Introduce Kotlin language version 1.2

Wherein DEFAULT version is still 1.1, which means that version 1.2 should be configured manually

compiler/util/src/org/jetbrains/kotlin/config/ApiVersion.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2010-2016 JetBrains s.r.o.
+ * Copyright 2010-2017 JetBrains s.r.o.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -41,7 +41,10 @@ class ApiVersion private constructor(
         val KOTLIN_1_1 = createByLanguageVersion(LanguageVersion.KOTLIN_1_1)
 
         @JvmField
-        val LATEST: ApiVersion = createByLanguageVersion(LanguageVersion.LATEST)
+        val KOTLIN_1_2 = createByLanguageVersion(LanguageVersion.KOTLIN_1_2)
+
+        @JvmField
+        val LATEST_STABLE: ApiVersion = createByLanguageVersion(LanguageVersion.LATEST_STABLE)
 
         @JvmStatic
         fun createByLanguageVersion(version: LanguageVersion): ApiVersion = parse(version.versionString)!!

compiler/util/src/org/jetbrains/kotlin/config/LanguageVersionSettings.kt

@@ -79,13 +79,14 @@ enum class LanguageFeature(
 
 enum class LanguageVersion(val major: Int, val minor: Int) : DescriptionAware {
     KOTLIN_1_0(1, 0),
-    KOTLIN_1_1(1, 1);
+    KOTLIN_1_1(1, 1),
+    KOTLIN_1_2(1, 2);
 
     val versionString: String
         get() = "$major.$minor"
 
     override val description: String
-        get() = versionString
+        get() = if (this > LATEST_STABLE) "$versionString (EXPERIMENTAL)" else versionString
 
     override fun toString() = versionString
 
@@ -97,7 +98,7 @@ enum class LanguageVersion(val major: Int, val minor: Int) : DescriptionAware {
         fun fromFullVersionString(str: String) = str.split(".", "-").let { if (it.size >= 2) fromVersionString("${it[0]}.${it[1]}") else null }
 
         @JvmField
-        val LATEST = values().last()
+        val LATEST_STABLE = KOTLIN_1_1
     }
 }
 
@@ -158,6 +159,6 @@ class LanguageVersionSettingsImpl @JvmOverloads constructor(
 
     companion object {
         @JvmField
-        val DEFAULT = LanguageVersionSettingsImpl(LanguageVersion.LATEST, ApiVersion.LATEST)
+        val DEFAULT = LanguageVersionSettingsImpl(LanguageVersion.LATEST_STABLE, ApiVersion.LATEST_STABLE)
     }
 }