[stdlib] Cleanup DefaultIndices, delete dead code (#13952)

* Remove a bunch of Default(Bidirectional|RandomAccess)Indices usage from stdlib and test

* Remove some DefaultRandomAccessIndices and IndexDistance usage from Foundation

* Remove no-longer-used internal type in Existentials.swift

* Get rid of indicesForTraversal

Author: airspeedswift

stdlib/public/SDK/Dispatch/Data.swift

@@ -15,7 +15,7 @@ import _SwiftDispatchOverlayShims
 public struct DispatchData : RandomAccessCollection, _ObjectiveCBridgeable {
 	public typealias Iterator = DispatchDataIterator
 	public typealias Index = Int
-	public typealias Indices = DefaultRandomAccessIndices<DispatchData>
+	public typealias Indices = DefaultIndices<DispatchData>
 
 	public static let empty: DispatchData = DispatchData(data: _swift_dispatch_data_empty())
 

stdlib/public/SDK/Foundation/IndexPath.swift

@@ -22,7 +22,7 @@ public struct IndexPath : ReferenceConvertible, Equatable, Hashable, MutableColl
     public typealias ReferenceType = NSIndexPath
     public typealias Element = Int
     public typealias Index = Array<Int>.Index
-    public typealias Indices = DefaultRandomAccessIndices<IndexPath>
+    public typealias Indices = DefaultIndices<IndexPath>
 
     fileprivate enum Storage : ExpressibleByArrayLiteral {
         typealias Element = Int

stdlib/public/SDK/Foundation/IndexSet.swift

@@ -656,7 +656,7 @@ public struct IndexSet : ReferenceConvertible, Equatable, BidirectionalCollectio
     }
 
     /// For a positive delta, shifts the indexes in [index, INT_MAX] to the right, thereby inserting an "empty space" [index, delta], for a negative delta, shifts the indexes in [index, INT_MAX] to the left, thereby deleting the indexes in the range [index - delta, delta].
-    public mutating func shift(startingAt integer: Element, by delta: IndexSet.IndexDistance) {
+    public mutating func shift(startingAt integer: Element, by delta: Int) {
         _applyMutation { $0.shiftIndexesStarting(at: integer, by: delta) }
     }
 

stdlib/public/core/CMakeLists.txt

@@ -53,7 +53,6 @@ set(SWIFTLIB_ESSENTIAL
   EmptyCollection.swift
   Equatable.swift
   ErrorType.swift
-  Existential.swift
   Filter.swift
   FixedArray.swift.gyb
   FlatMap.swift

stdlib/public/core/Existential.swift

@@ -1040,9 +1040,7 @@ public struct ${Self}<Element> {
 }
 
 extension ${Self}: ${SelfProtocol} {
-  public typealias Indices
-    = Default${Traversal.replace('Forward', '')}Indices<${Self}>
-
+  public typealias Indices = DefaultIndices<${Self}>
   public typealias Iterator = AnyIterator<Element>
   public typealias Index = AnyIndex
   public typealias SubSequence = ${Self}<Element> 

stdlib/public/core/ExistentialCollection.swift.gyb

@@ -60,7 +60,6 @@
     "SequenceAlgorithms.swift",
     "RangeReplaceableCollection.swift",
     "Indices.swift",
-    "Existential.swift",
     "WriteBackMutableSlice.swift",
     "UnfoldSequence.swift",
     "UIntBuffer.swift",

stdlib/public/core/GroupInfo.json

@@ -129,7 +129,7 @@ extension _UIntBuffer : BidirectionalCollection {
 }
 
 extension _UIntBuffer : RandomAccessCollection {
-  public typealias Indices = DefaultRandomAccessIndices<_UIntBuffer>
+  public typealias Indices = DefaultIndices<_UIntBuffer>
 
   @_inlineable // FIXME(sil-serialize-all)
   @inline(__always)

stdlib/public/core/UIntBuffer.swift

@@ -24,7 +24,6 @@ import StdlibUnittest
 from gyb_stdlib_support import (
     TRAVERSALS,
     collectionForTraversal,
-    defaultIndicesForTraversal,
 )
 
 }%

test/Prototypes/Algorithms.swift.gyb

@@ -39,18 +39,6 @@ def protocolsForCollectionFeatures(traversal, mutable, rangeReplaceable):  # noq
         protocols.append('RangeReplaceableCollection')
     return protocols
 
-
-def defaultIndicesForTraversal(traversal):  # noqa (N802)
-    if traversal == 'Forward':
-        return 'DefaultIndices'
-    elif traversal == 'Bidirectional':
-        return 'DefaultBidirectionalIndices'
-    elif traversal == 'RandomAccess':
-        return 'DefaultRandomAccessIndices'
-    else:
-        raise ValueError("Unknown traversal %r" % traversal)
-
-
 def documentationNameForTraversal(traversal):  # noqa (N802)
     if traversal == 'Forward':
         return 'collection'

utils/gyb_stdlib_support.py

@@ -14,7 +14,7 @@ protocol AnyCodeUnits_ {
 
 struct AnyCodeUnits : RandomAccessCollection, AnyCodeUnits_ {
   let me: AnyCodeUnits_
-  typealias Indices = DefaultRandomAccessIndices<AnyCodeUnits>
+  typealias Indices = DefaultIndices<AnyCodeUnits>
   var startIndex: Int64 { return me.startIndex }
   var endIndex: Int64 { return me.endIndex }
   func index(after i: Index) -> Index { return me.index(after: i) }

validation-test/compiler_crashers_2_fixed/0080-rdar30442622.swift

@@ -133,7 +133,7 @@ extension _UIntBuffer : BidirectionalCollection {
 }
 
 extension _UIntBuffer : RandomAccessCollection {
-  public typealias Indices = DefaultRandomAccessIndices<_UIntBuffer>
+  public typealias Indices = DefaultIndices<_UIntBuffer>
 
   @inline(__always)
   public func index(_ i: Index, offsetBy n: Int) -> Index {

validation-test/compiler_crashers_2_fixed/0109-sr4737.swift

@@ -7,7 +7,7 @@
 
 % import os.path
 % import gyb
-% from gyb_stdlib_support import TRAVERSALS, collectionForTraversal, defaultIndicesForTraversal
+% from gyb_stdlib_support import TRAVERSALS, collectionForTraversal
 
 import StdlibUnittest
 import StdlibCollectionUnittest
@@ -829,7 +829,6 @@ func ==(lhs: FatalIndex, rhs: FatalIndex) -> Bool { fatalError() }
 % for Traversal in TRAVERSALS:
 %   Collection = collectionForTraversal(Traversal)
 %   Self = 'Fatal' + Collection
-%   Indices = defaultIndicesForTraversal(Traversal)
 
 struct ${Self}<T> : ${Collection} {
   var startIndex: FatalIndex { fatalError() }
@@ -848,7 +847,7 @@ CollectionTypeTests.test("AssociatedTypes/${Collection}") {
     iteratorType: IndexingIterator<C>.self,
     subSequenceType: Slice<C>.self,
     indexType: FatalIndex.self,
-    indicesType: ${Indices}<C>.self)
+    indicesType: DefaultIndices<C>.self)
 }
 % end
 

validation-test/stdlib/CollectionType.swift.gyb

@@ -770,7 +770,7 @@ CountableClosedRangeTestSuite.test("AssociatedTypes") {
     iteratorType: IndexingIterator<Collection>.self,
     subSequenceType: RandomAccessSlice<Collection>.self,
     indexType: ClosedRangeIndex<MinimalStrideableValue>.self,
-    indicesType: DefaultRandomAccessIndices<Collection>.self)
+    indicesType: DefaultIndices<Collection>.self)
 }
 
 var MiscTestSuite = TestSuite("Misc")

validation-test/stdlib/Range.swift.gyb

@@ -5,7 +5,6 @@
 %{
 from gyb_stdlib_support import (
     TRAVERSALS,
-    defaultIndicesForTraversal,
     collectionTypeName
 )
 }%

validation-test/stdlib/Slice.swift.gyb

@@ -66,7 +66,7 @@ StringTests.test("AssociatedTypes-UTF8View") {
     iteratorType: View.Iterator.self,
     subSequenceType: Substring.UTF8View.self,
     indexType: View.Index.self,
-    indicesType: DefaultBidirectionalIndices<View>.self)
+    indicesType: DefaultIndices<View>.self)
 }
 
 StringTests.test("AssociatedTypes-UTF16View") {
@@ -86,7 +86,7 @@ StringTests.test("AssociatedTypes-UnicodeScalarView") {
     iteratorType: View.Iterator.self,
     subSequenceType: Substring.UnicodeScalarView.self,
     indexType: View.Index.self,
-    indicesType: DefaultBidirectionalIndices<View>.self)
+    indicesType: DefaultIndices<View>.self)
 }
 
 StringTests.test("AssociatedTypes-CharacterView") {
@@ -96,7 +96,7 @@ StringTests.test("AssociatedTypes-CharacterView") {
     iteratorType: IndexingIterator<View>.self,
     subSequenceType: View.self,
     indexType: View.Index.self,
-    indicesType: DefaultBidirectionalIndices<View>.self)
+    indicesType: DefaultIndices<View>.self)
 }
 
 func checkUnicodeScalarViewIteration(