[FE] Add test for compiling against library with kotlin sealed classes and interfaces

#KT-20423
#KT-13495

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/library/A.kt

@@ -0,0 +1,3 @@
+package test
+
+interface IA : IBase

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/library/B.kt

@@ -0,0 +1,6 @@
+package test
+
+sealed class B : Base(), IBase {
+    class First : B()
+    class Second : B()
+}

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/library/Base.kt

@@ -0,0 +1,5 @@
+package test
+
+sealed interface IBase
+
+sealed class Base

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/library/C.kt

@@ -0,0 +1,5 @@
+package test
+
+enum class C : IBase {
+    SomeValue, AnotherValue
+}

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/library/D.kt

@@ -0,0 +1,3 @@
+package test
+
+object D : Base(), IBase

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/main.kt

@@ -0,0 +1,36 @@
+import test.*
+
+fun test_1(base: IBase) {
+    val x = when (base) {
+        is IA -> 1
+        is B -> 2
+        is C -> 3
+        is D -> 4
+    }
+}
+
+fun test_2(base: IBase) {
+    val x = when (base) {
+        is IA -> 1
+        is B.First -> 2
+        is B.Second -> 3
+        C.SomeValue -> 4
+        C.AnotherValue -> 5
+        D -> 6
+    }
+}
+
+fun test_3(base: Base) {
+    val x = when (base) {
+        is B -> 2
+        is D -> 4
+    }
+}
+
+fun test_4(base: Base) {
+    val x = when (base) {
+        is B.First -> 2
+        is B.Second -> 3
+        D -> 6
+    }
+}

compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/output.txt

@@ -0,0 +1,23 @@
+warning: ATTENTION!
+This build uses unsafe internal compiler arguments:
+
+-XXLanguage:+FreedomForSealedClasses
+-XXLanguage:+SealedInterfaces
+
+This mode is not recommended for production use,
+as no stability/compatibility guarantees are given on
+compiler or generated code. Use it at your own risk!
+
+compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/main.kt:4:9: warning: variable 'x' is never used
+    val x = when (base) {
+        ^
+compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/main.kt:13:9: warning: variable 'x' is never used
+    val x = when (base) {
+        ^
+compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/main.kt:24:9: warning: variable 'x' is never used
+    val x = when (base) {
+        ^
+compiler/testData/compileKotlinAgainstCustomBinaries/sealedClassesAndInterfaces/main.kt:31:9: warning: variable 'x' is never used
+    val x = when (base) {
+        ^
+OK

compiler/tests/org/jetbrains/kotlin/jvm/compiler/CompileKotlinAgainstCustomBinariesTest.kt

@@ -694,6 +694,12 @@ class CompileKotlinAgainstCustomBinariesTest : AbstractKotlinCompilerIntegration
         compileKotlin("source.kt", tmpdir, listOf(library), additionalOptions = listOf("-Xallow-jvm-ir-dependencies"))
     }
 
+    fun testSealedClassesAndInterfaces() {
+        val features = listOf("-XXLanguage:+FreedomForSealedClasses", "-XXLanguage:+SealedInterfaces")
+        val library = compileLibrary("library", additionalOptions = features, checkKotlinOutput = {})
+        compileKotlin("main.kt", tmpdir, listOf(library), additionalOptions = features)
+    }
+
     // If this test fails, then bootstrap compiler most likely should be advanced
     fun testPreReleaseFlagIsConsistentBetweenBootstrapAndCurrentCompiler() {
         val bootstrapCompiler = JarFile(PathUtil.kotlinPathsForCompiler.compilerPath)