fallback to SwiftASTContext for unsupported cases

Author: kastiglione

lldb/source/Plugins/TypeSystem/Swift/TypeSystemSwiftTypeRef.cpp

@@ -2077,10 +2077,14 @@ TypeSystemSwiftTypeRef::GetNumChildren(opaque_compiler_type_t type,
     // TODO: which of these should be logged on failure?
     if (auto *exe_scope = exe_ctx->GetBestExecutionContextScope())
       if (auto *runtime =
-              SwiftLanguageRuntime::Get(exe_scope->CalculateProcess()))
+              SwiftLanguageRuntime::Get(exe_scope->CalculateProcess())) {
         if (auto num_children =
                 runtime->GetNumChildren(GetCanonicalType(type), nullptr))
           return *num_children;
+        else
+          return m_swift_ast_context->GetNumChildren(
+              ReconstructType(type), omit_empty_base_classes, exe_ctx);
+      }
 
     return 0;
   };