replace 'trait' keyword with 'interface' in library code

libraries/stdlib/src/kotlin/collections/Sequence.kt

@@ -4,7 +4,7 @@ import java.util.Enumeration
 import java.util.NoSuchElementException
 
 deprecated("Use Sequence<T> instead.")
-public trait Stream<out T> {
+public interface Stream<out T> {
     /**
      * Returns an iterator that returns the values from the sequence.
      */
@@ -17,7 +17,7 @@ public trait Stream<out T> {
  *
  * @param T the type of elements in the sequence.
  */
-public trait Sequence<out T> : Stream<T>
+public interface Sequence<out T> : Stream<T>
 
 public fun<T> Stream<T>.toSequence(): Sequence<T> = object : Sequence<T> {
     override fun iterator(): Iterator<T> = this@toSequence.iterator()

libraries/stdlib/src/kotlin/io/Console.kt

@@ -126,7 +126,7 @@ public fun println() {
 
 // Since System.in can change its value on the course of program running,
 // we should always delegate to current value and cannot just pass it to InputStreamReader constructor.
-// We could use "by" implementation, but we can only use "by" with traits and InputStream is abstract class.
+// We could use "by" implementation, but we can only use "by" with interfaces and InputStream is abstract class.
 private val stdin: BufferedReader = BufferedReader(InputStreamReader(object : InputStream() {
     public override fun read(): Int {
         return System.`in`.read()

libraries/stdlib/src/kotlin/properties/Delegation.kt

@@ -1,13 +1,13 @@
 package kotlin.properties
 
 /**
- * Base trait that can be used for implementing property delegates of read-only properties. This is provided only for
- * convenience; you don't have to extend this trait as long as your property delegate has methods with the same
+ * Base interface that can be used for implementing property delegates of read-only properties. This is provided only for
+ * convenience; you don't have to extend this interface as long as your property delegate has methods with the same
  * signatures.
  * @param R the type of object which owns the delegated property.
  * @param T the type of the property value.
  */
-public trait ReadOnlyProperty<in R, out T> {
+public interface ReadOnlyProperty<in R, out T> {
     /**
      * Returns the value of the property for the given object.
      * @param thisRef the object for which the value is requested.
@@ -18,13 +18,13 @@ public trait ReadOnlyProperty<in R, out T> {
 }
 
 /**
- * Base trait that can be used for implementing property delegates of read-only properties. This is provided only for
- * convenience; you don't have to extend this trait as long as your property delegate has methods with the same
+ * Base interface that can be used for implementing property delegates of read-only properties. This is provided only for
+ * convenience; you don't have to extend this interface as long as your property delegate has methods with the same
  * signatures.
  * @param R the type of object which owns the delegated property.
  * @param T the type of the property value.
  */
-public trait ReadWriteProperty<in R, T> {
+public interface ReadWriteProperty<in R, T> {
     /**
      * Returns the value of the property for the given object.
      * @param thisRef the object for which the value is requested.

libraries/stdlib/src/kotlin/properties/Properties.kt

@@ -14,7 +14,7 @@ public class ChangeEvent(
 }
 
 deprecated("This class is part of an old, incomplete and suboptimal design of change notifications and is going to be removed")
-public trait ChangeListener {
+public interface ChangeListener {
     public fun onPropertyChange(event: ChangeEvent): Unit
 }
 

libraries/stdlib/src/kotlin/template/Templates.kt

@@ -86,8 +86,8 @@ public fun StringTemplate.toHtml(formatter: HtmlFormatter = HtmlFormatter()): St
  * how to format values for a particular [[Locale]] such as with the [[LocaleFormatter]] or
  * to escape particular characters in different output formats such as [[HtmlFormatter]
  */
-deprecated("This trait is part of an experimental implementation of string templates and is going to be removed")
-public trait Formatter {
+deprecated("This interface is part of an experimental implementation of string templates and is going to be removed")
+public interface Formatter {
     public fun format(buffer: Appendable, value: Any?): Unit
 }
 

libraries/stdlib/src/kotlin/test/Test.kt

@@ -92,7 +92,7 @@ public fun fails(block: () -> Unit): Throwable? {
  * Abstracts the logic for performing assertions. Specific implementations of [Asserter] can use JUnit
  * or TestNG assertion facilities.
  */
-public trait Asserter {
+public interface Asserter {
     /**
      * Asserts that the specified value is true.
      *

libraries/stdlib/src/kotlin/text/regex/Regex.kt

@@ -17,7 +17,7 @@
 package kotlin.text
 
 /** Represents a collection of captured groups in a single match. */
-public trait MatchGroupCollection : Collection<MatchGroup?> {
+public interface MatchGroupCollection : Collection<MatchGroup?> {
 
     /** Returns a group with the specified [index]
      *
@@ -34,7 +34,7 @@ public trait MatchGroupCollection : Collection<MatchGroup?> {
 /**
  * Represents the results from a single regular expression match.
  */
-public trait MatchResult {
+public interface MatchResult {
     /** The range of indices in the original string where match was captured. */
     public val range: IntRange
     /** The substring from the input string captured by this match. */

libraries/stdlib/src/kotlin/text/regex/RegexJVM.kt

@@ -19,7 +19,7 @@ package kotlin.text
 import java.util.regex.Pattern
 import java.util.regex.Matcher
 
-private trait FlagEnum {
+private interface FlagEnum {
     public val value: Int
     public val mask: Int
 }