Fir2Ir: handle nested class references in type parameter bounds

compiler/fir/fir2ir/src/org/jetbrains/kotlin/fir/backend/Fir2IrClassifierStorage.kt

@@ -546,6 +546,10 @@ class Fir2IrClassifierStorage(
         val parentId = classId.outerClassId
         val parentClass = parentId?.let { session.symbolProvider.getClassLikeSymbolByClassId(it) }
         val irParent = declarationStorage.findIrParent(classId.packageFqName, parentClass?.toLookupTag(), firClassSymbol, firClass.origin)!!
+
+        // firClass may be referenced by some parent's type parameters as a bound. In that case, getIrClassSymbol will be called recursively.
+        getCachedIrClass(firClass)?.let { return it.symbol }
+
         val irClass = firClass.convertWithOffsets { startOffset, endOffset ->
             symbolTable.declareClass(signature, { symbol }) {
                 Fir2IrLazyClass(components, startOffset, endOffset, firClass.irOrigin(firProvider), firClass, symbol).apply {

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

@@ -7355,6 +7355,12 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
             runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClass.kt");
         }
 
+        @Test
+        @TestMetadata("nestedClassAsBound.kt")
+        public void testNestedClassAsBound() throws Exception {
+            runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt");
+        }
+
         @Test
         @TestMetadata("nestedClassInAnnotationArgument.kt")
         public void testNestedClassInAnnotationArgument() throws Exception {

compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt

@@ -0,0 +1,10 @@
+// MODULE: lib
+// FILE: Q.kt
+class Q<T : Q.S> {
+    open class S {
+        val ok = "OK"
+    }
+}
+// MODULE: main(lib)
+// FILE: box.kt
+fun box() = Q.S().ok

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

@@ -7241,6 +7241,12 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
             runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClass.kt");
         }
 
+        @Test
+        @TestMetadata("nestedClassAsBound.kt")
+        public void testNestedClassAsBound() throws Exception {
+            runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt");
+        }
+
         @Test
         @TestMetadata("nestedClassInAnnotationArgument.kt")
         public void testNestedClassInAnnotationArgument() throws Exception {

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

@@ -7355,6 +7355,12 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
             runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClass.kt");
         }
 
+        @Test
+        @TestMetadata("nestedClassAsBound.kt")
+        public void testNestedClassAsBound() throws Exception {
+            runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt");
+        }
+
         @Test
         @TestMetadata("nestedClassInAnnotationArgument.kt")
         public void testNestedClassInAnnotationArgument() throws Exception {

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

@@ -337,6 +337,12 @@ public class JvmIrAgainstOldBoxTestGenerated extends AbstractJvmIrAgainstOldBoxT
         runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClass.kt");
     }
 
+    @Test
+    @TestMetadata("nestedClassAsBound.kt")
+    public void testNestedClassAsBound() throws Exception {
+        runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt");
+    }
+
     @Test
     @TestMetadata("nestedClassInAnnotationArgument.kt")
     public void testNestedClassInAnnotationArgument() throws Exception {

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

@@ -337,6 +337,12 @@ public class JvmOldAgainstIrBoxTestGenerated extends AbstractJvmOldAgainstIrBoxT
         runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClass.kt");
     }
 
+    @Test
+    @TestMetadata("nestedClassAsBound.kt")
+    public void testNestedClassAsBound() throws Exception {
+        runTest("compiler/testData/codegen/box/compileKotlinAgainstKotlin/nestedClassAsBound.kt");
+    }
+
     @Test
     @TestMetadata("nestedClassInAnnotationArgument.kt")
     public void testNestedClassInAnnotationArgument() throws Exception {