diff --git a/build.sbt b/build.sbt
index 2c6fa48c881..5665c14add7 100644
--- a/build.sbt
+++ b/build.sbt
@@ -172,6 +172,11 @@ lazy val interfaces = project
     )
   )
 
+val genyVersion = Def.setting {
+  if (scalaVersion.value.startsWith("2.11")) "0.1.6"
+  else "0.1.8"
+}
+
 lazy val mtags = project
   .settings(
     moduleName := "mtags",
@@ -189,6 +194,7 @@ lazy val mtags = project
       "com.thoughtworks.qdox" % "qdox" % "2.0-M9", // for java mtags
       "org.jsoup" % "jsoup" % "1.11.3", // for extracting HTML from javadocs
       "org.lz4" % "lz4-java" % "1.6.0", // for streaming hashing when indexing classpaths
+      "com.lihaoyi" %% "geny" % genyVersion.value,
       "org.scalameta" % "semanticdb-scalac-core" % V.scalameta cross CrossVersion.full
     ),
     libraryDependencies ++= {
diff --git a/metals/src/main/scala/scala/meta/internal/builds/BuildTools.scala b/metals/src/main/scala/scala/meta/internal/builds/BuildTools.scala
index 3eaf8df20ed..4b71e7ed3f4 100644
--- a/metals/src/main/scala/scala/meta/internal/builds/BuildTools.scala
+++ b/metals/src/main/scala/scala/meta/internal/builds/BuildTools.scala
@@ -2,8 +2,8 @@ package scala.meta.internal.builds
 
 import java.nio.file.Files
 import java.util.Properties
-import scala.meta.internal.jdk.CollectionConverters._
 import scala.meta.io.AbsolutePath
+import scala.meta.internal.metals.MetalsEnrichments._
 
 /**
  * Detects what build tool is used in this workspace.
@@ -31,18 +31,7 @@ final class BuildTools(
     bspGlobalDirectories.exists(hasJsonFile)
   }
   private def hasJsonFile(dir: AbsolutePath): Boolean = {
-    dir.isDirectory && {
-      val ls = Files.list(dir.toNIO)
-      val hasJsonFile =
-        try {
-          ls.iterator()
-            .asScala
-            .exists(_.getFileName.toString.endsWith(".json"))
-        } finally {
-          ls.close()
-        }
-      hasJsonFile
-    }
+    dir.list.exists(_.extension == "json")
   }
   // Returns true if there's a build.sbt file or project/build.properties with sbt.version
   def isSbt: Boolean = {
diff --git a/metals/src/main/scala/scala/meta/internal/builds/Digest.scala b/metals/src/main/scala/scala/meta/internal/builds/Digest.scala
index b52d3c7ca8e..542733b78e3 100644
--- a/metals/src/main/scala/scala/meta/internal/builds/Digest.scala
+++ b/metals/src/main/scala/scala/meta/internal/builds/Digest.scala
@@ -11,7 +11,6 @@ import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.io.AbsolutePath
 import scala.util.control.NonFatal
 import scala.xml.Node
-import scala.meta.internal.mtags.ListFiles
 
 case class Digest(
     md5: String,
@@ -61,11 +60,9 @@ object Digest {
   ): Boolean = {
     if (!path.isDirectory) true
     else {
-      var success = true
-      ListFiles.foreach(path) { file =>
-        success &= digestFile(file, digest)
+      path.list.forall { file =>
+        digestFile(file, digest)
       }
-      success
     }
   }
 
@@ -122,7 +119,7 @@ object Digest {
       chldrenSuccessful.forall(p => p)
     }
     try {
-      val xml = XML.loadFile(file.toNIO.toFile())
+      val xml = XML.loadFile(file.toNIO.toFile)
       digestElement(xml)
       xml.text.split("\\s+").foreach(word => digest.update(word.getBytes))
       true
diff --git a/metals/src/main/scala/scala/meta/internal/builds/GradleDigest.scala b/metals/src/main/scala/scala/meta/internal/builds/GradleDigest.scala
index 061c0e7434a..142703d5e6f 100644
--- a/metals/src/main/scala/scala/meta/internal/builds/GradleDigest.scala
+++ b/metals/src/main/scala/scala/meta/internal/builds/GradleDigest.scala
@@ -1,9 +1,8 @@
 package scala.meta.internal.builds
 
-import scala.meta.io.AbsolutePath
-import scala.meta.internal.mtags.WalkFiles
 import java.security.MessageDigest
-import scala.meta.internal.mtags.ListFiles
+import scala.meta.internal.metals.MetalsEnrichments._
+import scala.meta.io.AbsolutePath
 
 object GradleDigest extends Digestable {
   override protected def digestWorkspace(
@@ -23,33 +22,28 @@ object GradleDigest extends Digestable {
   }
 
   def digestBuildSrc(path: AbsolutePath, digest: MessageDigest): Boolean = {
-    WalkFiles.foreach(path) { file =>
+    path.listRecursive.forall { file =>
       Digest.digestFile(file, digest)
     }
-    true
   }
 
   def digestSubProjects(
       workspace: AbsolutePath,
       digest: MessageDigest
   ): Boolean = {
-    val directories = ListFiles(workspace).filter(_.isDirectory)
+    val directories = workspace.list.filter(_.isDirectory).toList
 
     val (subprojects, dirs) = directories.partition { file =>
-      ListFiles
-        .exists(file) { path =>
-          val stringPath = path.toString
-          stringPath.endsWith(".gradle") || stringPath.endsWith("gradle.kts")
-        }
+      file.list.exists { path =>
+        val stringPath = path.toString
+        stringPath.endsWith(".gradle") || stringPath.endsWith("gradle.kts")
+      }
     }
     /*
        If a dir contains a gradle file we need to treat is as a workspace
      */
     val isSuccessful = subprojects.forall { file =>
-      digestWorkspace(
-        file,
-        digest
-      )
+      digestWorkspace(file, digest)
     }
 
     /*
diff --git a/metals/src/main/scala/scala/meta/internal/builds/MavenDigest.scala b/metals/src/main/scala/scala/meta/internal/builds/MavenDigest.scala
index 3ab08ceb635..a9154892533 100644
--- a/metals/src/main/scala/scala/meta/internal/builds/MavenDigest.scala
+++ b/metals/src/main/scala/scala/meta/internal/builds/MavenDigest.scala
@@ -2,20 +2,18 @@ package scala.meta.internal.builds
 
 import java.security.MessageDigest
 import scala.meta.io.AbsolutePath
-import scala.meta.internal.mtags.WalkFiles
-import scala.meta.internal.mtags.MtagsEnrichments._
+import scala.meta.internal.metals.MetalsEnrichments._
 
 object MavenDigest extends Digestable {
   override protected def digestWorkspace(
       workspace: AbsolutePath,
       digest: MessageDigest
   ): Boolean = {
-    Digest.digestFile(workspace.resolve("pom.xml"), digest)
-    WalkFiles.foreach(workspace) { file =>
-      if (file.filename == "pom.xml") {
+    workspace.listRecursive.forall {
+      case file if file.filename == "pom.xml" =>
         Digest.digestFile(file, digest)
-      }
+      case _ =>
+        true
     }
-    true
   }
 }
diff --git a/metals/src/main/scala/scala/meta/internal/builds/SbtDigest.scala b/metals/src/main/scala/scala/meta/internal/builds/SbtDigest.scala
index 67fb8c36656..783e94ff35d 100644
--- a/metals/src/main/scala/scala/meta/internal/builds/SbtDigest.scala
+++ b/metals/src/main/scala/scala/meta/internal/builds/SbtDigest.scala
@@ -5,7 +5,6 @@ import java.security.MessageDigest
 import scala.meta.internal.builds.Digest.digestScala
 import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.io.AbsolutePath
-import scala.meta.internal.mtags.ListFiles
 
 object SbtDigest extends Digestable {
 
@@ -20,14 +19,11 @@ object SbtDigest extends Digestable {
     Digest.digestDirectory(project.resolve("project"), digest)
   }
 
-  def digestSbtFiles(
-      path: AbsolutePath,
-      digest: MessageDigest
-  ): Boolean = {
-    if (!path.isDirectory) {
-      true
+  def digestSbtFiles(path: AbsolutePath, digest: MessageDigest): Boolean = {
+    if (path.isDirectory) {
+      path.list.forall(file => digestSbtFile(digest)(file))
     } else {
-      ListFiles.forall(path)(file => digestSbtFile(digest)(file))
+      true
     }
   }
 
diff --git a/metals/src/main/scala/scala/meta/internal/metals/BloopServers.scala b/metals/src/main/scala/scala/meta/internal/metals/BloopServers.scala
index 4e0d0467532..f3de80ff823 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/BloopServers.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/BloopServers.scala
@@ -55,8 +55,10 @@ final class BloopServers(
       maxRetries: Int = defaultRetries
   ): Future[Option[BuildServerConnection]] = {
     newServerUnsafe().map(Option(_)).recoverWith {
-      case NonFatal(_) if maxRetries > 0 =>
-        scribe.warn(s"BSP retry ${defaultRetries - maxRetries + 1}")
+      case NonFatal(e) if maxRetries > 0 =>
+        val retry = defaultRetries - maxRetries + 1
+        val cause = e.getMessage
+        scribe.warn(s"BSP retry $retry due to: $cause", e)
         newServer(maxRetries - 1)
     }
   }
diff --git a/metals/src/main/scala/scala/meta/internal/metals/BspServers.scala b/metals/src/main/scala/scala/meta/internal/metals/BspServers.scala
index e23a723c67d..8039bac42e2 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/BspServers.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/BspServers.scala
@@ -14,7 +14,6 @@ import scala.meta.internal.metals.MetalsEnrichments._
 import scala.meta.internal.mtags.MD5
 import scala.meta.io.AbsolutePath
 import scala.util.Try
-import scala.meta.internal.mtags.ListFiles
 
 /**
  * Implements BSP server discovery, named "BSP Connection Protocol" in the spec.
@@ -124,11 +123,9 @@ final class BspServers(
   private def findJsonFiles(): List[AbsolutePath] = {
     val buf = List.newBuilder[AbsolutePath]
     def visit(dir: AbsolutePath): Unit =
-      if (dir.isDirectory) {
-        ListFiles.foreach(dir) { p =>
-          if (p.extension == "json") {
-            buf += p
-          }
+      dir.list.foreach { p =>
+        if (p.extension == "json") {
+          buf += p
         }
       }
     visit(workspace.resolve(".bsp"))
diff --git a/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala b/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
index b157fe36f9b..dc7cf0f2d61 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/MetalsEnrichments.scala
@@ -294,21 +294,13 @@ object MetalsEnrichments
       }
     }
 
-    def exists: Boolean = {
-      Files.exists(path.toNIO)
-    }
-
     def touch(): Unit = {
       if (!path.exists) {
-        parent.createDirectories()
+        path.parent.createDirectories()
         Files.createFile(path.toNIO)
       }
     }
 
-    def parent: AbsolutePath = {
-      AbsolutePath(path.toNIO.getParent)
-    }
-
     def createDirectories(): AbsolutePath = {
       AbsolutePath(Files.createDirectories(dealias.toNIO))
     }
@@ -318,10 +310,9 @@ object MetalsEnrichments
     }
 
     def writeText(text: String): Unit = {
-      parent.createDirectories()
+      path.parent.createDirectories()
       Files.write(path.toNIO, text.getBytes(StandardCharsets.UTF_8))
     }
-
   }
 
   implicit class XtensionString(value: String) {
diff --git a/metals/src/main/scala/scala/meta/internal/metals/MetalsLanguageServer.scala b/metals/src/main/scala/scala/meta/internal/metals/MetalsLanguageServer.scala
index c62c20ac898..954b86bd0f1 100644
--- a/metals/src/main/scala/scala/meta/internal/metals/MetalsLanguageServer.scala
+++ b/metals/src/main/scala/scala/meta/internal/metals/MetalsLanguageServer.scala
@@ -1316,7 +1316,7 @@ class MetalsLanguageServer(
   private def indexWorkspaceSources(): Unit = {
     for {
       (sourceItem, targets) <- buildTargets.sourceItemsToBuildTargets
-      source <- WalkFiles(sourceItem)
+      source <- sourceItem.listRecursive
       if source.isScalaOrJava
     } {
       targets.asScala.foreach { target =>
diff --git a/metals/src/main/scala/scala/meta/internal/tvp/ClasspathSymbols.scala b/metals/src/main/scala/scala/meta/internal/tvp/ClasspathSymbols.scala
index 4ed74ceadee..98747356602 100644
--- a/metals/src/main/scala/scala/meta/internal/tvp/ClasspathSymbols.scala
+++ b/metals/src/main/scala/scala/meta/internal/tvp/ClasspathSymbols.scala
@@ -20,7 +20,6 @@ import scala.tools.scalap.scalax.rules.scalasig.SymbolInfoSymbol
 import scala.meta.internal.scalacp.SymlinkChildren
 import scala.meta.internal.scalacp.Synthetics
 import scala.util.control.NonFatal
-import java.util.stream.Collectors
 import scala.meta.internal.javacp.Javacp
 import scala.meta.internal.metals.Time
 import scala.meta.internal.metals.Timer
@@ -95,17 +94,16 @@ class ClasspathSymbols(isStatisticsEnabled: Boolean = false) {
     def list(root: AbsolutePath): Unit = {
       val dir =
         if (symbol == Scala.Symbols.RootPackage) root
-        else {
-          root.resolve(Symbol(symbol).enclosingPackage.value)
-        }
-      listPath(dir.toNIO).foreach { path =>
-        if (Files.isDirectory(path)) {
-          buf ++= dummyClassfiles(root.toNIO, path)
-        } else if (isClassfile(path)) {
+        else root.resolve(Symbol(symbol).enclosingPackage.value)
+
+      dir.list.foreach {
+        case path if path.isDirectory =>
+          buf ++= dummyClassfiles(root.toNIO, path.toNIO)
+
+        case path if isClassfile(path.toNIO) =>
           try {
-            val abspath = AbsolutePath(path)
-            val node = abspath.toClassNode
-            classfileSymbols(path, node, index, { i =>
+            val node = path.toClassNode
+            classfileSymbols(path.toNIO, node, index, { i =>
               if (isRelevant(i)) {
                 buf += TreeViewSymbolInformation(i.symbol, i.kind, i.properties)
               }
@@ -114,7 +112,8 @@ class ClasspathSymbols(isStatisticsEnabled: Boolean = false) {
             case NonFatal(ex) =>
               scribe.warn(s"error: can't convert $path in $in", ex)
           }
-        }
+
+        case _ =>
       }
 
     }
@@ -174,15 +173,6 @@ class ClasspathSymbols(isStatisticsEnabled: Boolean = false) {
   private def isClassfile(path: Path): Boolean = {
     PathIO.extension(path) == "class" && Files.size(path) > 0
   }
-  private def listPath(path: Path): Seq[Path] = {
-    if (Files.isDirectory(path)) {
-      val ls = Files.list(path)
-      try ls.collect(Collectors.toList()).asScala
-      finally ls.close()
-    } else {
-      Nil
-    }
-  }
 
   private def classfileSymbols(
       path: Path,
@@ -224,7 +214,6 @@ class ClasspathSymbols(isStatisticsEnabled: Boolean = false) {
           }
         }
     }
-    Nil
   }
 
 }
diff --git a/mtags/src/main/scala/scala/meta/internal/metals/JdkSources.scala b/mtags/src/main/scala/scala/meta/internal/metals/JdkSources.scala
index 4bee08c7b90..b4b272dcae7 100644
--- a/mtags/src/main/scala/scala/meta/internal/metals/JdkSources.scala
+++ b/mtags/src/main/scala/scala/meta/internal/metals/JdkSources.scala
@@ -1,16 +1,16 @@
 package scala.meta.internal.metals
 
-import java.nio.file.Files
-import java.nio.file.Path
 import java.nio.file.Paths
 import scala.meta.io.AbsolutePath
+import scala.meta.io.RelativePath
+import scala.meta.internal.mtags.MtagsEnrichments._
 
 /**
  * Locates zip file on disk that contains the source code for the JDK.
  */
 object JdkSources {
-  private val sources = Paths.get("src.zip")
-  private val libSources = Paths.get("lib").resolve(sources)
+  private val sources = RelativePath(Paths.get("src.zip"))
+  private val libSources = RelativePath(Paths.get("lib")).resolve(sources)
 
   def apply(userJavaHome: Option[String] = None): Option[AbsolutePath] = {
     candidates(userJavaHome).headOption
@@ -23,33 +23,32 @@ object JdkSources {
   }
 
   private def candidates(userJavaHome: Option[String]): List[AbsolutePath] = {
-    def isJdkCandidate(path: Path): Boolean = {
-      def containsJre = Files.exists(path.resolve("jre"))
-      val name = path.getFileName.toString
+    def isJdkCandidate(path: AbsolutePath): Boolean = {
+      def containsJre = path.resolve("jre").exists
+      val name = path.filename.toString
       name.contains("jdk") || containsJre //e.g. jdk-8, java-openjdk-11
     }
 
     for {
       javaHomeString <- userJavaHome.orElse(defaultJavaHome).toList
-      javaHome = Paths.get(javaHomeString)
+      javaHome = AbsolutePath(Paths.get(javaHomeString))
       jdkHome = {
         if (isJdkCandidate(javaHome)) {
           Nil
         } else {
           // In case java.home points to the JRE instead of the JDK,
           // try to find jdk among its siblings
-          Files
-            .list(javaHome.getParent)
+          javaHome.parent.list
             .filter(isJdkCandidate)
-            .toArray[Path](size => new Array(size))
-            .sortBy(_.getFileName)
+            .toArray[AbsolutePath]
+            .sortBy(_.filename)
             .toList
         }
       }
-      jdk <- jdkHome ++ List(javaHome.getParent, javaHome)
+      jdk <- jdkHome ++ List(javaHome.parent, javaHome)
       src <- List(sources, libSources).map(jdk.resolve)
-      if Files.isRegularFile(src)
-    } yield AbsolutePath(src)
+      if src.isFile
+    } yield src
   }
 
   def getOrThrow(): AbsolutePath = {
diff --git a/mtags/src/main/scala/scala/meta/internal/metals/PackageIndex.scala b/mtags/src/main/scala/scala/meta/internal/metals/PackageIndex.scala
index b3fda5f4b4c..62644ab3369 100644
--- a/mtags/src/main/scala/scala/meta/internal/metals/PackageIndex.scala
+++ b/mtags/src/main/scala/scala/meta/internal/metals/PackageIndex.scala
@@ -20,7 +20,6 @@ import scala.util.control.NonFatal
 import scala.util.Properties
 import java.nio.file.FileSystems
 import java.net.URI
-import scala.meta.internal.mtags.ListFiles
 
 /**
  * An index to lookup classfiles contained in a given classpath.
@@ -137,7 +136,7 @@ class PackageIndex() {
     for {
       pkg <- Files.newDirectoryStream(dir).iterator().asScala
       symbol = pkg.toString.stripPrefix("/packages/").replace('.', '/') + "/"
-      absoluteModuleLink <- ListFiles(AbsolutePath(pkg))
+      absoluteModuleLink <- AbsolutePath(pkg).list
     } {
       val moduleLink = absoluteModuleLink.toNIO
       val module =
diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/ListFiles.scala b/mtags/src/main/scala/scala/meta/internal/mtags/ListFiles.scala
deleted file mode 100644
index f2638c8bc28..00000000000
--- a/mtags/src/main/scala/scala/meta/internal/mtags/ListFiles.scala
+++ /dev/null
@@ -1,41 +0,0 @@
-package scala.meta.internal.mtags
-
-import java.nio.file.Files
-import scala.meta.io.AbsolutePath
-import scala.collection.mutable
-import java.util.stream.{Stream => JStream}
-import java.nio.file.Path
-
-object ListFiles {
-  def apply(root: AbsolutePath): mutable.ArrayBuffer[AbsolutePath] = {
-    val buf = mutable.ArrayBuffer.empty[AbsolutePath]
-    foreach(root)(file => buf += file)
-    buf
-  }
-
-  def exists(root: AbsolutePath)(fn: AbsolutePath => Boolean) =
-    closing(root) {
-      _.anyMatch(file => fn(AbsolutePath(file)))
-    }
-
-  def forall(root: AbsolutePath)(fn: AbsolutePath => Boolean) =
-    closing(root) {
-      _.allMatch(file => fn(AbsolutePath(file)))
-    }
-
-  def foreach(root: AbsolutePath)(fn: AbsolutePath => Unit) =
-    closing(root) {
-      _.forEach(file => fn(AbsolutePath(file)))
-    }
-
-  private def closing[T](
-      root: AbsolutePath
-  )(fn: JStream[Path] => T): T = {
-    val ls = Files.list(root.toNIO)
-    try {
-      fn(ls)
-    } finally {
-      ls.close()
-    }
-  }
-}
diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/MtagsEnrichments.scala b/mtags/src/main/scala/scala/meta/internal/mtags/MtagsEnrichments.scala
index 0e05bc2f914..c748c40ff7b 100644
--- a/mtags/src/main/scala/scala/meta/internal/mtags/MtagsEnrichments.scala
+++ b/mtags/src/main/scala/scala/meta/internal/mtags/MtagsEnrichments.scala
@@ -3,6 +3,7 @@ package scala.meta.internal.mtags
 import com.google.gson.Gson
 import com.google.gson.JsonElement
 import java.nio.charset.StandardCharsets
+import java.nio.file.Files
 import java.nio.file.Path
 import java.nio.file.Paths
 import java.util
@@ -10,6 +11,7 @@ import java.util.Optional
 import java.util.concurrent.CancellationException
 import java.util.logging.Level
 import java.util.logging.Logger
+import geny.Generator
 import org.eclipse.lsp4j.CompletionItem
 import org.eclipse.lsp4j.MarkupContent
 import org.eclipse.lsp4j.jsonrpc.CancelChecker
@@ -57,7 +59,9 @@ trait MtagsEnrichments {
     def isClassfile: Boolean = filename.endsWith(".class")
     def filename: String = file.getFileName().toString()
     def toLanguage: Language = {
-      filenameToLanguage(file.getFileName.toString)
+      val filename = file.getFileName
+      if (filename == null) Language.UNKNOWN_LANGUAGE
+      else filenameToLanguage(filename.toString)
     }
     def semanticdbRoot: Option[Path] = {
       val end = Paths.get("META-INF").resolve("semanticdb")
@@ -359,4 +363,32 @@ trait MtagsEnrichments {
     def isVar: Boolean = (properties & p.VAR.value) != 0
     def isVal: Boolean = (properties & p.VAL.value) != 0
   }
+
+  implicit class XtensionStream[A](stream: java.util.stream.Stream[A]) {
+    import scala.collection.JavaConverters._
+    def asScala: Generator[A] = {
+      Generator.selfClosing((stream.iterator.asScala, () => stream.close()))
+    }
+  }
+
+  implicit class XtensionAbsolutePath(path: AbsolutePath) {
+    def parent: AbsolutePath = {
+      AbsolutePath(path.toNIO.getParent)
+    }
+
+    def exists: Boolean = {
+      Files.exists(path.toNIO)
+    }
+
+    def list: Generator[AbsolutePath] = {
+      if (path.isDirectory) Files.list(path.toNIO).asScala.map(AbsolutePath(_))
+      else Generator()
+    }
+
+    def listRecursive: Generator[AbsolutePath] = {
+      if (path.isDirectory) Files.walk(path.toNIO).asScala.map(AbsolutePath(_))
+      else if (path.isFile) Generator(path)
+      else Generator()
+    }
+  }
 }
diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/OnDemandSymbolIndex.scala b/mtags/src/main/scala/scala/meta/internal/mtags/OnDemandSymbolIndex.scala
index 54f68ffc785..fa7db39218a 100644
--- a/mtags/src/main/scala/scala/meta/internal/mtags/OnDemandSymbolIndex.scala
+++ b/mtags/src/main/scala/scala/meta/internal/mtags/OnDemandSymbolIndex.scala
@@ -53,15 +53,15 @@ final case class OnDemandSymbolIndex(
   override def addSourceJar(jar: AbsolutePath): Unit = tryRun {
     if (sourceJars.addEntry(jar)) {
       FileIO.withJarFileSystem(jar, create = false) { root =>
-        WalkFiles.foreach(root) { source =>
-          if (source.toLanguage.isScala) {
+        root.listRecursive.foreach {
+          case source if source.isScala =>
             try {
               addSourceFile(source, None)
             } catch {
               case NonFatal(e) =>
                 onError.lift(IndexError(source, e))
             }
-          }
+          case _ =>
         }
       }
     }
diff --git a/mtags/src/main/scala/scala/meta/internal/mtags/WalkFiles.scala b/mtags/src/main/scala/scala/meta/internal/mtags/WalkFiles.scala
deleted file mode 100644
index 56d7cb02b3f..00000000000
--- a/mtags/src/main/scala/scala/meta/internal/mtags/WalkFiles.scala
+++ /dev/null
@@ -1,41 +0,0 @@
-package scala.meta.internal.mtags
-
-import java.nio.file.FileVisitResult
-import java.nio.file.Files
-import java.nio.file.NoSuchFileException
-import java.nio.file.Path
-import java.nio.file.SimpleFileVisitor
-import java.nio.file.attribute.BasicFileAttributes
-import scala.meta.io.AbsolutePath
-import scala.collection.mutable.ArrayBuffer
-
-object WalkFiles {
-  def foreach(root: AbsolutePath)(fn: AbsolutePath => Unit): Unit = {
-    if (root.isFile) fn(root)
-    else if (root.isDirectory) {
-      try {
-        Files.walkFileTree(
-          root.toNIO,
-          new SimpleFileVisitor[Path] {
-            override def visitFile(
-                file: Path,
-                attrs: BasicFileAttributes
-            ): FileVisitResult = {
-              fn(AbsolutePath(file))
-              FileVisitResult.CONTINUE
-            }
-          }
-        )
-      } catch {
-        case _: NoSuchFileException =>
-          () // error is reported by the JDK
-      }
-    }
-  }
-
-  def apply(root: AbsolutePath): ArrayBuffer[AbsolutePath] = {
-    val buf = ArrayBuffer.empty[AbsolutePath]
-    foreach(root)(file => buf += file)
-    buf
-  }
-}
diff --git a/tests/unit/src/main/scala/tests/QuickBuild.scala b/tests/unit/src/main/scala/tests/QuickBuild.scala
index 97b67c47a72..0f81227c4d0 100644
--- a/tests/unit/src/main/scala/tests/QuickBuild.scala
+++ b/tests/unit/src/main/scala/tests/QuickBuild.scala
@@ -21,7 +21,6 @@ import scala.meta.internal.metals.{BuildInfo => V}
 import scala.meta.internal.mtags.MD5
 import scala.meta.io.AbsolutePath
 import scala.util.matching.Regex
-import scala.meta.internal.mtags.ListFiles
 
 /**
  * A basic build tool for faster testing.
@@ -269,11 +268,9 @@ object QuickBuild {
       update(workspace.resolve("metals.json"))
       val bloopDirectory = workspace.resolve(".bloop").toNIO
       Files.createDirectories(bloopDirectory)
-      ListFiles.foreach(AbsolutePath(bloopDirectory)) { path =>
-        if (path.extension == "json") {
-          update(path)
-        }
-      }
+      AbsolutePath(bloopDirectory).list
+        .filter(_.extension == "json")
+        .foreach(json => update(json))
       MD5.bytesToHex(digest.digest())
     }
     if (oldDigest == newDigest) None
@@ -297,11 +294,9 @@ object QuickBuild {
           }
           val bloopDirectory = workspace.resolve(".bloop").toNIO
           Files.createDirectories(bloopDirectory)
-          ListFiles.foreach(AbsolutePath(bloopDirectory)) { path =>
-            if (path.extension == "json") {
-              path.delete()
-            }
-          }
+          AbsolutePath(bloopDirectory).list
+            .filter(_.extension == "json")
+            .foreach(json => json.delete())
           val bloopProjects = projects.map(_.toBloop(workspace))
           val byName = bloopProjects.map(p => p.name -> p).toMap
           val fullClasspathProjects = bloopProjects.map { p =>