KT-62695 [AA] Refactor KDocReferenceResolver.findParentSymbol

Avoid traversing parents when there are none

analysis/analysis-api-fir/src/org/jetbrains/kotlin/analysis/api/fir/references/KDocReferenceResolver.kt

@@ -100,15 +100,27 @@ internal object KDocReferenceResolver {
     private fun findParentSymbol(symbol: KtSymbol, goBackSteps: Int, selectedFqName: FqName): KtSymbol? {
         if (symbol !is KtDeclarationSymbol && symbol !is KtPackageSymbol) return null
 
-        var currentSymbol = symbol as? KtDeclarationSymbol
-        repeat(goBackSteps) {
-            currentSymbol = currentSymbol?.getContainingSymbol() as? KtClassOrObjectSymbol
+        if (symbol is KtDeclarationSymbol) {
+            symbol.goToNthParent(goBackSteps)?.let { return it }
         }
-        currentSymbol?.let { return it }
 
         return getPackageSymbolIfPackageExists(selectedFqName)
     }
 
+    /**
+     * N.B. Works only for [KtClassOrObjectSymbol] parents chain.
+     */
+    context(KtAnalysisSession)
+    private fun KtDeclarationSymbol.goToNthParent(steps: Int): KtDeclarationSymbol? {
+        var currentSymbol = this
+
+        repeat(steps) {
+            currentSymbol = currentSymbol.getContainingSymbol() as? KtClassOrObjectSymbol ?: return null
+        }
+
+        return currentSymbol
+    }
+
     context(KtAnalysisSession)
     private fun resolveKdocFqName(fqName: FqName, contextElement: KtElement): Collection<ResolveResult> {
         getExtensionReceiverSymbolByThisQualifier(fqName, contextElement).ifNotEmpty { return this }