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.send { color:#77bb77; }
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.error { color:#AA0000; }</style></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div class="bloop_markdown"><p>We’re running out of time, and there is still no feedback although Chris Lattner said to consider this topic in his thread: <a href="https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20160620/021793.html">Partial list of open Swift 3 design topics</a></p>
<ul>
<li>I’m not sure if we’re allowed to PR even if there is no feedback at all.</li>
<li><strong>Again this is a breaking change!</strong></li>
</ul>
<p></p></div><div class="bloop_original_html"><style>body{font-family:Helvetica,Arial;font-size:13px}</style><div id="bloop_customfont" style="font-family:Helvetica,Arial;font-size:13px; color: rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br></div> <br> <div id="bloop_sign_1466965620093293056" class="bloop_sign"><div style="font-family:helvetica,arial;font-size:13px">-- <br>Adrian Zubarev<br>Sent with Airmail</div></div> <br><p class="airmail_on">Am 25. Juni 2016 um 10:45:04, Adrian Zubarev (<a href="mailto:adrian.zubarev@devandartist.com">adrian.zubarev@devandartist.com</a>) schrieb:</p> <blockquote type="cite" class="clean_bq"><span><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;"><div></div><div>
<title></title>
<div class="bloop_markdown">
<p>Originally I started this topic in a discussion thread but moved
it now into its own proposal thread due the lack of feedback.</p>
<p><strong>This proposal contains a breaking change!</strong></p>
<p>You can read a formatted version here: <a href="https://gist.github.com/DevAndArtist/8f1113b6d5d0379ebf82bd227cf4a88d">
https://gist.github.com/DevAndArtist/8f1113b6d5d0379ebf82bd227cf4a88d</a></p>
<p>Feel free to also provide feedback if you spot any typos or
language mistakes I might have made.</p>
<hr>
<h1 id="revisingaccessmodifiersonextensions">Revising access
modifiers on extensions</h1>
<ul>
<li>Proposal: <a href="NNNN-filename.md">SE-NNNN</a></li>
<li>Author: <a href="https://github.com/DevAndArtist">Adrian
Zubarev</a></li>
<li>Status: <strong><a href="#rationale">Awaiting
review</a></strong></li>
<li>Review manager: TBD</li>
</ul>
<h2 id="introduction">Introduction</h2>
<p>One great goal for Swift 3 is to sort out any source breaking
language changes. This proposal aims to fix access modifier
inconsistency on extensions compared to other scope declarations
types.</p>
<p>Swift-evolution thread: <a href="">[Proposal] Revising access
modifiers on extensions</a></p>
<h2 id="motivation">Motivation</h2>
<p>When declaring members on extensions which don’t have an
explicit access modifier in Swift 2.2, it is possible to create an
<strong>implicitly public extension</strong> by applying a
<em>public</em> modifier to at least one extension member.</p>
<pre><code class="swift">public struct A { … }
/* implicitly public */ extension A {
public var member1: SomeType { … }
/* implicitly internal */ func member2() { … }
}
/* implicitly internal */ extension A {
/* implicitly internal */ var member3: SomeType { … }
}
</code></pre>
<p>Furthermore in Swift 2.2 it is not allowed to apply an
<em>access modifier</em> on extensions when a <em>type inheritance
clause</em> is present:</p>
<pre><code class="swift">public protocol B { … }
// 'public' modifier cannot be used with
// extensions that declare protocol conformances
public extension A : B { … }
</code></pre>
<h2 id="proposedsolution">Proposed solution</h2>
<ol>
<li>
<p>Allow access modifier on extension when a type inheritance
clause is present.</p>
</li>
<li>
<p>Remove the behavior of an implicit public extension.</p>
</li>
</ol>
<p>This changes should make access modifier on extensions
consistent to classes, structs and enums (and <a href="https://github.com/apple/swift-evolution/blob/master/proposals/0025-scoped-access-level.md">
SE–0025</a>).</p>
<h5 id="thecurrentgrammarwillnotchange:">The current grammar will
not change:</h5>
<p><em>extension-declaration</em> →
<em>access-level-modifier</em><sub>opt</sub>
<strong>extension</strong> <em>type-identifier</em>
<em>type-inheritance-clause</em><sub>opt</sub>
<em>extension-body</em></p>
<p><em>extension-declaration</em> →
<em>access-level-modifier</em><sub>opt</sub>
<strong>extension</strong> <em>type-identifier</em>
<em>requirement-clause</em> <em>extension-body</em></p>
<p><em>extension-body</em> → <strong>{</strong>
<em>declarations</em><sub>opt</sub> <strong>}</strong></p>
<p>Iff the <em>access-level-modifier</em> is not present, the
access modifier on extensions should always be implicitly
<strong>internal</strong>.</p>
<h5 id="publicapi:">Public Api:</h5>
<p>Current version:</p>
<pre><code class="swift">//===— Implementation version —===//
public protocol Y {
func member()
}
public struct X { … }
/* implicitly public */ extension X : Y {
public func member() { … }
/* implicitly internal */ func anotherMember() { … }
}
//===— Imported modele version —===//
public protocol Y {
func member()
}
public struct X { … }
public extension X : Y {
public func member() { … }
}
</code></pre>
<p>New Version:</p>
<pre><code class="swift">//===— Implementation version —===//
…
public extension X : Y {
public func member() { … }
/* implicitly internal */ func anotherMember() { … }
}
//===— Imported modele version —===//
…
public extension X : Y {
public func member() { … }
}
</code></pre>
<h2 id="impactonexistingcode">Impact on existing code</h2>
<p>This is a source-breaking change that can be automated by a
migrator, by simply scanning the <em>extension-body</em> for at
least one <em>public</em> modifier on its members. Iff a
<em>public</em> modifier was found on any member, the migrator can
add an explicit <em>public</em> modifier to the extension
itself.</p>
<h2 id="alternativesconsidered">Alternatives considered</h2>
<ul>
<li>No other alternative were considered for this proposal.</li>
</ul>
<h2 id="rationale">Rationale</h2>
<p>On [Date], the core team decided to <strong>(TBD)</strong> this
proposal. When the core team makes a decision regarding this
proposal, their rationale for the decision will be written
here.</p>
</div>
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<br>
<div id="bloop_sign_1466841186407026176" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
-- <br>
Adrian Zubarev<br>
Sent with Airmail</div>
</div>
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<div class="bloop_markdown"></div>
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