FIR IDE: fix collecting diagnostics for anonymous object declaration

idea/idea-frontend-fir/idea-fir-low-level-api/src/org/jetbrains/kotlin/idea/fir/low/level/api/util/utils.kt

@@ -14,9 +14,10 @@ import org.jetbrains.kotlin.fir.psi
 import org.jetbrains.kotlin.fir.render
 import org.jetbrains.kotlin.idea.caches.project.IdeaModuleInfo
 import org.jetbrains.kotlin.idea.util.getElementTextInContext
-import org.jetbrains.kotlin.psi.KtFile
 import org.jetbrains.kotlin.psi.KtDeclaration
 import org.jetbrains.kotlin.psi.KtElement
+import org.jetbrains.kotlin.psi.KtFile
+import org.jetbrains.kotlin.psi.KtObjectLiteralExpression
 import java.util.concurrent.TimeUnit
 import java.util.concurrent.locks.Lock
 
@@ -63,8 +64,10 @@ internal val FirDeclaration.ktDeclaration: KtDeclaration
     get() {
         val psi = psi
             ?: error("PSI element was not found for${render()}")
-        return psi as? KtDeclaration
-            ?: error(
+        return when (psi) {
+            is KtDeclaration -> psi
+            is KtObjectLiteralExpression -> psi.objectDeclaration
+            else -> error(
                 """
                    FirDeclaration.psi (${this::class.simpleName}) should be KtDeclaration but was ${psi::class.simpleName}
                    ${(psi as? KtElement)?.getElementTextInContext() ?: psi.text}
@@ -72,6 +75,7 @@ internal val FirDeclaration.ktDeclaration: KtDeclaration
                    ${render()}
                    """.trimIndent()
             )
+        }
     }
 
 internal val FirDeclaration.containingKtFileIfAny: KtFile?