diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.31.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.31.kt
new file mode 100644
index 000000000..57d16cb4c
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.31.kt
@@ -0,0 +1,20 @@
+//sampleStart
+fun getStringLength(obj: Any): Int? {
+    if (obj is String) {
+        // `obj` is automatically cast to `String` in this branch
+        return obj.length
+    }
+
+    // `obj` is still of type `Any` outside of the type-checked branch
+    return null
+}
+//sampleEnd
+
+fun main() {
+    fun printLength(obj: Any) {
+        println("Getting the length of '$obj'. Result: ${getStringLength(obj) ?: "Error: The object is not a string"} ")
+    }
+    printLength("Incomprehensibilities")
+    printLength(1000)
+    printLength(listOf(Any()))
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.33.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.33.kt
new file mode 100644
index 000000000..be0298249
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-syntax/5ec261721162729866abc1e8f7293ef4.33.kt
@@ -0,0 +1,19 @@
+//sampleStart
+fun getStringLength(obj: Any): Int? {
+    // `obj` is automatically cast to `String` on the right-hand side of `&&`
+    if (obj is String && obj.length >= 0) {
+        return obj.length
+    }
+
+    return null
+}
+//sampleEnd
+
+fun main() {
+    fun printLength(obj: Any) {
+        println("Getting the length of '$obj'. Result: ${getStringLength(obj) ?: "Error: The object is not a string"} ")
+    }
+    printLength("Incomprehensibilities")
+    printLength("")
+    printLength(1000)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.1.kt
deleted file mode 100644
index 144af42b1..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.1.kt
+++ /dev/null
@@ -1,14 +0,0 @@
-fun main() {
-//sampleStart
-    val a: Int = 100
-    val boxedA: Int? = a
-    val anotherBoxedA: Int? = a
-    
-    val b: Int = 10000
-    val boxedB: Int? = b
-    val anotherBoxedB: Int? = b
-    
-    println(boxedA === anotherBoxedA) // true
-    println(boxedB === anotherBoxedB) // false
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.10.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.10.kt
deleted file mode 100644
index dfa601050..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.10.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-fun main() {
-val str = "abcd"
-//sampleStart
-for (c in str) {
-    println(c)
-}
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.11.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.11.kt
deleted file mode 100644
index fba1c3f67..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.11.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-fun main() {
-//sampleStart
-    val str = "abcd"
-    println(str.uppercase()) // Create and print a new String object
-    println(str) // the original string remains the same
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.12.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.12.kt
deleted file mode 100644
index 0c69b6674..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.12.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-fun main() {
-//sampleStart
-val s = "abc" + 1
-println(s + "def")
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.13.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.13.kt
deleted file mode 100644
index 13b6321a8..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.13.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-fun main() {
-//sampleStart
-    val i = 10
-    println("i = $i") // prints "i = 10"
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.14.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.14.kt
deleted file mode 100644
index 05e19fd86..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.14.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-fun main() {
-//sampleStart
-    val s = "abc"
-    println("$s.length is ${s.length}") // prints "abc.length is 3"
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.15.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.15.kt
deleted file mode 100644
index 2800fbc61..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.15.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-fun main() {
-//sampleStart
-    // Creates an Array<String> with values ["0", "1", "4", "9", "16"]
-    val asc = Array(5) { i -> (i * i).toString() }
-    asc.forEach { println(it) }
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.2.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.2.kt
deleted file mode 100644
index cb68919a9..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.2.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-fun main() {
-//sampleStart
-    val b: Int = 10000
-    println(b == b) // Prints 'true'
-    val boxedB: Int? = b
-    val anotherBoxedB: Int? = b
-    println(boxedB == anotherBoxedB) // Prints 'true'
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.3.kt
deleted file mode 100644
index e172907c4..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.3.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-fun main() {
-//sampleStart
-    val b: Byte = 1 // OK, literals are checked statically
-    // val i: Int = b // ERROR
-    val i1: Int = b.toInt()
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.4.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.4.kt
deleted file mode 100644
index 33031c01d..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.4.kt
+++ /dev/null
@@ -1,8 +0,0 @@
-fun main() {
-//sampleStart
-    println(1 + 2)
-    println(2_500_000_000L - 1L)
-    println(3.14 * 2.71)
-    println(10.0 / 3)
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.5.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.5.kt
deleted file mode 100644
index b1b733f07..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.5.kt
+++ /dev/null
@@ -1,7 +0,0 @@
-fun main() {
-//sampleStart
-    val x = 5 / 2
-    //println(x == 2.5) // ERROR: Operator '==' cannot be applied to 'Int' and 'Double'
-    println(x == 2)
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.6.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.6.kt
deleted file mode 100644
index 5a3782fdd..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.6.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-fun main() {
-//sampleStart
-    val x = 5L / 2
-    println(x == 2L)
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.7.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.7.kt
deleted file mode 100644
index 16e0201c3..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.7.kt
+++ /dev/null
@@ -1,6 +0,0 @@
-fun main() {
-//sampleStart
-    val x = 5 / 2.toDouble()
-    println(x == 2.5)
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.8.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.8.kt
deleted file mode 100644
index 04c96d807..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.8.kt
+++ /dev/null
@@ -1,11 +0,0 @@
-fun main() {
-//sampleStart
-    val myTrue: Boolean = true
-    val myFalse: Boolean = false
-    val boolNull: Boolean? = null
-    
-    println(myTrue || myFalse)
-    println(myTrue && myFalse)
-    println(!myTrue)
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.9.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.9.kt
deleted file mode 100644
index 272e33cd0..000000000
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/basic-types/be5678589cf16c80d1cda9c85d9a55d9.9.kt
+++ /dev/null
@@ -1,9 +0,0 @@
-fun main() {
-//sampleStart
-    val aChar: Char = 'a'
- 
-    println(aChar)
-    println('\n') //prints an extra newline character
-    println('\uFF00')
-//sampleEnd
-}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.1.kt
index 342555a69..f0451009a 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.1.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.1.kt
@@ -1,15 +1,14 @@
-fun main() {
+fun main() { 
 //sampleStart
-    open class Shape
-    class Rectangle: Shape()
-    
-    fun Shape.getName() = "Shape"
-    fun Rectangle.getName() = "Rectangle"
-    
-    fun printClassName(s: Shape) {
-        println(s.getName())
-    }
-    
-    printClassName(Rectangle())
-//sampleEnd
-}
\ No newline at end of file
+    // builder is an instance of StringBuilder
+    val builder = StringBuilder()
+        // Calls .appendLine() extension function on builder
+        .appendLine("Hello")
+        .appendLine()
+        .appendLine("World")
+    println(builder.toString())
+    // Hello
+    //
+    // World
+}
+//sampleEnd
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.10.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.10.kt
new file mode 100644
index 000000000..882f7991a
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.10.kt
@@ -0,0 +1,10 @@
+fun main() {
+    //sampleStart
+    data class Order(val weight: Double)
+    val calculateShipping = fun Order.(rate: Double): Double = this.weight * rate
+    
+    val order = Order(2.5)
+    val cost = order.calculateShipping(3.0)
+    println("Shipping cost: $cost") 
+    // Shipping cost: 7.5
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.11.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.11.kt
new file mode 100644
index 000000000..99b985c8e
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.11.kt
@@ -0,0 +1,8 @@
+fun main() {
+    val isInRange: Int.(min: Int, max: Int) -> Boolean = { min, max -> this in min..max }
+
+    println(5.isInRange(1, 10))
+    // true
+    println(20.isInRange(1, 10))
+    // false
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.12.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.12.kt
new file mode 100644
index 000000000..f3bba5aec
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.12.kt
@@ -0,0 +1,12 @@
+data class User(val firstName: String, val lastName: String)
+
+// An extension property to get a username-style email handle
+val User.emailUsername: String
+    get() = "${firstName.lowercase()}.${lastName.lowercase()}"
+
+fun main() {
+    val user = User("Mickey", "Mouse")
+    // Calls extension property
+    println("Generated email username: ${user.emailUsername}")
+    // Generated email username: mickey.mouse
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.13.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.13.kt
new file mode 100644
index 000000000..6ccbd9066
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.13.kt
@@ -0,0 +1,29 @@
+data class House(val streetName: String)
+
+// Doesn't compile because there is no getter and setter
+// var House.number = 1
+// Error: Initializers are not allowed for extension properties
+
+// Compiles successfully
+val houseNumbers = mutableMapOf<House, Int>()
+var House.number: Int
+    get() = houseNumbers[this] ?: 1
+    set(value) {
+        println("Setting house number for ${this.streetName} to $value")
+        houseNumbers[this] = value
+    }
+
+fun main() {
+    val house = House("Maple Street")
+
+    // Shows the default
+    println("Default number: ${house.number} ${house.streetName}") 
+    // Default number: 1 Maple Street
+    
+    house.number = 99
+    // Setting house number for Maple Street to 99
+
+    // Shows the updated number
+    println("Updated number: ${house.number} ${house.streetName}") 
+    // Updated number: 99 Maple Street
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.14.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.14.kt
new file mode 100644
index 000000000..5c89ee901
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.14.kt
@@ -0,0 +1,12 @@
+class Logger {
+    companion object { }
+}
+
+fun Logger.Companion.logStartupMessage() {
+    println("Application started.")
+}
+
+fun main() {
+    Logger.logStartupMessage()
+    // Application started.
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.15.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.15.kt
new file mode 100644
index 000000000..654eed807
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.15.kt
@@ -0,0 +1,32 @@
+class Host(val hostname: String) {
+    fun printHostname() { print(hostname) }
+}
+
+class Connection(val host: Host, val port: Int) {
+    fun printPort() { print(port) }
+
+    // Host is the extension receiver
+    fun Host.printConnectionString() {
+        // Calls Host.printHostname()
+        printHostname() 
+        print(":")
+        // Calls Connection.printPort()
+        // Connection is the dispatch receiver
+        printPort()
+    }
+
+    fun connect() {
+        /*...*/
+        // Calls the extension function
+        host.printConnectionString() 
+    }
+}
+
+fun main() {
+    Connection(Host("kotl.in"), 443).connect()
+    // kotl.in:443
+    
+    // Triggers an error because the extension function isn't available outside Connection
+    // Host("kotl.in").printConnectionString()
+    // Unresolved reference 'printConnectionString'.
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.16.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.16.kt
new file mode 100644
index 000000000..a48768481
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.16.kt
@@ -0,0 +1,48 @@
+open class User
+
+class Admin : User()
+
+open class NotificationSender {
+    open fun User.sendNotification() {
+        println("Sending user notification from normal sender")
+    }
+
+    open fun Admin.sendNotification() {
+        println("Sending admin notification from normal sender")
+    }
+
+    fun notify(user: User) {
+        user.sendNotification()
+    }
+}
+
+class SpecialNotificationSender : NotificationSender() {
+    override fun User.sendNotification() {
+        println("Sending user notification from special sender")
+    }
+
+    override fun Admin.sendNotification() {
+        println("Sending admin notification from special sender")
+    }
+}
+
+fun main() {
+    // Dispatch receiver is NotificationSender
+    // Extension receiver is User
+    // Resolves to User.sendNotification() in NotificationSender
+    NotificationSender().notify(User())
+    // Sending user notification from normal sender
+    
+    // Dispatch receiver is SpecialNotificationSender
+    // Extension receiver is User
+    // Resolves to User.sendNotification() in SpecialNotificationSender
+    SpecialNotificationSender().notify(User())
+    // Sending user notification from special sender 
+    
+    // Dispatch receiver is SpecialNotificationSender
+    // Extension receiver is User NOT Admin
+    // The notify() function declares user as type User
+    // Statically resolves to User.sendNotification() in SpecialNotificationSender
+    SpecialNotificationSender().notify(Admin())
+    // Sending user notification from special sender 
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.17.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.17.kt
new file mode 100644
index 000000000..0a35d1e7f
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.17.kt
@@ -0,0 +1,20 @@
+// File: StringUtils.kt
+
+private fun removeWhitespace(input: String): String {
+    return input.replace("\\s".toRegex(), "")
+}
+
+fun String.cleaned(): String {
+    return removeWhitespace(this)
+}
+
+fun main() {
+    val rawEmail = "  user @example. com  "
+    val cleaned = rawEmail.cleaned()
+    println("Raw:     '$rawEmail'")
+    // Raw:     '  user @example. com  '
+    println("Cleaned: '$cleaned'")
+    // Cleaned: 'user@example.com'
+    println("Looks like an email: ${cleaned.contains("@") && cleaned.contains(".")}") 
+    // Looks like an email: true
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.18.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.18.kt
new file mode 100644
index 000000000..2a36a986d
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.18.kt
@@ -0,0 +1,19 @@
+class User(private val password: String) {
+    fun isLoggedIn(): Boolean = true
+    fun passwordLength(): Int = password.length
+}
+
+// Extension declared outside the class
+fun User.isSecure(): Boolean {
+    // Can't access password because it's private:
+    // return password.length >= 8
+
+    // Instead, we rely on public members:
+    return passwordLength() >= 8 && isLoggedIn()
+}
+
+fun main() {
+    val user = User("supersecret")
+    println("Is user secure: ${user.isSecure()}") 
+    // Is user secure: true
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.2.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.2.kt
index a478042e0..2b2395054 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.2.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.2.kt
@@ -1,11 +1,13 @@
+fun String.truncate(maxLength: Int): String {
+    return if (this.length <= maxLength) this else take(maxLength - 3) + "..."
+}
+
 fun main() {
-//sampleStart
-    class Example {
-        fun printFunctionType() { println("Class method") }
-    }
-    
-    fun Example.printFunctionType() { println("Extension function") }
-    
-    Example().printFunctionType()
-//sampleEnd
+    val shortUsername = "KotlinFan42"
+    val longUsername = "JetBrainsLoverForever"
+
+    println("Short username: ${shortUsername.truncate(15)}") 
+    // KotlinFan42
+    println("Long username:  ${longUsername.truncate(15)}")
+    // JetBrainsLov...
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.3.kt
index e08257e40..e60dea737 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.3.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.3.kt
@@ -1,11 +1,15 @@
+interface User {
+    val name: String
+    val email: String
+}
+
+fun User.displayInfo(): String = "User(name=$name, email=$email)"
+
+// Inherits from and implements the properties of the User interface
+class RegularUser(override val name: String, override val email: String) : User
+
 fun main() {
-//sampleStart
-    class Example {
-        fun printFunctionType() { println("Class method") }
-    }
-    
-    fun Example.printFunctionType(i: Int) { println("Extension function #$i") }
-    
-    Example().printFunctionType(1)
-//sampleEnd
+    val user = RegularUser("Alice", "alice@example.com")
+    println(user.displayInfo()) 
+    // User(name=Alice, email=alice@example.com)
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.4.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.4.kt
index 0252a3ece..b4d06877b 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.4.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.4.kt
@@ -1,9 +1,14 @@
-class MyClass {
-    companion object { }  // will be called "Companion"
+fun Map<String, Int>.mostVoted(): String? {
+    return maxByOrNull { (key, value) -> value }?.key
 }
 
-fun MyClass.Companion.printCompanion() { println("companion") }
-
 fun main() {
-    MyClass.printCompanion()
+    val poll = mapOf(
+        "Cats" to 37,
+        "Dogs" to 58,
+        "Birds" to 22
+    )
+
+    println("Top choice: ${poll.mostVoted()}") 
+    // Dogs
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.5.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.5.kt
index 33933bde6..851f8dcb7 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.5.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.5.kt
@@ -1,23 +1,16 @@
-class Host(val hostname: String) {
-    fun printHostname() { print(hostname) }
+fun <T> List<T>.endpoints(): Pair<T, T> {
+    return first() to last()
 }
 
-class Connection(val host: Host, val port: Int) {
-    fun printPort() { print(port) }
-
-    fun Host.printConnectionString() {
-        printHostname()   // calls Host.printHostname()
-        print(":")
-        printPort()   // calls Connection.printPort()
-    }
+fun main() {
+    val cities = listOf("Paris", "London", "Berlin", "Prague")
+    val temperatures = listOf(21.0, 19.5, 22.3)
 
-    fun connect() {
-        /*...*/
-        host.printConnectionString()   // calls the extension function
-    }
-}
+    val cityEndpoints = cities.endpoints()
+    val tempEndpoints = temperatures.endpoints()
 
-fun main() {
-    Connection(Host("kotl.in"), 443).connect()
-    //Host("kotl.in").printConnectionString()  // error, the extension function is unavailable outside Connection
+    println("First and last cities: $cityEndpoints")
+    // (Paris, Prague)
+    println("First and last temperatures: $tempEndpoints") 
+    // (21.0, 22.3)
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.6.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.6.kt
index 5dbc58e61..122d36319 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.6.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.6.kt
@@ -1,33 +1,19 @@
-open class Base { }
-
-class Derived : Base() { }
-
-open class BaseCaller {
-    open fun Base.printFunctionInfo() {
-        println("Base extension function in BaseCaller")
-    }
-
-    open fun Derived.printFunctionInfo() {
-        println("Derived extension function in BaseCaller")
-    }
-
-    fun call(b: Base) {
-        b.printFunctionInfo()   // call the extension function
-    }
-}
-
-class DerivedCaller: BaseCaller() {
-    override fun Base.printFunctionInfo() {
-        println("Base extension function in DerivedCaller")
-    }
-
-    override fun Derived.printFunctionInfo() {
-        println("Derived extension function in DerivedCaller")
-    }
-}
-
 fun main() {
-    BaseCaller().call(Base())   // "Base extension function in BaseCaller"
-    DerivedCaller().call(Base())  // "Base extension function in DerivedCaller" - dispatch receiver is resolved virtually
-    DerivedCaller().call(Derived())  // "Base extension function in DerivedCaller" - extension receiver is resolved statically
+    //sampleStart
+    // Extension function on nullable Any
+    fun Any?.toString(): String {
+        if (this == null) return "null"
+        // After null check, `this` is smart-cast to non-nullable Any
+        // So this call resolves to the regular toString() function
+        return toString()
+    }
+    
+    val number: Int? = 42
+    val nothing: Any? = null
+    
+    println(number.toString())
+    // 42
+    println(nothing.toString()) 
+    // null
+    //sampleEnd
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.7.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.7.kt
new file mode 100644
index 000000000..135329102
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.7.kt
@@ -0,0 +1,16 @@
+fun main() {
+//sampleStart
+    open class Shape
+    class Rectangle: Shape()
+    
+    fun Shape.getName() = "Shape"
+    fun Rectangle.getName() = "Rectangle"
+    
+    fun printClassName(shape: Shape) {
+        println(shape.getName())
+    }
+    
+    printClassName(Rectangle())
+    // Shape
+//sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.8.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.8.kt
new file mode 100644
index 000000000..1285d00a6
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.8.kt
@@ -0,0 +1,12 @@
+fun main() {
+//sampleStart
+    class Example {
+        fun printFunctionType() { println("Member function") }
+    }
+    
+    fun Example.printFunctionType() { println("Extension function") }
+    
+    Example().printFunctionType()
+    // Member function
+//sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.9.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.9.kt
new file mode 100644
index 000000000..de510ff4e
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/extensions/433cd94fef7d8fc09ee6e9ca8379b874.9.kt
@@ -0,0 +1,13 @@
+fun main() {
+//sampleStart
+    class Example {
+        fun printFunctionType() { println("Member function") }
+    }
+    
+    // Same name but different signature
+    fun Example.printFunctionType(index: Int) { println("Extension function #$index") }
+    
+    Example().printFunctionType(1)
+    // Extension function #1
+//sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/fun-interfaces/6c48fe77f81f41caaaf4ef9b586c27b9.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/fun-interfaces/6c48fe77f81f41caaaf4ef9b586c27b9.1.kt
index 27f8d4439..e5124b676 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/fun-interfaces/6c48fe77f81f41caaaf4ef9b586c27b9.1.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/fun-interfaces/6c48fe77f81f41caaaf4ef9b586c27b9.1.kt
@@ -1,9 +1,9 @@
 fun interface IntPredicate {
-   fun accept(i: Int): Boolean
+    fun accept(i: Int): Boolean
 }
 
 val isEven = IntPredicate { it % 2 == 0 }
 
 fun main() {
-   println("Is 7 even? - ${isEven.accept(7)}")
+    println("Is 7 even? - ${isEven.accept(7)}")
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.1.kt
new file mode 100644
index 000000000..a783d3b9b
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.1.kt
@@ -0,0 +1,15 @@
+fun main () {
+//sampleStart    
+fun greeting(
+    userId: Int = 0,
+    message: () -> Unit,
+)
+{ println(userId)
+  message() }
+    
+// Uses the default value for 'userId'
+greeting() { println ("Hello!") }
+// 0
+// Hello!
+//sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.2.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.2.kt
new file mode 100644
index 000000000..9e795ec29
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.2.kt
@@ -0,0 +1,13 @@
+fun main() {
+//sampleStart
+    fun read(
+        b: Int,
+        print: Unit? = println("No argument passed for 'print'")
+    ) { println(b) }
+    
+    // Prints "No argument passed for 'print'", then "1"
+    read(1)
+    // Prints only "1"
+    read(1, null)
+    //sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.3.kt
new file mode 100644
index 000000000..02f9066ce
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.3.kt
@@ -0,0 +1,20 @@
+fun main() {
+    //sampleStart
+    fun log(
+        level: Int = 0,
+        code:  Int = 1,
+        action: () -> Unit,
+    ) { println (level)
+        println (code)
+        action() }
+    
+    // Passes 1 for 'level' and uses the default value 1 for 'code'
+    log(1) { println("Connection established") }
+    
+    // Uses both default values, 0 for 'level' and 1 for 'code'
+    log(action = { println("Connection established") })
+    
+    // Equivalent to the previous call, uses both default values
+    log { println("Connection established") }
+    //sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.4.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.4.kt
new file mode 100644
index 000000000..8d78fc979
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.4.kt
@@ -0,0 +1,27 @@
+class MyStringCollection {
+    val items = mutableListOf<String>()
+
+    infix fun add(s: String) {
+        println("Adding: $s")
+        items += s
+    }
+
+    fun build() {
+        add("first")      // Correct: ordinary function call
+        this add "second" // Correct: infix call with an explicit receiver
+        // add "third"    // Compiler error: needs an explicit receiver
+    }
+
+    fun printAll() = println("Items = $items")
+}
+
+fun main() {
+    val myStrings = MyStringCollection()
+    // Adds "first" and "second" to the list twice
+    myStrings.build()
+      
+    myStrings.printAll()
+    // Adding: first
+    // Adding: second
+    // Items = [first, second]
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.5.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.5.kt
new file mode 100644
index 000000000..f684499b8
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.5.kt
@@ -0,0 +1,25 @@
+class Person(val name: String) {
+    val friends = mutableListOf<Person>()
+}
+class SocialGraph(val people: List<Person>)
+//sampleStart
+fun dfs(graph: SocialGraph) {
+    fun dfs(current: Person, visited: MutableSet<Person>) {
+        if (!visited.add(current)) return
+        println("Visited ${current.name}")
+        for (friend in current.friends)
+            dfs(friend, visited)
+    }
+    dfs(graph.people[0], HashSet())
+}
+//sampleEnd
+fun main() {
+    val alice = Person("Alice")
+    val bob = Person("Bob")
+    val charlie = Person("Charlie")
+    alice.friends += bob
+    bob.friends += charlie
+    charlie.friends += alice
+    val network = SocialGraph(listOf(alice, bob, charlie))
+    dfs(network)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.6.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.6.kt
new file mode 100644
index 000000000..9b8167556
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/functions/0e665030c5b12d50d2cadbb175fb3d8c.6.kt
@@ -0,0 +1,26 @@
+class Person(val name: String) {
+    val friends = mutableListOf<Person>()
+}
+class SocialGraph(val people: List<Person>)
+//sampleStart
+fun dfs(graph: SocialGraph) {
+    val visited = HashSet<Person>()
+    fun dfs(current: Person) {
+        if (!visited.add(current)) return
+        println("Visited ${current.name}")
+        for (friend in current.friends)
+            dfs(friend)
+    }
+    dfs(graph.people[0])
+}
+//sampleEnd
+fun main() {
+    val alice = Person("Alice")
+    val bob = Person("Bob")
+    val charlie = Person("Charlie")
+    alice.friends += bob
+    bob.friends += charlie
+    charlie.friends += alice
+    val network = SocialGraph(listOf(alice, bob, charlie))
+    dfs(network)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.3.kt
index dc0ffccbc..12c9f56cc 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.3.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.3.kt
@@ -2,7 +2,10 @@ class Client() {
     var token: String? = null
     fun connect() = println("connected!")
     fun authenticate() = println("authenticated!")
-    fun getData(): String = "Mock data"
+    fun getData() : String {
+        println("getting data!")
+        return "Mock data"
+    }
 }
 
 val client = Client()
@@ -14,4 +17,5 @@ fun main() {
     client.authenticate()
     // authenticated!
     client.getData()
+    // getting data!
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.4.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.4.kt
index 9be33babf..ca2ed22fa 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.4.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.4.kt
@@ -2,18 +2,22 @@ class Client() {
     var token: String? = null
     fun connect() = println("connected!")
     fun authenticate() = println("authenticated!")
-    fun getData(): String = "Mock data"
+    fun getData() : String {
+        println("getting data!")
+        return "Mock data"
+    }
 }
 //sampleStart
 val client = Client().apply {
     token = "asdf"
     connect()
+    // connected!
     authenticate()
+    // authenticated!
 }
 
 fun main() {
     client.getData()
-    // connected!
-    // authenticated!
+    // getting data!
 }
 //sampleEnd
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.5.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.5.kt
index 923fdccdf..e06de0466 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.5.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/kotlin-tour-intermediate-scope-functions/5ddc626d44be3297d9e5c8e32c63fa4c.5.kt
@@ -2,7 +2,10 @@ class Client() {
     var token: String? = null
     fun connect() = println("connected!")
     fun authenticate() = println("authenticated!")
-    fun getData(): String = "Mock data"
+    fun getData() : String {
+        println("getting data!")
+        return "Mock data"
+    }
 }
 
 //sampleStart
@@ -17,6 +20,7 @@ fun main() {
         authenticate()
         // authenticated!
         getData()
+        // getting data!
     }
 }
 //sampleEnd
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.6.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.6.kt
index 1bb59406e..a11aee1b6 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.6.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.6.kt
@@ -1,20 +1,12 @@
 fun main() {
-    //sampleStart
-    // Operand statically typed as floating-point number
-    println(Double.NaN == Double.NaN)                 // false
+//sampleStart
+    val x = 1
+    val xShiftedLeft = (x shl 2)
+    println(xShiftedLeft)  
+    // 4
     
-    // Operand NOT statically typed as floating-point number
-    // So NaN is equal to itself
-    println(listOf(Double.NaN) == listOf(Double.NaN)) // true
-
-    // Operand statically typed as floating-point number
-    println(0.0 == -0.0)                              // true
-    
-    // Operand NOT statically typed as floating-point number
-    // So -0.0 is less than 0.0
-    println(listOf(0.0) == listOf(-0.0))              // false
-
-    println(listOf(Double.NaN, Double.POSITIVE_INFINITY, 0.0, -0.0).sorted())
-    // [-0.0, 0.0, Infinity, NaN]
-    //sampleEnd
+    val xAnd = x and 0x000FF000
+    println(xAnd)          
+    // 0
+//sampleEnd
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.7.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.7.kt
new file mode 100644
index 000000000..1bb59406e
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/numbers/f56d9449111795feee96b7f922b3320d.7.kt
@@ -0,0 +1,20 @@
+fun main() {
+    //sampleStart
+    // Operand statically typed as floating-point number
+    println(Double.NaN == Double.NaN)                 // false
+    
+    // Operand NOT statically typed as floating-point number
+    // So NaN is equal to itself
+    println(listOf(Double.NaN) == listOf(Double.NaN)) // true
+
+    // Operand statically typed as floating-point number
+    println(0.0 == -0.0)                              // true
+    
+    // Operand NOT statically typed as floating-point number
+    // So -0.0 is less than 0.0
+    println(listOf(0.0) == listOf(-0.0))              // false
+
+    println(listOf(Double.NaN, Double.POSITIVE_INFINITY, 0.0, -0.0).sorted())
+    // [-0.0, 0.0, Infinity, NaN]
+    //sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.1.kt
index 8fbc81d87..4f795b358 100644
--- a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.1.kt
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.1.kt
@@ -1,28 +1,15 @@
-//sampleStart
-fun testString() {
-    var stringInput: String? = null
-    // stringInput is smart-cast to String type
-    stringInput = ""
-    try {
-        // The compiler knows that stringInput isn't null
-        println(stringInput.length)
-        // 0
+fun main() {
+    val input: Any = "Hello, Kotlin"
 
-        // The compiler rejects previous smart cast information for 
-        // stringInput. Now stringInput has the String? type.
-        stringInput = null
+    if (input is String) {
+        println("Message length: ${input.length}")
+        // Message length: 13
+    }
 
-        // Trigger an exception
-        if (2 > 1) throw Exception()
-        stringInput = ""
-    } catch (exception: Exception) {
-        // The compiler knows stringInput can be null
-        // so stringInput stays nullable.
-        println(stringInput?.length)
-        // null
+    if (input !is String) { // Same as !(input is String)
+        println("Input is not a valid message")
+    } else {
+        println("Processing message: ${input.length} characters")
+        // Processing message: 13 characters
     }
-}
-//sampleEnd
-fun main() {
-    testString()
 }
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.10.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.10.kt
new file mode 100644
index 000000000..f6f4271fc
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.10.kt
@@ -0,0 +1,21 @@
+interface Animal {
+    fun makeSound()
+}
+
+class Dog : Animal {
+    // Implements behavior for makeSound()
+    override fun makeSound() {
+        println("Dog says woof!")
+    }
+}
+
+fun printAnimalInfo(animal: Animal) {
+    animal.makeSound()
+}
+
+fun main() {
+    val dog = Dog()
+    // Upcasts Dog instance to Animal
+    printAnimalInfo(dog)  
+    // Dog says woof!
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.11.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.11.kt
new file mode 100644
index 000000000..3f9ce36c0
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.11.kt
@@ -0,0 +1,26 @@
+interface Animal {
+    fun makeSound()
+}
+
+class Dog : Animal {
+    override fun makeSound() {
+        println("Dog says woof!")
+    }
+
+    fun bark() {
+        println("BARK!")
+    }
+}
+
+fun main() {
+    // Creates animal as a Dog instance with Animal
+    // type
+    val animal: Animal = Dog()
+    
+    // Safely downcasts animal to Dog type
+    val dog: Dog? = animal as? Dog
+
+    // Uses a safe call to call bark() if dog isn't null
+    dog?.bark()
+    // "BARK!"
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.2.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.2.kt
new file mode 100644
index 000000000..d1417361c
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.2.kt
@@ -0,0 +1,49 @@
+interface Animal {
+    val name: String
+    fun speak()
+}
+
+class Dog(override val name: String) : Animal {
+    override fun speak() = println("$name says: Woof!")
+}
+
+class Cat(override val name: String) : Animal {
+    override fun speak() = println("$name says: Meow!")
+}
+//sampleStart
+fun handleAnimal(animal: Animal) {
+    println("Handling animal: ${animal.name}")
+    animal.speak()
+    
+    // Use is operator to check for subtypes
+    if (animal is Dog) {
+        println("Special care instructions: This is a dog.")
+    } else if (animal is Cat) {
+        println("Special care instructions: This is a cat.")
+    }
+}
+//sampleEnd
+fun main() {
+    val pets: List<Animal> = listOf(
+        Dog("Buddy"),
+        Cat("Whiskers"),
+        Dog("Rex")
+    )
+
+    for (pet in pets) {
+        handleAnimal(pet)
+        println("---")
+    }
+    // Handling animal: Buddy
+    // Buddy says: Woof!
+    // Special care instructions: This is a dog.
+    // ---
+    // Handling animal: Whiskers
+    // Whiskers says: Meow!
+    // Special care instructions: This is a cat.
+    // ---
+    // Handling animal: Rex
+    // Rex says: Woof!
+    // Special care instructions: This is a dog.
+    // ---
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.3.kt
new file mode 100644
index 000000000..330654a17
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.3.kt
@@ -0,0 +1,12 @@
+fun logMessage(data: Any) {
+    // data is automatically cast to String
+    if (data is String) {
+        println("Received text: ${data.length} characters")
+    }
+}
+
+fun main() {
+    logMessage("Server started")
+    // Received text: 14 characters
+    logMessage(404)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.4.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.4.kt
new file mode 100644
index 000000000..06d61a8e3
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.4.kt
@@ -0,0 +1,12 @@
+fun logMessage(data: Any) {
+    // data is automatically cast to String
+    if (data !is String) return
+
+    println("Received text: ${data.length} characters")
+}
+
+fun main() {
+    logMessage("User signed in")
+    // Received text: 14 characters
+    logMessage(true)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.5.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.5.kt
new file mode 100644
index 000000000..94736843f
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.5.kt
@@ -0,0 +1,19 @@
+fun processInput(data: Any) {
+    when (data) {
+        // data is automatically cast to Int
+        is Int -> println("Log: Assigned new ID ${data + 1}")
+        // data is automatically cast to String
+        is String -> println("Log: Received message \"$data\"")
+        // data is automatically cast to IntArray
+        is IntArray -> println("Log: Processed scores, total = ${data.sum()}")
+    }
+}
+
+fun main() {
+    processInput(1001)
+    // Log: Assigned new ID 1002
+    processInput("System rebooted")
+    // Log: Received message "System rebooted"
+    processInput(intArrayOf(10, 20, 30))
+    // Log: Processed scores, total = 60
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.6.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.6.kt
new file mode 100644
index 000000000..2814f2f53
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.6.kt
@@ -0,0 +1,37 @@
+sealed interface Status
+data class Ok(val currentRoom: String) : Status
+data object Error : Status
+
+class RobotVacuum(val rooms: List<String>) {
+    var index = 0
+
+    fun status(): Status =
+        if (index < rooms.size) Ok(rooms[index])
+        else Error
+
+    fun clean(): Status {
+        println("Finished cleaning ${rooms[index]}")
+        index++
+        return status()
+    }
+}
+
+fun main() {
+    //sampleStart
+    val robo = RobotVacuum(listOf("Living Room", "Kitchen", "Hallway"))
+
+    var status: Status = robo.status()
+    while (status is Ok) {
+        // The compiler smart casts status to OK type, so the currentRoom
+        // property is accessible.
+        println("Cleaning ${status.currentRoom}...")
+        status = robo.clean()
+    }
+    // Cleaning Living Room...
+    // Finished cleaning Living Room
+    // Cleaning Kitchen...
+    // Finished cleaning Kitchen
+    // Cleaning Hallway...
+    // Finished cleaning Hallway
+    //sampleEnd
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.7.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.7.kt
new file mode 100644
index 000000000..8fbc81d87
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.7.kt
@@ -0,0 +1,28 @@
+//sampleStart
+fun testString() {
+    var stringInput: String? = null
+    // stringInput is smart-cast to String type
+    stringInput = ""
+    try {
+        // The compiler knows that stringInput isn't null
+        println(stringInput.length)
+        // 0
+
+        // The compiler rejects previous smart cast information for 
+        // stringInput. Now stringInput has the String? type.
+        stringInput = null
+
+        // Trigger an exception
+        if (2 > 1) throw Exception()
+        stringInput = ""
+    } catch (exception: Exception) {
+        // The compiler knows stringInput can be null
+        // so stringInput stays nullable.
+        println(stringInput?.length)
+        // null
+    }
+}
+//sampleEnd
+fun main() {
+    testString()
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.8.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.8.kt
new file mode 100644
index 000000000..b2a4c9a6e
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.8.kt
@@ -0,0 +1,13 @@
+fun main() {
+    val rawInput: Any = "user-1234"
+
+    // Casts to String successfully
+    val userId = rawInput as? String
+    println("Logging in user with ID: $userId")
+    // Logging in user with ID: user-1234
+
+    // Assigns a null value to wrongCast
+    val wrongCast = rawInput as? Int
+    println("wrongCast contains: $wrongCast")
+    // wrongCast contains: null
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.9.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.9.kt
new file mode 100644
index 000000000..20c63a344
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/typecasts/2a72485ade1536976a77040176bcf3a1.9.kt
@@ -0,0 +1,27 @@
+fun main() {
+    val config: Map<String, Any?> = mapOf(
+        "username" to "kodee",
+        "alias" to null,
+        "loginAttempts" to 3
+    )
+
+    // Unsafely casts to a nullable String
+    val username: String? = config["username"] as String?
+    println("Username: $username")
+    // Username: kodee
+
+    // Unsafely casts a null value to a nullable String
+    val alias: String? = config["alias"] as String?
+    println("Alias: $alias")
+    // Alias: null
+
+    // Fails to cast to nullable String and throws ClassCastException
+    // val unsafeAttempts: String? = config["loginAttempts"] as String?
+    // println("Login attempts (unsafe): $unsafeAttempts")
+    // Exception in thread "main" java.lang.ClassCastException
+
+    // Fails to cast to nullable String and returns null
+    val safeAttempts: String? = config["loginAttempts"] as? String
+    println("Login attempts (safe): $safeAttempts")
+    // Login attempts (safe): null
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.1.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.1.kt
new file mode 100644
index 000000000..f0db73272
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.1.kt
@@ -0,0 +1,23 @@
+import kotlin.uuid.ExperimentalUuidApi
+import kotlin.uuid.Uuid
+
+@OptIn(ExperimentalUuidApi::class)
+fun main() {
+    val valid = Uuid.parseOrNull("550e8400-e29b-41d4-a716-446655440000")
+    println(valid)
+    // 550e8400-e29b-41d4-a716-446655440000
+
+    val invalid = Uuid.parseOrNull("not-a-uuid")
+    println(invalid)
+    // null
+
+
+    val hexDashValid = Uuid.parseHexDashOrNull("550e8400-e29b-41d4-a716-446655440000")
+    println(hexDashValid)
+    // 550e8400-e29b-41d4-a716-446655440000
+
+
+    val hexDashInvalid = Uuid.parseHexDashOrNull("550e8400e29b41d4a716446655440000")
+    println(hexDashInvalid)
+    // null
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.2.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.2.kt
new file mode 100644
index 000000000..2acaf4fb4
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.2.kt
@@ -0,0 +1,17 @@
+import kotlin.uuid.ExperimentalUuidApi
+import kotlin.uuid.Uuid
+
+@OptIn(ExperimentalUuidApi::class)
+fun main() {
+    // Generates a v4 UUID
+    val v4 = Uuid.generateV4()
+    println(v4)
+
+    // Generates a v7 UUID
+    val v7 = Uuid.generateV7()
+    println(v7)
+
+    // Generates a v4 UUID
+    val random = Uuid.random()
+    println(random)
+}
\ No newline at end of file
diff --git a/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.3.kt b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.3.kt
new file mode 100644
index 000000000..7cb622e1d
--- /dev/null
+++ b/src/test/resources/test-compile-data/jvm/kotlin-web-site/whatsnew23/0e71aba149e9509c275d31f17457ff45.3.kt
@@ -0,0 +1,13 @@
+import kotlin.uuid.ExperimentalUuidApi
+import kotlin.uuid.Uuid
+import kotlin.time.ExperimentalTime
+import kotlin.time.Instant
+
+@OptIn(ExperimentalUuidApi::class, ExperimentalTime::class)
+fun main() {
+    val timestamp = Instant.fromEpochMilliseconds(1577836800000) // 2020-01-01T00:00:00Z
+
+    // Generates a v7 UUID for the specified timestamp (without monotonicity guarantees)
+    val v7AtTimestamp = Uuid.generateV7NonMonotonicAt(timestamp)
+    println(v7AtTimestamp)
+}
\ No newline at end of file