Deprecate Char-to-Number conversions in stdlib (JVM and JS)

- Int.toChar was left non-deprecated because the replacement is not intrinsic yet.
- Number.toChar was left non-deprecated because otherwise the deprecation propagates to the override, Int.toChar.

KT-23451

libraries/stdlib/js-ir/builtins/Char.kt

@@ -41,18 +41,30 @@ constructor(code: UShort) : Comparable<Char> {
     public operator fun rangeTo(other: Char): CharRange = CharRange(this, other)
 
     /** Returns the value of this character as a `Byte`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code.toByte()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toByte(): Byte = value.toByte()
     /** Returns the value of this character as a `Char`. */
     public fun toChar(): Char = this
     /** Returns the value of this character as a `Short`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code.toShort()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toShort(): Short = value.toShort()
     /** Returns the value of this character as a `Int`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toInt(): Int = value
     /** Returns the value of this character as a `Long`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code.toLong()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toLong(): Long = value.toLong()
     /** Returns the value of this character as a `Float`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code.toFloat()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toFloat(): Float = value.toFloat()
     /** Returns the value of this character as a `Double`. */
+    @Deprecated("Conversion of Char to Number is deprecated. Use Char.code property instead.", ReplaceWith("this.code.toDouble()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public fun toDouble(): Double = value.toDouble()
 
     override fun equals(other: Any?): Boolean {

libraries/stdlib/js-ir/builtins/Primitives.kt

@@ -202,6 +202,8 @@ public class Byte private constructor() : Number(), Comparable<Byte> {
      * The least significant 8 bits of the resulting `Char` code are the same as the bits of this `Byte` value,
      * whereas the most significant 8 bits are filled with the sign bit of this value.
      */
+    @Deprecated("Direct conversion to Char is deprecated. Use toInt().toChar() or Char constructor instead.", ReplaceWith("this.toInt().toChar()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public override fun toChar(): Char
     /**
      * Converts this [Byte] value to [Short].
@@ -447,6 +449,7 @@ public class Short private constructor() : Number(), Comparable<Short> {
      * The resulting `Char` code is equal to this value reinterpreted as an unsigned number,
      * i.e. it has the same binary representation as this `Short`.
      */
+    @Deprecated("Direct conversion to Char is deprecated. Use toInt().toChar() or Char constructor instead.", ReplaceWith("this.toInt().toChar()"))
     public override fun toChar(): Char
     /** Returns this value. */
     public override fun toShort(): Short
@@ -966,6 +969,8 @@ public class Float private constructor() : Number(), Comparable<Float> {
      *
      * The resulting `Char` value is equal to `this.toInt().toChar()`.
      */
+    @Deprecated("Direct conversion to Char is deprecated. Use toInt().toChar() or Char constructor instead.", ReplaceWith("this.toInt().toChar()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public override fun toChar(): Char
     /**
      * Converts this [Float] value to [Short].
@@ -1210,6 +1215,8 @@ public class Double private constructor() : Number(), Comparable<Double> {
      *
      * The resulting `Char` value is equal to `this.toInt().toChar()`.
      */
+    @Deprecated("Direct conversion to Char is deprecated. Use toInt().toChar() or Char constructor instead.", ReplaceWith("this.toInt().toChar()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public override fun toChar(): Char
     /**
      * Converts this [Double] value to [Short].

libraries/stdlib/js-ir/runtime/long.kt

@@ -262,6 +262,8 @@ public class Long internal constructor(
     public fun inv(): Long = Long(low.inv(), high.inv())
 
     public override fun toByte(): Byte = low.toByte()
+    @Deprecated("Direct conversion to Char is deprecated. Use toInt().toChar() or Char constructor instead.", ReplaceWith("this.toInt().toChar()"))
+    @DeprecatedSinceKotlin(warningSince = "1.5")
     public override fun toChar(): Char = low.toChar()
     public override fun toShort(): Short = low.toShort()
     public override fun toInt(): Int = low

libraries/stdlib/js-ir/src/generated/_CharCategories.kt

@@ -19,7 +19,7 @@ private object Category {
         val toBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
         val fromBase64 = IntArray(128)
         for (i in toBase64.indices) {
-            fromBase64[toBase64[i].toInt()] = i
+            fromBase64[toBase64[i].code] = i
         }
         
         // rangeStartDiff.length = 1482
@@ -54,7 +54,7 @@ private fun categoryValueFrom(code: Int, ch: Int): Int {
  * Returns the Unicode general category of this character as an Int.
  */
 internal fun Char.getCategoryValue(): Int {
-    val ch = this.toInt()
+    val ch = this.code
 
     val index = binarySearchRange(Category.decodedRangeStart, ch)
     val start = Category.decodedRangeStart[index]
@@ -70,7 +70,7 @@ internal fun decodeVarLenBase64(base64: String, fromBase64: IntArray, resultLeng
     var int = 0
     var shift = 0
     for (char in base64) {
-        val sixBit = fromBase64[char.toInt()]
+        val sixBit = fromBase64[char.code]
         int = int or ((sixBit and 0x1f) shl shift)
         if (sixBit < 0x20) {
             result[index++] = int

libraries/stdlib/js-ir/src/generated/_DigitChars.kt

@@ -40,7 +40,7 @@ internal fun binarySearchRange(array: IntArray, needle: Int): Int {
  * Returns `true` if this character is a digit.
  */
 internal fun Char.isDigitImpl(): Boolean {
-    val ch = this.toInt()
+    val ch = this.code
     val index = binarySearchRange(Digit.rangeStart, ch)
     val high = Digit.rangeStart[index] + 9
     return ch <= high

libraries/stdlib/js-ir/src/generated/_LetterChars.kt

@@ -20,7 +20,7 @@ private object Letter {
         val toBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"
         val fromBase64 = IntArray(128)
         for (i in toBase64.indices) {
-            fromBase64[toBase64[i].toInt()] = i
+            fromBase64[toBase64[i].code] = i
         }
         
         // rangeStartDiff.length = 356
@@ -72,7 +72,7 @@ internal fun Char.isUpperCaseImpl(): Boolean {
  *   - `0` otherwise.
  */
 private fun Char.getLetterType(): Int {
-    val ch = this.toInt()
+    val ch = this.code
     val index = binarySearchRange(Letter.decodedRangeStart, ch)
 
     val rangeStart = Letter.decodedRangeStart[index]

libraries/stdlib/js-ir/src/generated/_TitlecaseMappings.kt

@@ -13,7 +13,7 @@ package kotlin.text
 // 4 ranges totally
 @OptIn(ExperimentalStdlibApi::class)
 internal fun Char.titlecaseCharImpl(): Char {
-    val code = this.toInt()
+    val code = this.code
     // Letters repeating <Lu, Lt, Ll> sequence and code of the Lt is a multiple of 3, e.g. <DŽ, Dž, dž>
     if (code in 0x01c4..0x01cc || code in 0x01f1..0x01f3) {
         return (3 * ((code + 1) / 3)).toChar()

libraries/stdlib/js-ir/src/generated/_WhitespaceChars.kt

@@ -15,7 +15,7 @@ package kotlin.text
  * Returns `true` if this character is a whitespace.
  */
 internal fun Char.isWhitespaceImpl(): Boolean {
-    val ch = this.toInt()
+    val ch = this.code
     return ch in 0x0009..0x000d
             || ch in 0x001c..0x0020
             || ch == 0x00a0