[FE] Add missing 'ClassId' check in Kotlin class loading (KTIJ-23435)

'findKotlinClassOrContent()' does not really distinguish between
outer class names and package path components, so it might return
'foo/bar/Baz.Boo' for 'foo/bar/Baz/Boo'. Possibly because
 'findKotlinClassOrContent()' potentially returns a raw byte array,
 ClassId checking is supposed to be performed in
 'extractClassMetadata()'. For Java, it happens inside
 'FirJavaFacade.findClass()', yet for Kotlin the check was absent.

compiler/fir/fir2ir/tests-gen/org/jetbrains/kotlin/test/runners/codegen/FirBlackBoxCodegenTestGenerated.java

@@ -33763,6 +33763,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/package/packageLocalClassNotImportedWithDefaultImport.kt");
         }
 
+        @Test
+        @TestMetadata("packageOrNestedClass.kt")
+        public void testPackageOrNestedClass() throws Exception {
+            runTest("compiler/testData/codegen/box/package/packageOrNestedClass.kt");
+        }
+
         @Test
         @TestMetadata("packageQualifiedMethod.kt")
         public void testPackageQualifiedMethod() throws Exception {

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/deserialization/JvmClassFileBasedSymbolProvider.kt

@@ -108,15 +108,15 @@ class JvmClassFileBasedSymbolProvider(
                 // Nested class of Kotlin class should have been a Kotlin class.
                 return null
             }
-            val javaClass = javaFacade.findClass(classId, (result as? KotlinClassFinder.Result.ClassFileContent)?.content)
-                ?: return null
+            val knownContent = (result as? KotlinClassFinder.Result.ClassFileContent)?.content
+            val javaClass = javaFacade.findClass(classId, knownContent) ?: return null
             return ClassMetadataFindResult.NoMetadata { symbol ->
                 javaFacade.convertJavaClassToFir(symbol, classId.outerClassId?.let(::getClass), javaClass)
             }
         }
 
         val kotlinClass = result.kotlinJvmBinaryClass
-        if (kotlinClass.classHeader.kind != KotlinClassHeader.Kind.CLASS) return null
+        if (kotlinClass.classHeader.kind != KotlinClassHeader.Kind.CLASS || kotlinClass.classId != classId) return null
         val data = kotlinClass.classHeader.data ?: return null
         val strings = kotlinClass.classHeader.strings ?: return null
         val (nameResolver, classProto) = JvmProtoBufUtil.readClassDataFrom(data, strings)

compiler/testData/codegen/box/package/packageOrNestedClass.kt

@@ -0,0 +1,31 @@
+// TARGET_BACKEND: JVM_IR
+// FIR_IDENTICAL
+
+// MODULE: lib
+
+// FILE: lib.kt
+@file:Suppress("PACKAGE_OR_CLASSIFIER_REDECLARATION")
+package lib
+
+class foo {
+    class bar {
+        fun get(): Int = 1
+    }
+}
+
+// FILE: lib_foo.kt
+@file:Suppress("PACKAGE_OR_CLASSIFIER_REDECLARATION")
+package lib.foo
+
+class bar {
+    fun get(): Int = 0
+}
+
+// MODULE: main(lib)
+
+// FILE: test.kt
+
+fun box(): String {
+    val obj = lib.foo.bar()
+    return if (obj.get() == 0) "OK" else "ERROR"
+}

compiler/tests-common-new/tests-gen/org/jetbrains/kotlin/test/runners/codegen/IrBlackBoxCodegenTestGenerated.java

@@ -33763,6 +33763,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/package/packageLocalClassNotImportedWithDefaultImport.kt");
         }
 
+        @Test
+        @TestMetadata("packageOrNestedClass.kt")
+        public void testPackageOrNestedClass() throws Exception {
+            runTest("compiler/testData/codegen/box/package/packageOrNestedClass.kt");
+        }
+
         @Test
         @TestMetadata("packageQualifiedMethod.kt")
         public void testPackageQualifiedMethod() throws Exception {