System.Reflection.RtFieldInfo.GetOneTimeFlags C# (CSharp) Method

        private void GetOneTimeFlags() 
        {
            Type declaringType = DeclaringType;

            // first take care of all the NO_INVOKE cases
            if (declaringType != null && declaringType.ContainsGenericParameters) 
            {
                m_invocationFlags |= INVOCATION_FLAGS_NO_INVOKE;
            }
            else if (Module.Assembly.GetType() == typeof(AssemblyBuilder)) 
            {
                AssemblyBuilder ab = Module.Assembly as AssemblyBuilder;
                if (ab.m_assemblyData.m_access == AssemblyBuilderAccess.Save)
                    m_invocationFlags |= INVOCATION_FLAGS_NO_INVOKE;
            }
            if ((declaringType == null && Module.Assembly.ReflectionOnly) || declaringType is ReflectionOnlyType)
            {
                m_invocationFlags |= INVOCATION_FLAGS_NO_INVOKE;
            }
            
            
            // this should be an usable field, determine the other flags 
            else 
            {
                if ((m_fieldAttributes & FieldAttributes.InitOnly) !=(FieldAttributes)0) 
                    m_invocationFlags |= INVOCATION_FLAGS_SPECIAL_FIELD;

                if ((m_fieldAttributes & FieldAttributes.HasFieldRVA) !=(FieldAttributes)0) 
                    m_invocationFlags |= INVOCATION_FLAGS_SPECIAL_FIELD;

                if (((m_fieldAttributes & FieldAttributes.FieldAccessMask) != FieldAttributes.Public) || (declaringType != null && !declaringType.IsVisible)) 
                    m_invocationFlags |= INVOCATION_FLAGS_NEED_SECURITY;

                // find out if the field type is one of the following: Primitive, Enum or Pointer
                Type fieldType = FieldType;
                if (fieldType.IsPointer || fieldType.IsEnum || fieldType.IsPrimitive) 
                    m_invocationFlags |= INVOCATION_FLAGS_FIELD_SPECIAL_CAST;
            }

            // must be last to avoid threading problems
            m_invocationFlags |= INVOCATION_FLAGS_INITIALIZED;
        }