[SE-0485, 6.2] OutputSpan and OutputRawSpan

Runtimes/Core/core/CMakeLists.txt

@@ -154,6 +154,8 @@ add_library(swiftCore
   Span/RawSpan.swift
   Span/MutableSpan.swift
   Span/MutableRawSpan.swift
+  Span/OutputSpan.swift
+  Span/OutputRawSpan.swift
   StaticString.swift
   StaticPrint.swift
   Stride.swift

stdlib/public/core/CMakeLists.txt

@@ -158,6 +158,8 @@ split_embedded_sources(
   EMBEDDED Sort.swift
   EMBEDDED Span/MutableRawSpan.swift
   EMBEDDED Span/MutableSpan.swift
+  EMBEDDED Span/OutputRawSpan.swift
+  EMBEDDED Span/OutputSpan.swift
   EMBEDDED Span/RawSpan.swift
   EMBEDDED Span/Span.swift
   EMBEDDED StaticString.swift

stdlib/public/core/GroupInfo.json

@@ -202,6 +202,8 @@
   "Span": [
     "MutableRawSpan.swift",
     "MutableSpan.swift",
+    "OutputRawSpan.swift",
+    "OutputSpan.swift",
     "RawSpan.swift",
     "Span.swift"
   ],

stdlib/public/core/InlineArray.swift

@@ -296,6 +296,25 @@ extension InlineArray where Element: ~Copyable {
     }
 #else
     fatalError()
+#endif
+  }
+
+  @available(SwiftStdlib 6.2, *)
+  @_alwaysEmitIntoClient
+  public init<E: Error>(
+    initializingWith initializer: (inout OutputSpan<Element>) throws(E) -> Void
+  ) throws(E) {
+#if $BuiltinEmplaceTypedThrows
+    _storage = try Builtin.emplace { (rawPtr) throws(E) -> () in
+      let buffer = unsafe Self._initializationBuffer(start: rawPtr)
+      _internalInvariant(Self.count == buffer.count)
+      var output = unsafe OutputSpan(buffer: buffer, initializedCount: 0)
+      try initializer(&output)
+      let initialized = unsafe output.finalize(for: buffer)
+      _precondition(count == initialized, "InlineArray initialization underflow")
+    }
+#else
+    fatalError()
 #endif
   }
 }