Revert "Refactor Mirror to reduce metadata allocation (#32041) (#32957)"

This reverts commit a7542a5.

Author: airspeedswift

stdlib/public/core/CMakeLists.txt

@@ -60,7 +60,6 @@ set(SWIFTLIB_ESSENTIAL
   DictionaryVariant.swift
   DropWhile.swift
   Dump.swift
-  EitherSequence.swift
   EmptyCollection.swift
   Equatable.swift
   ErrorType.swift

stdlib/public/core/DebuggerSupport.swift

@@ -110,7 +110,7 @@ public enum _DebuggerSupport {
 
   private static func ivarCount(mirror: Mirror) -> Int {
     let ivars = mirror.superclassMirror.map(ivarCount) ?? 0
-    return ivars + mirror._children.count
+    return ivars + mirror.children.count
   }
 
   private static func shouldExpand(
@@ -119,7 +119,7 @@ public enum _DebuggerSupport {
     isRoot: Bool
   ) -> Bool {
     if isRoot || collectionStatus.isCollection { return true }
-    if !mirror._children.isEmpty { return true }
+    if !mirror.children.isEmpty { return true }
     if mirror.displayStyle == .`class` { return true }
     if let sc = mirror.superclassMirror { return ivarCount(mirror: sc) > 0 }
     return true
@@ -154,7 +154,7 @@ public enum _DebuggerSupport {
     // anyway, so there's that...
     let willExpand = mirror.displayStyle != .`class` || value is CustomReflectable?
 
-    let count = mirror._children.count
+    let count = mirror.children.count
     let bullet = isRoot && (count == 0 || !willExpand) ? ""
       : count == 0    ? "- "
       : maxDepth <= 0 ? "▹ " : "▿ "
@@ -202,7 +202,7 @@ public enum _DebuggerSupport {
         target: &target)
     }
 
-    for (optionalName,child) in mirror._children {
+    for (optionalName,child) in mirror.children {
       let childName = optionalName ?? "\(printedElements)"
       if maxItemCounter <= 0 {
         print(String(repeating: " ", count: indent+4), terminator: "", to: &target)

stdlib/public/core/Dump.swift

@@ -99,7 +99,7 @@ internal func _dump_unlocked<TargetStream: TextOutputStream>(
   for _ in 0..<indent { target.write(" ") }
 
   let mirror = Mirror(reflecting: value)
-  let count = mirror._children.count
+  let count = mirror.children.count
   let bullet = count == 0    ? "-"
              : maxDepth <= 0 ? "▹" : "▿"
   target.write(bullet)
@@ -149,7 +149,7 @@ internal func _dump_unlocked<TargetStream: TextOutputStream>(
       visitedItems: &visitedItems)
   }
 
-  var currentIndex = mirror._children.startIndex
+  var currentIndex = mirror.children.startIndex
   for i in 0..<count {
     if maxItemCounter <= 0 {
       for _ in 0..<(indent+4) {
@@ -167,8 +167,8 @@ internal func _dump_unlocked<TargetStream: TextOutputStream>(
       return
     }
 
-    let (name, child) = mirror._children[currentIndex]
-    mirror._children.formIndex(after: &currentIndex)
+    let (name, child) = mirror.children[currentIndex]
+    mirror.children.formIndex(after: &currentIndex)
     _dump_unlocked(
       child,
       to: &target,
@@ -196,7 +196,7 @@ internal func _dumpSuperclass_unlocked<TargetStream: TextOutputStream>(
 
   for _ in 0..<indent { target.write(" ") }
 
-  let count = mirror._children.count
+  let count = mirror.children.count
   let bullet = count == 0    ? "-"
              : maxDepth <= 0 ? "▹" : "▿"
   target.write(bullet)
@@ -216,7 +216,7 @@ internal func _dumpSuperclass_unlocked<TargetStream: TextOutputStream>(
       visitedItems: &visitedItems)
   }
 
-  var currentIndex = mirror._children.startIndex
+  var currentIndex = mirror.children.startIndex
   for i in 0..<count {
     if maxItemCounter <= 0 {
       for _ in 0..<(indent+4) {
@@ -234,8 +234,8 @@ internal func _dumpSuperclass_unlocked<TargetStream: TextOutputStream>(
       return
     }
 
-    let (name, child) = mirror._children[currentIndex]
-    mirror._children.formIndex(after: &currentIndex)
+    let (name, child) = mirror.children[currentIndex]
+    mirror.children.formIndex(after: &currentIndex)
     _dump_unlocked(
       child,
       to: &target,

stdlib/public/core/EitherSequence.swift

@@ -64,7 +64,6 @@
     "RandomAccessCollection.swift",
     "MutableCollection.swift",
     "CollectionAlgorithms.swift",
-    "EitherSequence.swift",
     "EmptyCollection.swift",
     "Stride.swift",
     "Repeat.swift",