<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Here’s an early draft of the proposal. Please fire away with comments! By the way, how would the visibility in subclasses in the same file be handled?<div class=""><br class=""></div><div class=""><a href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md" class="">https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md</a></div><div class=""><br class=""></div><div class=""><h1 style="box-sizing: border-box; margin-right: 0px; margin-bottom: 16px; margin-left: 0px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255); margin-top: 0px !important;" class="">Type-based Private Access Level</h1><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box;" class="">Proposal: <a href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none;" class="">SE-XXXX</a></li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Authors: <a href="http://github.com/hartbit" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none;" class="">David Hart</a></li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Review Manager: TBD</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">Status: TBD</li></ul><h2 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-introduction" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#introduction" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Introduction</h2><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">This proposal extends the visibility of the <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> access level to all extensions, declarations and nested types in the same file.</p><h2 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-motivation" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#motivation" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Motivation</h2><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">Proposal <a href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/0025-scoped-access-level.md" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none;" class="">SE-0025</a> introduced a lexically-scoped access level named <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> and renamed the file-based access level to <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code>. The hope was for <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> to be a good default for restricting visibility further than the whole module and for <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code> to be used in rarer occasions when that restriction needed to be loosened.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">Unfortunately, that goal of the proposal has not been realized: Swift's reliance on extensions as a grouping and conformance mechanism has made <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code> more necessary than expected and has caused more friction between <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> and <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code> than intended.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">As a consequence, experience with using Swift 3 has caused mixed reactions from the mailing list and greater Swift community, culminating in proposal <a href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/0159-fix-private-access-levels.md" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none;" class="">SE-0159</a> which suggested reverting the access level changes. That proposal was rejected to continue supporting the code written since Swift 3 which benefits from the distinction between <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> and <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code>, but it was recognized that the language's lack of a good default access level more restictive than <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">internal</code> was unfortunate.</p><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">In the hopes of fulfilling the initial goal of <a href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/0025-scoped-access-level.md" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none;" class="">SE-0025</a>, this proposal defines the visibility of the <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> access level to extensions, declarations and nested types of the member's type in the same file to increase its usefulness and as a good default private access level. <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">fileprivate</code> then logically achieves its intended goal of being more rarely used and adheres to Swift's "progressive disclosure” philosophy.</p><h2 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-detailed-design" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#detailed-design" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Detailed design</h2><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">The design of this proposal defines the visibility of a <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">private</code> member declared within a type <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> or an extension of type <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> to:</p><ul style="box-sizing: border-box; padding-left: 2em; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class=""><li style="box-sizing: border-box;" class="">the declaration of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> if it occurs in the same file</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">all extensions of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> or subclasses of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> in the same file</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">all declarations of nested types of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> in the same file</li><li style="box-sizing: border-box; margin-top: 0.25em;" class="">all extensions of nested types of <code style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; padding: 0.2em 0px; margin: 0px; background-color: rgba(27, 31, 35, 0.0470588); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px;" class="">X</code> in the same file</li></ul><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">To illustrate the consequence of those rules, the following examples will be used with two files in the same module:</p><h3 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; font-size: 1.25em; line-height: 1.25; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-personswift" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#personswift" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Person.swift</h3><div class="highlight highlight-source-swift" style="box-sizing: border-box; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; word-wrap: normal; padding: 16px; overflow: auto; background-color: rgb(246, 248, 250); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-break: normal;" class=""><span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">struct</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Person</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">let</span> name<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span>
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">let</span> gender<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> Gender
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">private</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">let</span> age<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span>
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">var</span> greeting {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> <span class="pl-s" style="box-sizing: border-box; color: rgb(24, 54, 145);"><span class="pl-pds" style="box-sizing: border-box;">"</span>Hello, my name is <span class="pl-pse" style="box-sizing: border-box;">\(</span><span class="pl-s1" style="box-sizing: border-box; color: rgb(51, 51, 51);">name</span><span class="pl-pse" style="box-sizing: border-box;"><span class="pl-s1" style="box-sizing: border-box;">)</span></span><span class="pl-pds" style="box-sizing: border-box;">"</span></span>
}
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">init</span>(<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);"><span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">name</span></span>: <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span>, <span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);"><span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">gender</span></span>: Gender, <span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);"><span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">age</span></span>: <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span>) {
<span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">self</span>.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">name</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">=</span> name
<span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">self</span>.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">age</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">=</span> age
}
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">func</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">greet</span>() {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> age is accessible because it is defined in the same declaration but secreyAge is not because it is defined</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> in a nested type so the following piece of code would generate a compilation error:</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> if age < gender.secrecyAge {</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> instead:</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">if</span> Gender.<span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">shouldRevealAge</span>(<span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">self</span>) {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> fullGreeting is accessible because it is defined in an</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> extension of the same type in the same file</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">print</span>(fullGreeting)
} <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">else</span> {
<span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">print</span>(greeting)
}
}
}
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> private at the top-level scope continues to be equivalent to fileprivate</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span><span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">private</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">extension</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Person</span> {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> fullGreeting is implictly private due to the extension's modifier</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">var</span> fullGreeting<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span> {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> age is accessible because it is defined in the declaration of the extension's type in the same file</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> <span class="pl-s" style="box-sizing: border-box; color: rgb(24, 54, 145);"><span class="pl-pds" style="box-sizing: border-box;">"</span>Hello, my name is <span class="pl-pse" style="box-sizing: border-box;">\(</span><span class="pl-s1" style="box-sizing: border-box; color: rgb(51, 51, 51);">name</span><span class="pl-pse" style="box-sizing: border-box;"><span class="pl-s1" style="box-sizing: border-box;">)</span></span>, I'm <span class="pl-pse" style="box-sizing: border-box;">\(</span><span class="pl-s1" style="box-sizing: border-box; color: rgb(51, 51, 51);">age</span><span class="pl-pse" style="box-sizing: border-box;"><span class="pl-s1" style="box-sizing: border-box;">)</span></span> years old.<span class="pl-pds" style="box-sizing: border-box;">"</span></span>
}
}
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">extension</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Person</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">enum</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Gender</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">case</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">male</span>
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">case</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">female</span>
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">private</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">var</span> secrecyAge {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">switch</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">self</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">case</span> .<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">male</span><span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">60</span>
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">case</span> .<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">female</span><span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">50</span>
}
}
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">static</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">func</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">shouldRevealAge</span>(<span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">_</span> <span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">person</span>: Person) <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">-></span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">Bool</span> {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> age is accessible because we are in the declaration of a nested type that declared age</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> person.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">age</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);"><</span> person.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">gender</span>.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">secrecyAge</span>
}
}
}
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">extension</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Gender</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">static</span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">func</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">leakAge</span>(<span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">of</span> <span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">person</span>: Person) {
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> age is accessible because we are in the extension of a nested type in the same file</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> <span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> person.<span class="pl-smi" style="box-sizing: border-box; color: rgb(51, 51, 51);">age</span>
}
}</pre></div><h3 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; font-size: 1.25em; line-height: 1.25; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-otherswift" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#otherswift" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Other.swift</h3><div class="highlight highlight-source-swift" style="box-sizing: border-box; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);"><pre style="box-sizing: border-box; font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, Courier, monospace; font-size: 13.600000381469727px; margin-top: 0px; margin-bottom: 0px; line-height: 1.45; word-wrap: normal; padding: 16px; overflow: auto; background-color: rgb(246, 248, 250); border-top-left-radius: 3px; border-top-right-radius: 3px; border-bottom-right-radius: 3px; border-bottom-left-radius: 3px; word-break: normal;" class=""><span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">extension</span> <span class="pl-en" style="box-sizing: border-box; color: rgb(121, 93, 163);">Person</span> : <span class="pl-e" style="box-sizing: border-box; color: rgb(121, 93, 163);"><span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">CustomStringConvertible</span> </span>{
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">var</span> desription<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">:</span> <span class="pl-c1" style="box-sizing: border-box; color: rgb(0, 134, 179);">String</span> {
<span class="pl-k" style="box-sizing: border-box; color: rgb(167, 29, 93);">return</span> fullGreeting
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"><span class="pl-c" style="box-sizing: border-box;">//</span> error: fullGreeting is not available because it is defined in another file</span>
<span class="pl-c" style="box-sizing: border-box; color: rgb(150, 152, 150);"></span> }
}</pre></div><h2 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-source-compatibility" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#source-compatibility" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Source compatibility</h2><p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 16px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255);" class="">Incoming...</p><h2 style="box-sizing: border-box; margin-top: 24px; margin-bottom: 16px; line-height: 1.25; padding-bottom: 0.3em; border-bottom-width: 1px; border-bottom-style: solid; border-bottom-color: rgb(234, 236, 239); color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; background-color: rgb(255, 255, 255);" class=""><a id="user-content-alternatives-considered" class="anchor" href="https://github.com/hartbit/swift-evolution/blob/type-private/proposals/XXXX-typed-based-private.md#alternatives-considered" aria-hidden="true" style="box-sizing: border-box; background-color: transparent; -webkit-text-decoration-skip: objects; color: rgb(3, 102, 214); text-decoration: none; float: left; padding-right: 4px; margin-left: -20px; line-height: 1;"><svg aria-hidden="true" class="octicon octicon-link" height="16" version="1.1" viewBox="0 0 16 16" width="16"><path fill-rule="evenodd" d="M4 9h1v1H4c-1.5 0-3-1.69-3-3.5S2.55 3 4 3h4c1.45 0 3 1.69 3 3.5 0 1.41-.91 2.72-2 3.25V8.59c.58-.45 1-1.27 1-2.09C10 5.22 8.98 4 8 4H4c-.98 0-2 1.22-2 2.5S3 9 4 9zm9-3h-1v1h1c1 0 2 1.22 2 2.5S13.98 12 13 12H9c-.98 0-2-1.22-2-2.5 0-.83.42-1.64 1-2.09V6.25c-1.09.53-2 1.84-2 3.25C6 11.31 7.55 13 9 13h4c1.45 0 3-1.69 3-3.5S14.5 6 13 6z"></path></svg></a>Alternatives Considered</h2><div style="box-sizing: border-box; margin-top: 0px; color: rgb(36, 41, 46); font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji', 'Segoe UI Symbol'; font-size: 16px; background-color: rgb(255, 255, 255); margin-bottom: 0px !important;" class="">Incoming...</div></div><div class=""><br class=""><div><blockquote type="cite" class=""><div class="">On 3 Apr 2017, at 20:34, Douglas Gregor via swift-evolution <<a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a>> wrote:</div><br class="Apple-interchange-newline"><div class=""><meta http-equiv="Content-Type" content="text/html charset=utf-8" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Hello Swift Community,<div class=""><br class=""></div><div class="">In rejecting <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0159-fix-private-access-levels.md" class="">SE-0159</a>, the core team described a potential direction we would like to investigate for “private” access control that admits a limited form of type-based access control within files. The core team is seeking some discussion here and a motivated volunteer to put together a proposal along these lines for review in the Swift 4 time-frame (i.e., very soon). To be clear, the core team it’s sure this is the right direction to go… but it appears promising and we would *love* to be able to settle the access-control issue.</div><div class=""><br class=""></div><div class="">The design, specifically, is that a “private” member declared within a type “X” or an extension thereof would be accessible from:</div><div class=""><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* An extension of “X” in the same file</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* The definition of “X”, if it occurs in the same file</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>* A nested type (or extension thereof) of one of the above that occurs in the same file</div><div class=""><br class=""></div><div class="">This design has a number of apparent benefits:</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ “private” becomes the right default for “less than whole module” visibility, and aligns well with Swift coding style that divides a type’s definition into a number of extensions.</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ “fileprivate” remains for existing use cases, but now it’s use it more rare, which has several advantages:</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ It fits well with the "progressive disclosure” philosophy behind Swift: you can use public/internal/private for a while before encountering and having to learn about “fileprivate” (note: we thought this was going to be true of <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0025-scoped-access-level.md" class="">SE-0025</a>, but we were clearly wrong)</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ When “fileprivate” occurs, it means there’s some interesting coupling between different types in the same file. That makes fileprivate a useful alert to the reader rather than, potentially, something that we routinely use and overlook so that we can separate implementations into extensions.</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ “private” is more closely aligned with other programming languages that use type-based access control, which can help programmers just coming to Swift. When they reach for “private”, they’re likely to get something similar to what they expect—with a little Swift twist due to Swift’s heavy use of extensions.</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>+ Loosening the access restrictions on “private” is unlikely to break existing code.</div><div class=""><br class=""></div><div class="">There are likely some drawbacks:</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>- Developers using patterns that depend on the existing lexically-scoped access control of “private” may find this new interpretation of “private” to be insufficiently strict</div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>- Swift’s access control would go from “entirely lexical” to “partly lexical and partly type-based”, which can be viewed as being more complicated</div><div class=""><br class=""></div></div><div class="">Thoughts? Volunteer?</div><div class=""><br class=""></div><div class=""><span class="Apple-tab-span" style="white-space: pre;"> </span>- Doug</div></div>_______________________________________________<br class="">swift-evolution mailing list<br class=""><a href="mailto:swift-evolution@swift.org" class="">swift-evolution@swift.org</a><br class="">https://lists.swift.org/mailman/listinfo/swift-evolution<br class=""></div></blockquote></div><br class=""></div></body></html>