[stdlib] generalize Array(unsafeUninitializedCapacity:initializingWith:)

Author: glessard

stdlib/public/core/Array.swift

@@ -1509,15 +1509,34 @@ extension Array {
 }
 
 extension Array {
-  /// Implementation for Array(unsafeUninitializedCapacity:initializingWith:)
+  /// Implementation preserved (for ABI reasons) for:
+  /// Array(unsafeUninitializedCapacity:initializingWith:)
   /// and ContiguousArray(unsafeUninitializedCapacity:initializingWith:)
-  @inlinable
+  /*@_spi(SwiftStdlibLegacyABI)*/ @available(swift, obsoleted: 1)
+  @inlinable // inlinable is necessary for prespecialization
   internal init(
     _unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
       _ initializedCount: inout Int) throws -> Void
   ) rethrows {
+    try unsafe self.init(
+      _unsafeUninitializedCapacity: _unsafeUninitializedCapacity,
+      initializingWithTypedThrowsInitializer: initializer
+    )
+  }
+
+  /// Implementation for:
+  /// Array(unsafeUninitializedCapacity:initializingWith:)
+  /// and ContiguousArray(unsafeUninitializedCapacity:initializingWith:)
+  @_alwaysEmitIntoClient
+  internal init<E: Error>(
+    _unsafeUninitializedCapacity: Int,
+    initializingWithTypedThrowsInitializer initializer: (
+      _ buffer: inout UnsafeMutableBufferPointer<Element>,
+      _ initializedCount: inout Int
+    ) throws(E) -> Void
+  ) throws(E) {
     var firstElementAddress: UnsafeMutablePointer<Element>
     unsafe (self, firstElementAddress) =
       unsafe Array._allocateUninitialized(_unsafeUninitializedCapacity)
@@ -1567,15 +1586,17 @@ extension Array {
   ///         which begins as zero. Set `initializedCount` to the number of
   ///         elements you initialize.
   @_alwaysEmitIntoClient @inlinable
-  public init(
+  public init<E: Error>(
     unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
-      _ initializedCount: inout Int) throws -> Void
-  ) rethrows {
+      _ initializedCount: inout Int
+    ) throws(E) -> Void
+  ) throws(E) {
     self = try unsafe Array(
       _unsafeUninitializedCapacity: unsafeUninitializedCapacity,
-      initializingWith: initializer)
+      initializingWithTypedThrowsInitializer: initializer
+    )
   }
 
   // Superseded by the typed-throws version of this function, but retained

stdlib/public/core/ContiguousArray.swift

@@ -1105,15 +1105,15 @@ extension ContiguousArray {
   ///         which begins as zero. Set `initializedCount` to the number of
   ///         elements you initialize.
   @_alwaysEmitIntoClient @inlinable
-  public init(
+  public init<E>(
     unsafeUninitializedCapacity: Int,
     initializingWith initializer: (
       _ buffer: inout UnsafeMutableBufferPointer<Element>,
-      _ initializedCount: inout Int) throws -> Void
-  ) rethrows {
+      _ initializedCount: inout Int) throws(E) -> Void
+  ) throws(E) {
     self = try unsafe ContiguousArray(Array(
       _unsafeUninitializedCapacity: unsafeUninitializedCapacity,
-      initializingWith: initializer))
+      initializingWithTypedThrowsInitializer: initializer))
   }
 
   // Superseded by the typed-throws version of this function, but retained

stdlib/public/core/Sort.swift

@@ -675,7 +675,7 @@ extension UnsafeMutableBufferPointer {
     //
     // There's no need to set the initialized count within the initializing
     // closure, since the buffer is guaranteed to be uninitialized at exit.
-    _ = try unsafe Array<Element>(_unsafeUninitializedCapacity: count / 2) {
+    _ = try unsafe Array<Element>(unsafeUninitializedCapacity: count / 2) {
       buffer, _ in
       var runs: [Range<Index>] = []