diff --git a/platform/platform-api/src/com/intellij/util/Url.java b/platform/platform-api/src/com/intellij/util/Url.java
index 81b824fbb568..dc776a096d58 100644
--- a/platform/platform-api/src/com/intellij/util/Url.java
+++ b/platform/platform-api/src/com/intellij/util/Url.java
@@ -15,6 +15,7 @@
  */
 package com.intellij.util;
 
+import org.jetbrains.annotations.Contract;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
 
@@ -28,6 +29,7 @@ public interface Url {
   @NotNull
   String getPath();
 
+  @Contract(pure = true)
   boolean isInLocalFileSystem();
 
   String toDecodedForm();