Why does my stack track missing steps?

Question

There seems to be no step in my stack stack entry.

private void StartLoadingResources(DataService separateDataService) { ... batchResource.Resources.Add(key, new List<string>()); // batchResource.Resources is the Dictionary object involved ... } 

Why does the stack trace go straight from StartLoadingResources to Insert (the Add step is missing)?

 System.AggregateException: One or more errors occurred. ---> System.ArgumentException: An item with the same key has already been added. at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at MyApp.Importer.StartLoadingResources(DataService separateDataService) in ****\MyApp\MyApp\Importer.cs:line 313 at MyApp.Importer.<Execute>b__5() in ****\MyApp\MyApp\Importer.cs:line 142 at System.Threading.Tasks.Task.Execute() --- End of inner exception stack trace --- at System.Threading.Tasks.Task.Wait(Int32 millisecondsTimeout, CancellationToken cancellationToken) at System.Threading.Tasks.Task.Wait() at MyApp.Importer.Execute() in ****\MyApp\MyApp\Importer.cs:line 157 at MyApp.Program.Execute() in ****\MyApp\MyApp\Program.cs:line 252 at MyApp.Program.Main(String[] args) in ****\MyApp\MyApp\Program.cs:line 47 ---> (Inner Exception #0) System.ArgumentException: An item with the same key has already been added. at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add) at MyApp.Importer.StartLoadingResources(DataService separateDataService) in ****\MyApp\MyApp\Importer.cs:line 313 at MyApp.Importer.<Execute>b__5() in ****\MyApp\MyApp\Importer.cs:line 142 at System.Threading.Tasks.Task.Execute()<--- 

The code is compiled as "Debugging", and the "Optimize code" in the Build options is not disabled.

Answer 1

Add method Dictionary<TKey, TValue> just calls Insert , given that it is a 1-line method, the compiler simply introduced this method call, because it is so trivial, even if optimization is not enabled.