diff --git a/platform/ide-core-impl/src/com/intellij/openapi/vfs/local/PluggableFileWatcher.java b/platform/ide-core-impl/src/com/intellij/openapi/vfs/local/PluggableFileWatcher.java
index e91675615a12..cbc153810093 100644
--- a/platform/ide-core-impl/src/com/intellij/openapi/vfs/local/PluggableFileWatcher.java
+++ b/platform/ide-core-impl/src/com/intellij/openapi/vfs/local/PluggableFileWatcher.java
@@ -1,4 +1,4 @@
-// Copyright 2000-2021 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.openapi.vfs.local;
 
 import com.intellij.openapi.extensions.ExtensionPointName;
@@ -9,9 +9,6 @@ import org.jetbrains.annotations.TestOnly;
 import java.io.IOException;
 import java.util.List;
 
-/**
- * @author dslomov
- */
 public abstract class PluggableFileWatcher {
   public static final ExtensionPointName<PluggableFileWatcher> EP_NAME =
     ExtensionPointName.create("com.intellij.vfs.local.pluggableFileWatcher");
@@ -26,6 +23,8 @@ public abstract class PluggableFileWatcher {
 
   /**
    * The inputs to this method must be absolute and free of symbolic links.
+   *
+   * @implNote An implementation <b>must report</b> paths it doesn't recognize via {@link FileWatcherNotificationSink#notifyManualWatchRoots}.
    */
   public abstract void setWatchRoots(@NotNull List<String> recursive, @NotNull List<String> flat);
 
diff --git a/platform/platform-tests/testSrc/com/intellij/openapi/vfs/local/WslFileWatcherTest.kt b/platform/platform-tests/testSrc/com/intellij/openapi/vfs/local/WslFileWatcherTest.kt
index 83738beb9836..798a9595c4ef 100644
--- a/platform/platform-tests/testSrc/com/intellij/openapi/vfs/local/WslFileWatcherTest.kt
+++ b/platform/platform-tests/testSrc/com/intellij/openapi/vfs/local/WslFileWatcherTest.kt
@@ -1,4 +1,4 @@
-// Copyright 2000-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file.
+// Copyright 2000-2022 JetBrains s.r.o. and contributors. Use of this source code is governed by the Apache 2.0 license.
 package com.intellij.openapi.vfs.local
 
 import com.intellij.execution.configurations.GeneralCommandLine
@@ -123,12 +123,11 @@ class WslFileWatcherTest : BareTestFixtureTestCase() {
 
   @Test fun testFileRoot() {
     val files = arrayOf(tempDir.newFile("test1.txt"), tempDir.newFile("test2.txt"))
-    files.forEach { refresh(it) }
-    files.forEach { watch(it, false) }
+    files.forEach { refresh(it); watch(it, false) }
 
-    assertEvents({ files.forEach { it.writeText("new content") } }, files.map { it to 'U' }.toMap())
-    assertEvents({ files.forEach { assertTrue(it.delete()) } }, files.map { it to 'D' }.toMap())
-    assertEvents({ files.forEach { it.writeText("re-creation") } }, files.map { it to 'C' }.toMap())
+    assertEvents({ files.forEach { it.writeText("new content") } }, files.associateWith { 'U' })
+    assertEvents({ files.forEach { assertTrue(it.delete()) } }, files.associateWith { 'D' })
+    assertEvents({ files.forEach { it.writeText("re-creation") } }, files.associateWith { 'C' })
   }
 
   @Test fun testFileRootRecursive() {
@@ -136,9 +135,9 @@ class WslFileWatcherTest : BareTestFixtureTestCase() {
     files.forEach { refresh(it) }
     files.forEach { watch(it, true) }
 
-    assertEvents({ files.forEach { it.writeText("new content") } }, files.map { it to 'U' }.toMap())
-    assertEvents({ files.forEach { assertTrue(it.delete()) } }, files.map { it to 'D' }.toMap())
-    assertEvents({ files.forEach { it.writeText("re-creation") } }, files.map { it to 'C' }.toMap())
+    assertEvents({ files.forEach { it.writeText("new content") } }, files.associateWith { 'U' })
+    assertEvents({ files.forEach { assertTrue(it.delete()) } }, files.associateWith { 'D' })
+    assertEvents({ files.forEach { it.writeText("re-creation") } }, files.associateWith { 'C' })
   }
 
   @Test fun testDirectoryRecursive() {