FIR: load parents of Java inner classes first, as before

compiler/fir/fir-deserialization/src/org/jetbrains/kotlin/fir/deserialization/AbstractFirDeserializedSymbolsProvider.kt

@@ -185,13 +185,27 @@ abstract class AbstractFirDeserializedSymbolsProvider(
         return packagePartsCache.getValue(packageFqName)
     }
 
+    protected open fun shouldLoadParentsFirst(classId: ClassId): Boolean = false
+
     protected open fun getClass(
         classId: ClassId,
         parentContext: FirDeserializationContext? = null
     ): FirRegularClassSymbol? {
+        if (parentContext == null && shouldLoadParentsFirst(classId)) {
+            return getClassAfterLoadingParents(classId)
+        }
         return classCache.getValue(classId, parentContext)
     }
 
+    private fun getClassAfterLoadingParents(classId: ClassId): FirRegularClassSymbol? {
+        classId.outerClassId?.let { parentClassId ->
+            val alreadyLoaded = classCache.getValueIfComputed(classId)
+            if (alreadyLoaded != null) return alreadyLoaded
+            getClassAfterLoadingParents(parentClassId)
+        }
+        return classCache.getValue(classId, null)
+    }
+
     private fun getTypeAlias(
         classId: ClassId,
     ): FirTypeAliasSymbol? {

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

@@ -22946,6 +22946,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/javaInterop/genericSamSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("javaOuterClassDependsOnInner.kt")
+        public void testJavaOuterClassDependsOnInner() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/javaOuterClassDependsOnInner.kt");
+        }
+
         @Test
         @TestMetadata("kt43217.kt")
         public void testKt43217() throws Exception {

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

@@ -93,6 +93,9 @@ open class KotlinDeserializedJvmSymbolsProvider(
     private val KotlinJvmBinaryClass.isPreReleaseInvisible: Boolean
         get() = classHeader.isPreRelease
 
+    override fun shouldLoadParentsFirst(classId: ClassId): Boolean =
+        javaSymbolProvider.hasTopLevelClassOf(classId)
+
     override fun extractClassMetadata(classId: ClassId, parentContext: FirDeserializationContext?): ClassMetadataFindResult? {
         if (knownNameInPackageCache.hasNoTopLevelClassOf(classId)) return null
         val result = try {

compiler/testData/codegen/box/javaInterop/javaOuterClassDependsOnInner.kt

@@ -0,0 +1,21 @@
+// TARGET_BACKEND: JVM
+// This is really a frontend test that checks loading of compiled Java classes.
+// MODULE: lib
+// FILE: I.java
+public interface I<T> {}
+
+// FILE: J.java
+public class J implements I<J.X> {
+    public static class X {}
+}
+
+// FILE: Z.java
+public class Z<T> {
+    public T foo(J.X x) { return null; }
+}
+
+// MODULE: main(lib)
+// FILE: main.kt
+class C : Z<Int>()
+
+fun box() = C().foo(null) ?: "OK"

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

@@ -22814,6 +22814,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/javaInterop/genericSamSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("javaOuterClassDependsOnInner.kt")
+        public void testJavaOuterClassDependsOnInner() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/javaOuterClassDependsOnInner.kt");
+        }
+
         @Test
         @TestMetadata("kt43217.kt")
         public void testKt43217() throws Exception {

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

@@ -22946,6 +22946,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/javaInterop/genericSamSmartcast.kt");
         }
 
+        @Test
+        @TestMetadata("javaOuterClassDependsOnInner.kt")
+        public void testJavaOuterClassDependsOnInner() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/javaOuterClassDependsOnInner.kt");
+        }
+
         @Test
         @TestMetadata("kt43217.kt")
         public void testKt43217() throws Exception {

compiler/tests-gen/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -19136,6 +19136,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
             runTest("compiler/testData/codegen/box/javaInterop/genericSamSmartcast.kt");
         }
 
+        @TestMetadata("javaOuterClassDependsOnInner.kt")
+        public void testJavaOuterClassDependsOnInner() throws Exception {
+            runTest("compiler/testData/codegen/box/javaInterop/javaOuterClassDependsOnInner.kt");
+        }
+
         @TestMetadata("kt43217.kt")
         public void testKt43217() throws Exception {
             runTest("compiler/testData/codegen/box/javaInterop/kt43217.kt");