Use correct class file version when copying anonymous objects in inliner

Generally, using state.classFileVersion would be enough because we
report an error when inlining bytecode into a class file with a lower
target version (see INLINE_FROM_HIGHER_PLATFORM). However, we take maxOf
with the original version of the class file, _just in case_ the user has
suppressed this error (for example, to workaround some other corner case
in the compiler).

 #KT-30744 Fixed

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/AnonymousObjectTransformer.kt

@@ -59,7 +59,7 @@ class AnonymousObjectTransformer(
 
         createClassReader().accept(object : ClassVisitor(Opcodes.API_VERSION, classBuilder.visitor) {
             override fun visit(version: Int, access: Int, name: String, signature: String?, superName: String, interfaces: Array<String>) {
-                classBuilder.defineClass(null, version, access, name, signature, superName, interfaces)
+                classBuilder.defineClass(null, maxOf(version, state.classFileVersion), access, name, signature, superName, interfaces)
                 if (languageVersionSettings.isCoroutineSuperClass(superName)) {
                     inliningContext.isContinuation = true
                 }

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/ObjectTransformer.kt

@@ -66,7 +66,7 @@ class WhenMappingTransformer(
         val fieldNode = transformationInfo.fieldNode
         classReader.accept(object : ClassVisitor(Opcodes.API_VERSION, classBuilder.visitor) {
             override fun visit(version: Int, access: Int, name: String, signature: String?, superName: String, interfaces: Array<String>) {
-                classBuilder.defineClass(null, version, access, name, signature, superName, interfaces)
+                classBuilder.defineClass(null, maxOf(version, state.classFileVersion), access, name, signature, superName, interfaces)
             }
 
             override fun visitField(access: Int, name: String, desc: String, signature: String?, value: Any?): FieldVisitor? {

compiler/backend/src/org/jetbrains/kotlin/codegen/inline/SamWrapperTransformer.kt

@@ -61,7 +61,7 @@ class SamWrapperTransformer(transformationInfo: SamWrapperTransformationInfo, pr
 
         classReader.accept(object : ClassVisitor(Opcodes.API_VERSION, classBuilder.visitor) {
             override fun visit(version: Int, access: Int, name: String, signature: String?, superName: String, interfaces: Array<String>) {
-                classBuilder.defineClass(null, version, access, name, signature, superName, interfaces)
+                classBuilder.defineClass(null, maxOf(version, state.classFileVersion), access, name, signature, superName, interfaces)
             }
 
         }, ClassReader.SKIP_FRAMES)
@@ -69,4 +69,4 @@ class SamWrapperTransformer(transformationInfo: SamWrapperTransformationInfo, pr
 
         return transformationResult
     }
-}
+}

compiler/testData/compileKotlinAgainstCustomBinaries/inlineAnonymousObjectWithDifferentTarget/library/A.java

@@ -0,0 +1,3 @@
+public interface A {
+    public static void method() {}
+}

compiler/testData/compileKotlinAgainstCustomBinaries/inlineAnonymousObjectWithDifferentTarget/library/foo.kt

@@ -0,0 +1,5 @@
+inline fun foo(crossinline x: () -> Unit): Any = object {
+    init {
+        x()
+    }
+}

compiler/testData/compileKotlinAgainstCustomBinaries/inlineAnonymousObjectWithDifferentTarget/output.txt

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

compiler/testData/compileKotlinAgainstCustomBinaries/inlineAnonymousObjectWithDifferentTarget/source.kt

@@ -0,0 +1,5 @@
+fun main() {
+    foo {
+        A.method()
+    }
+}

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

@@ -588,6 +588,14 @@ class CompileKotlinAgainstCustomBinariesTest : AbstractKotlinCompilerIntegration
         )
     }
 
+    fun testInlineAnonymousObjectWithDifferentTarget() {
+        val library = compileLibrary("library", additionalOptions = listOf("-jvm-target", "1.6"))
+        compileKotlin("source.kt", tmpdir, listOf(library), additionalOptions = listOf("-jvm-target", "1.8"))
+        val classLoader =
+            URLClassLoader(arrayOf(library.toURI().toURL(), tmpdir.toURI().toURL()), ForTestCompileRuntime.runtimeJarClassLoader())
+        classLoader.loadClass("SourceKt").getDeclaredMethod("main").invoke(null)
+    }
+
     companion object {
         // compiler before 1.1.4 version  did not include suspension marks into bytecode.
         private fun stripSuspensionMarksToImitateLegacyCompiler(bytes: ByteArray): Pair<ByteArray, Int> {