServerCapabilitiesFormat: JsonFormat[sbt.internal.langserver.S
     builder.beginObject()
     builder.addField("textDocumentSync", obj.textDocumentSync)
     builder.addField("hoverProvider", obj.hoverProvider)
+    builder.addField("definitionProvider", obj.definitionProvider)
     builder.endObject()
   }
 }
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentIdentifierFormats.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentIdentifierFormats.scala
new file mode 100644
index 000000000..fd093e0cf
--- /dev/null
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentIdentifierFormats.scala
@@ -0,0 +1,27 @@
+/**
+ * This code is generated using [[http://www.scala-sbt.org/contraband/ sbt-contraband]].
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.langserver.codec
+import _root_.sjsonnew.{ Unbuilder, Builder, JsonFormat, deserializationError }
+trait TextDocumentIdentifierFormats { self: sjsonnew.BasicJsonProtocol =>
+implicit lazy val TextDocumentIdentifierFormat: JsonFormat[sbt.internal.langserver.TextDocumentIdentifier] = new JsonFormat[sbt.internal.langserver.TextDocumentIdentifier] {
+  override def read[J](jsOpt: Option[J], unbuilder: Unbuilder[J]): sbt.internal.langserver.TextDocumentIdentifier = {
+    jsOpt match {
+      case Some(js) =>
+      unbuilder.beginObject(js)
+      val uri = unbuilder.readField[String]("uri")
+      unbuilder.endObject()
+      sbt.internal.langserver.TextDocumentIdentifier(uri)
+      case None =>
+      deserializationError("Expected JsObject but found None")
+    }
+  }
+  override def write[J](obj: sbt.internal.langserver.TextDocumentIdentifier, builder: Builder[J]): Unit = {
+    builder.beginObject()
+    builder.addField("uri", obj.uri)
+    builder.endObject()
+  }
+}
+}
diff --git a/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentPositionParamsFormats.scala b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentPositionParamsFormats.scala
new file mode 100644
index 000000000..87f231e91
--- /dev/null
+++ b/protocol/src/main/contraband-scala/sbt/internal/langserver/codec/TextDocumentPositionParamsFormats.scala
@@ -0,0 +1,29 @@
+/**
+ * This code is generated using [[http://www.scala-sbt.org/contraband/ sbt-contraband]].
+ */
+
+// DO NOT EDIT MANUALLY
+package sbt.internal.langserver.codec
+import _root_.sjsonnew.{ Unbuilder, Builder, JsonFormat, deserializationError }
+trait TextDocumentPositionParamsFormats { self: sbt.internal.langserver.codec.TextDocumentIdentifierFormats with sbt.internal.langserver.codec.PositionFormats with sjsonnew.BasicJsonProtocol =>
+implicit lazy val TextDocumentPositionParamsFormat: JsonFormat[sbt.internal.langserver.TextDocumentPositionParams] = new JsonFormat[sbt.internal.langserver.TextDocumentPositionParams] {
+  override def read[J](jsOpt: Option[J], unbuilder: Unbuilder[J]): sbt.internal.langserver.TextDocumentPositionParams = {
+    jsOpt match {
+      case Some(js) =>
+      unbuilder.beginObject(js)
+      val textDocument = unbuilder.readField[sbt.internal.langserver.TextDocumentIdentifier]("textDocument")
+      val position = unbuilder.readField[sbt.internal.langserver.Position]("position")
+      unbuilder.endObject()
+      sbt.internal.langserver.TextDocumentPositionParams(textDocument, position)
+      case None =>
+      deserializationError("Expected JsObject but found None")
+    }
+  }
+  override def write[J](obj: sbt.internal.langserver.TextDocumentPositionParams, builder: Builder[J]): Unit = {
+    builder.beginObject()
+    builder.addField("textDocument", obj.textDocument)
+    builder.addField("position", obj.position)
+    builder.endObject()
+  }
+}
+}
diff --git a/protocol/src/main/contraband/lsp.contra b/protocol/src/main/contraband/lsp.contra
index 18bd0a42c..a46d27d1d 100644
--- a/protocol/src/main/contraband/lsp.contra
+++ b/protocol/src/main/contraband/lsp.contra
@@ -83,6 +83,9 @@ type ServerCapabilities {
 
   ## The server provides hover support.
   hoverProvider: Boolean
+
+  ## Goto definition
+  definitionProvider: Boolean
 }
 
 type TextDocumentSyncOptions {
@@ -127,3 +130,18 @@ type PublishDiagnosticsParams {
 type SbtExecParams {
   commandLine: String!
 }
+
+## Goto definition params model
+type TextDocumentPositionParams {
+	## The text document.
+	textDocument: sbt.internal.langserver.TextDocumentIdentifier!
+
+	## The position inside the text document.
+	position: sbt.internal.langserver.Position!
+}
+
+## Text documents are identified using a URI. On the protocol level, URIs are passed as strings.
+type TextDocumentIdentifier {
+	## The text document's URI.
+	uri: String!
+}