[SLC] Fix nested classes missing in SLC structure tests for libraries

^KT-62038 fixed

analysis/symbol-light-classes/testData/structure/NestedClasses.lib.txt

@@ -0,0 +1,145 @@
+B.class:
+  KtClass:
+    line: 5
+    name: NestedInB
+    qualifier: B.NestedInB
+    light: KtLightClassForDecompiledDeclaration
+      name: NestedInB
+      qualifier: B.NestedInB
+      superTypes: [
+        PsiType:NestedInNestedInA
+      ]
+      superClass: KtLightClassForDecompiledDeclaration: NestedInNestedInA (A.NestedInA.NestedInNestedInA)
+      interfaces: []
+      supers: [
+        KtLightClassForDecompiledDeclaration: NestedInNestedInA (A.NestedInA.NestedInNestedInA)
+      ]
+
+  KtClass:
+    line: 8
+    name: InnerInB
+    qualifier: B.InnerInB
+    light: KtLightClassForDecompiledDeclaration
+      name: InnerInB
+      qualifier: B.InnerInB
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 4
+    name: B
+    qualifier: B
+    light: KtLightClassForDecompiledDeclaration
+      name: B
+      qualifier: B
+      superTypes: [
+        PsiType:A
+      ]
+      superClass: KtLightClassForDecompiledDeclaration: A (A)
+      interfaces: []
+      supers: [
+        KtLightClassForDecompiledDeclaration: A (A)
+      ]
+
+A.class:
+  KtClass:
+    line: 6
+    name: NestedInNestedInA
+    qualifier: A.NestedInA.NestedInNestedInA
+    light: KtLightClassForDecompiledDeclaration
+      name: NestedInNestedInA
+      qualifier: A.NestedInA.NestedInNestedInA
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 9
+    name: InnerInNestedInA
+    qualifier: A.NestedInA.InnerInNestedInA
+    light: KtLightClassForDecompiledDeclaration
+      name: InnerInNestedInA
+      qualifier: A.NestedInA.InnerInNestedInA
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 5
+    name: NestedInA
+    qualifier: A.NestedInA
+    light: KtLightClassForDecompiledDeclaration
+      name: NestedInA
+      qualifier: A.NestedInA
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 14
+    name: InnerInInnerInA
+    qualifier: A.InnerInA.InnerInInnerInA
+    light: KtLightClassForDecompiledDeclaration
+      name: InnerInInnerInA
+      qualifier: A.InnerInA.InnerInInnerInA
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 13
+    name: InnerInA
+    qualifier: A.InnerInA
+    light: KtLightClassForDecompiledDeclaration
+      name: InnerInA
+      qualifier: A.InnerInA
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]
+
+  KtClass:
+    line: 4
+    name: A
+    qualifier: A
+    light: KtLightClassForDecompiledDeclaration
+      name: A
+      qualifier: A
+      superTypes: [
+        PsiType:Object
+      ]
+      superClass: ClsClassImpl: Object (java.lang.Object)
+      interfaces: []
+      supers: [
+        ClsClassImpl: Object (java.lang.Object)
+      ]

analysis/symbol-light-classes/tests/org/jetbrains/kotlin/light/classes/symbol/base/AbstractSymbolLightClassesStructureTestBase.kt

@@ -12,7 +12,6 @@ import com.intellij.psi.search.GlobalSearchScope
 import org.jetbrains.kotlin.analysis.test.framework.test.configurators.AnalysisApiTestConfigurator
 import org.jetbrains.kotlin.analysis.utils.printer.PrettyPrinter
 import org.jetbrains.kotlin.asJava.toLightClass
-import org.jetbrains.kotlin.psi.KtClass
 import org.jetbrains.kotlin.psi.KtClassOrObject
 import org.jetbrains.kotlin.psi.KtEnumEntry
 import org.jetbrains.kotlin.psi.KtFile
@@ -101,24 +100,14 @@ open class AbstractSymbolLightClassesStructureTestBase(
     }.toSet()
 
     private fun wrongInheritorStructure(line: String): Nothing = error("Can't parse '$line' line correctly")
+
     protected fun PrettyPrinter.handleFile(ktFile: KtFile) {
         val text = ktFile.text
         if (ktFile.isCompiled) {
-            ktFile.declarations.forEach { classOrObject ->
-                if (classOrObject is KtClassOrObject) {
-                    if (classOrObject is KtClass && classOrObject.isEnum()) {
-                        classOrObject.declarations.forEach { declaration ->
-                            if (declaration is KtEnumEntry) {
-                                handleClassDeclaration(declaration, text)
-                                appendLine()
-                            }
-                        }
-                    }
-
-                    handleClassDeclaration(classOrObject, text)
-                    appendLine()
-                }
-            }
+            // A compiled file for a class should only contain a single class declaration. `*Kt.class` files on the other hand may contain
+            // top-level callables and need to be skipped.
+            val classOrObject = ktFile.declarations.singleOrNull() as? KtClassOrObject ?: return
+            handleCompiledClassDeclaration(classOrObject, text)
         } else {
             ktFile.forEachDescendantOfType<KtClassOrObject> { classOrObject ->
                 handleClassDeclaration(classOrObject, text)
@@ -127,6 +116,26 @@ open class AbstractSymbolLightClassesStructureTestBase(
         }
     }
 
+    /**
+     * [handleCompiledClassDeclaration] uses a custom traversal instead of [forEachDescendantOfType] because trying to access the PSI of
+     * compiled code in this test results in exceptions. Hence, we have to traverse nested classes and enum entries manually.
+     */
+    private fun PrettyPrinter.handleCompiledClassDeclaration(classOrObject: KtClassOrObject, text: String) {
+        classOrObject.declarations.forEach { declaration ->
+            when (declaration) {
+                is KtEnumEntry -> {
+                    // We don't call `handleCompiledClassDeclaration` to avoid printing class declarations inside enum entry initializers.
+                    handleClassDeclaration(declaration, text)
+                    appendLine()
+                }
+                is KtClassOrObject -> handleCompiledClassDeclaration(declaration, text)
+            }
+        }
+
+        handleClassDeclaration(classOrObject, text)
+        appendLine()
+    }
+
     private fun PrettyPrinter.handleClassDeclaration(declaration: KtClassOrObject, fileText: String) {
         appendLine("${declaration::class.simpleName}:")
         withIndent {