Getting instances of generic types through the ApplicationManager is slow when the debugger is attached

[abeham]

On my machine with the VS debugger attached, it takes roughly two minutes for the call to e.g. ApplicationManager.Manager.GetInstances<HeuristicOptimizationProblem<IEvaluator, ISolutionCreator>>() to complete (it should be equally slow for any generic type).

The performance issue seems to be in LightweightApplicationManager.CheckTypeCompatibility(Type type, Type other) as well as in the SandboxApplicationManager:

if (type.IsGenericType && other.IsGenericType) {
  try {
    if (type.IsAssignableFrom(other.GetGenericTypeDefinition().MakeGenericType(type.GetGenericArguments())))
      return true;
  } catch (Exception) { }
}

Without debugger attached there is no noticeable performance penalty. What is the reason for this rather steep drop in performance?