I think, the targets of the build Settings, if one is not set, is in the build of the project is set up under the Settings, if the targets set, with the targets of the build Settings, right, but the actual testing it may not seem like it, I under the targets of the build Settings in swift language version is unspecified, should be in the build of the project under the Settings of swift language is set up under the version 4.1, but the result is an error, you must specify a swift version