Specify when the range is empty in KDoc

core/builtins/src/kotlin/Progressions.kt

@@ -41,7 +41,12 @@ public open class CharProgression
 
     override fun iterator(): CharIterator = CharProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /**
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =
@@ -98,7 +103,12 @@ public open class IntProgression
 
     override fun iterator(): IntIterator = IntProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /**
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =
@@ -155,7 +165,12 @@ public open class LongProgression
 
     override fun iterator(): LongIterator = LongProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /**
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =

core/builtins/src/kotlin/Range.kt

@@ -27,6 +27,8 @@ public interface ClosedRange<T: Comparable<T>> {
 
     /**
      * Checks whether the range is empty.
+
+     * The range is empty if its start value is greater than the end value.
      */
     public fun isEmpty(): Boolean = start > endInclusive
 }

core/builtins/src/kotlin/Ranges.kt

@@ -16,6 +16,11 @@ public class CharRange(start: Char, endInclusive: Char) : CharProgression(start,
 
     override fun contains(value: Char): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks whether the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =
@@ -42,6 +47,11 @@ public class IntRange(start: Int, endInclusive: Int) : IntProgression(start, end
 
     override fun contains(value: Int): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks whether the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =
@@ -68,6 +78,11 @@ public class LongRange(start: Long, endInclusive: Long) : LongProgression(start,
 
     override fun contains(value: Long): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks whether the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =

generators/builtins/progressions.kt

@@ -82,7 +82,12 @@ public open class $progression
 
     override fun iterator(): ${t}Iterator = ${t}ProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /**
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =

generators/builtins/ranges.kt

@@ -58,6 +58,11 @@ public class $range(start: $t, endInclusive: $t) : ${t}Progression(start, endInc
 
     override fun contains(value: $t): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks whether the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =

generators/builtins/unsignedTypes.kt

@@ -587,6 +587,11 @@ public class ${elementType}Range(start: $elementType, endInclusive: $elementType
 
     override fun contains(value: $elementType): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks if the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =
@@ -637,7 +642,12 @@ internal constructor(
 
     override fun iterator(): ${elementType}Iterator = ${elementType}ProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /** 
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =

libraries/stdlib/unsigned/src/kotlin/UIntRange.kt

@@ -22,6 +22,11 @@ public class UIntRange(start: UInt, endInclusive: UInt) : UIntProgression(start,
 
     override fun contains(value: UInt): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks if the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =
@@ -72,7 +77,12 @@ internal constructor(
 
     override fun iterator(): UIntIterator = UIntProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /** 
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =

libraries/stdlib/unsigned/src/kotlin/ULongRange.kt

@@ -22,6 +22,11 @@ public class ULongRange(start: ULong, endInclusive: ULong) : ULongProgression(st
 
     override fun contains(value: ULong): Boolean = first <= value && value <= last
 
+    /** 
+     * Checks if the range is empty.
+     
+     * The range is empty if its start value is greater than the end value.
+     */
     override fun isEmpty(): Boolean = first > last
 
     override fun equals(other: Any?): Boolean =
@@ -72,7 +77,12 @@ internal constructor(
 
     override fun iterator(): ULongIterator = ULongProgressionIterator(first, last, step)
 
-    /** Checks if the progression is empty. */
+    /** 
+     * Checks if the progression is empty.
+     
+     * Progression with a positive step is empty if its first element is greater than the last element.
+     * Progression with a negative step is empty if its first element is less than the last element.
+     */
     public open fun isEmpty(): Boolean = if (step > 0) first > last else first < last
 
     override fun equals(other: Any?): Boolean =