JVM_IR: add a test for when(enum) binary compatibility

compiler/testData/compileKotlinAgainstCustomBinaries/changedEnumsInLibrary/new/enum.kt

@@ -0,0 +1,4 @@
+package test
+
+enum class E1 { A, C, B, D }
+enum class E2 { A, B }

compiler/testData/compileKotlinAgainstCustomBinaries/changedEnumsInLibrary/old/enum.kt

@@ -0,0 +1,4 @@
+package test
+
+enum class E1 { A, B, C }
+enum class E2 { A, B, C }

compiler/testData/compileKotlinAgainstCustomBinaries/changedEnumsInLibrary/output.txt

@@ -0,0 +1 @@
+OK

compiler/testData/compileKotlinAgainstCustomBinaries/changedEnumsInLibrary/source.kt

@@ -0,0 +1,18 @@
+import test.*
+
+fun f1(x: E1) = when (x) {
+    E1.A -> "A"
+    E1.B -> "B"
+    E1.C -> "C"
+}
+
+fun f2(x: E2) = when (x) {
+    E2.A -> "A"
+    E2.B -> "B"
+    E2.C -> "C"
+}
+
+fun run(): String {
+    val c2 = try { f2(E2.C) } catch (e: java.lang.NoSuchFieldError) { "" }
+    return f1(E1.A) + f1(E1.B) + f1(E1.C) + f2(E2.A) + f2(E2.B) + c2
+}

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

@@ -519,6 +519,17 @@ class CompileKotlinAgainstCustomBinariesTest : AbstractKotlinCompilerIntegration
             .loadClass("SourceKt").getDeclaredMethod("run").invoke(null)
     }
 
+    fun testChangedEnumsInLibrary() {
+        val oldLibrary = compileLibrary("old", checkKotlinOutput = {})
+        val newLibrary = compileLibrary("new", checkKotlinOutput = {})
+        compileKotlin("source.kt", tmpdir, listOf(oldLibrary))
+
+        val result =
+            URLClassLoader(arrayOf(newLibrary.toURI().toURL(), tmpdir.toURI().toURL()), ForTestCompileRuntime.runtimeJarClassLoader())
+                .loadClass("SourceKt").getDeclaredMethod("run").invoke(null) as String
+        assertEquals("ABCAB", result)
+    }
+
     fun testClassFromJdkInLibrary() {
         val library = compileLibrary("library")
         compileKotlin("source.kt", tmpdir, listOf(library))