[Compatibility] Restore old TargetPlatform and subtypes for compatibility

js/js.frontend/src/org/jetbrains/kotlin/js/resolve/JsPlatform.kt

@@ -0,0 +1,38 @@
+/*
+ * Copyright 2010-2015 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.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+@file:Suppress("DEPRECATION_ERROR")
+
+package org.jetbrains.kotlin.js.resolve
+
+import org.jetbrains.kotlin.platform.js.JsPlatforms
+import org.jetbrains.kotlin.resolve.TargetPlatform
+
+@Deprecated(
+    message = "This class is deprecated and will be removed soon, use API from 'org.jetbrains.kotlin.platform.*' packages instead",
+    replaceWith = ReplaceWith("JsPlatforms.defaultJsPlatform", "org.jetbrains.kotlin.platform.js.JsPlatforms"),
+    level = DeprecationLevel.ERROR
+)
+interface JsPlatform : TargetPlatform {
+    @JvmDefault
+    override val platformName: String
+        get() = "JS"
+
+    companion object {
+        @JvmField
+        val INSTANCE: JsPlatform = JsPlatforms.CompatJsPlatform
+    }
+}

js/js.frontend/src/org/jetbrains/kotlin/platform/js/JsPlatform.kt

@@ -14,8 +14,20 @@ abstract class JsPlatform : SimplePlatform("JS") {
         get() = "JavaScript "
 }
 
+@Suppress("DEPRECATION_ERROR")
 object JsPlatforms {
-    val defaultJsPlatform: TargetPlatform = object : JsPlatform() {}.toTargetPlatform()
+    private object DefaultSimpleJsPlatform : JsPlatform()
+
+    @Deprecated(
+        message = "Should be accessed only by compatibility layer, other clients should use 'defaultJsPlatform'",
+        level = DeprecationLevel.ERROR
+    )
+    object CompatJsPlatform : TargetPlatform(setOf(DefaultSimpleJsPlatform)),
+        // Needed for backward compatibility, because old code uses INSTANCEOF checks instead of calling extensions
+        org.jetbrains.kotlin.js.resolve.JsPlatform {}
+
+    val defaultJsPlatform: TargetPlatform
+        get() = CompatJsPlatform
 
     val allJsPlatforms: List<TargetPlatform> = listOf(defaultJsPlatform)
 }