FIR: distinguish lazy/non-lazy nested scopes more clear

compiler/fir/java/src/org/jetbrains/kotlin/fir/java/JavaSymbolProvider.kt

@@ -28,9 +28,7 @@ import org.jetbrains.kotlin.fir.java.scopes.JavaClassUseSiteMemberScope
 import org.jetbrains.kotlin.fir.java.scopes.JavaOverrideChecker
 import org.jetbrains.kotlin.fir.resolve.*
 import org.jetbrains.kotlin.fir.scopes.FirScope
-import org.jetbrains.kotlin.fir.scopes.impl.FirSuperTypeScope
-import org.jetbrains.kotlin.fir.scopes.impl.declaredMemberScope
-import org.jetbrains.kotlin.fir.scopes.impl.nestedClassifierScope
+import org.jetbrains.kotlin.fir.scopes.impl.*
 import org.jetbrains.kotlin.fir.symbols.CallableId
 import org.jetbrains.kotlin.fir.symbols.impl.*
 import org.jetbrains.kotlin.fir.toFirSourceElement
@@ -69,9 +67,8 @@ class JavaSymbolProvider(
         val symbol = this.getClassLikeSymbolByFqName(classId) ?: return null
         val regularClass = symbol.fir
         return if (regularClass is FirJavaClass) {
-            nestedClassifierScope(
+            lazyNestedClassifierScope(
                 classId,
-                session,
                 existingNames = regularClass.existingNestedClassifierNames,
                 symbolProvider = this
             )
@@ -110,12 +107,11 @@ class JavaSymbolProvider(
         visitedSymbols: MutableSet<FirClassLikeSymbol<*>>
     ): JavaClassUseSiteMemberScope {
         return scopeSession.getOrBuild(regularClass.symbol, JAVA_USE_SITE) {
-            val declaredScope = declaredMemberScope(
+            val declaredScope = if (regularClass is FirJavaClass) declaredMemberScopeWithLazyNestedScope(
                 regularClass,
-                useLazyNestedClassifierScope = regularClass is FirJavaClass,
-                existingNames = (regularClass as? FirJavaClass)?.existingNestedClassifierNames,
+                existingNames = regularClass.existingNestedClassifierNames,
                 symbolProvider = this
-            )
+            ) else declaredMemberScope(regularClass)
             val wrappedDeclaredScope = wrapScopeWithJvmMapped(regularClass, declaredScope, useSiteSession, scopeSession)
             val superTypeEnhancementScopes =
                 lookupSuperTypes(regularClass, lookupInterfaces = true, deep = false, useSiteSession = useSiteSession)