revert changes to stdlib

Author: airspeedswift

stdlib/public/core/ArrayBufferProtocol.swift

@@ -16,7 +16,10 @@
 internal protocol _ArrayBufferProtocol
   : MutableCollection, RandomAccessCollection {
 
-  associatedtype Indices = CountableRange<Int>
+  associatedtype Indices 
+  // FIXME(ABI) (Revert Where Clauses): Remove this conformance
+  : RandomAccessCollection 
+    = CountableRange<Int>
 
   /// The type of elements stored in the buffer.
   associatedtype Element

stdlib/public/core/BidirectionalCollection.swift

@@ -66,7 +66,9 @@ public protocol _BidirectionalIndexable : _Indexable {
 /// - If `i > c.startIndex && i <= c.endIndex`
 ///   `c.index(after: c.index(before: i)) == i`.
 public protocol BidirectionalCollection : _BidirectionalIndexable, Collection 
-where SubSequence: BidirectionalCollection, Indices: BidirectionalCollection {
+// FIXME(ABI) (Revert Where Clauses): Restore these 
+// where SubSequence: BidirectionalCollection, Indices: BidirectionalCollection
+{
 
 // TODO: swift-3-indexing-model - replaces functionality in BidirectionalIndex
   /// Returns the position immediately before the given index.
@@ -84,11 +86,17 @@ where SubSequence: BidirectionalCollection, Indices: BidirectionalCollection {
 
   /// A sequence that can represent a contiguous subrange of the collection's
   /// elements.
-  associatedtype SubSequence = BidirectionalSlice<Self>
+  associatedtype SubSequence
+  // FIXME(ABI) (Revert Where Clauses): Remove these conformances
+  : _BidirectionalIndexable, Collection
+    = BidirectionalSlice<Self>
 
   /// A type that represents the indices that are valid for subscripting the
   /// collection, in ascending order.
-  associatedtype Indices = DefaultBidirectionalIndices<Self>
+  associatedtype Indices 
+  // FIXME(ABI) (Revert Where Clauses): Remove these conformances
+  : _BidirectionalIndexable, Collection
+    = DefaultBidirectionalIndices<Self>
 
   /// The indices that are valid for subscripting the collection, in ascending
   /// order.

stdlib/public/core/Collection.swift

@@ -647,9 +647,8 @@ public struct IndexingIterator<
 /// count the number of contained elements, accessing its `count` property is
 /// an O(*n*) operation.
 public protocol Collection : _Indexable, Sequence 
-where SubSequence: Collection, Indices: Collection,
-      SubSequence.Index == Index, 
-      SubSequence.Iterator.Element == Iterator.Element 
+// FIXME(ABI) (Revert Where Clauses): Restore these 
+// where SubSequence: Collection, Indices: Collection,
 {
   /// A type that represents the number of steps between a pair of
   /// indices.
@@ -676,9 +675,15 @@ where SubSequence: Collection, Indices: Collection,
   /// This associated type appears as a requirement in the `Sequence`
   /// protocol, but it is restated here with stricter constraints. In a
   /// collection, the subsequence should also conform to `Collection`.
-  associatedtype SubSequence = Slice<Self>
-      where Iterator.Element == SubSequence.Iterator.Element,
-            SubSequence.SubSequence == SubSequence
+  associatedtype SubSequence
+  // FIXME(ABI) (Revert Where Clauses): remove these conformances:
+  : _IndexableBase, Sequence
+     = Slice<Self>
+      where SubSequence.SubSequence == SubSequence
+  // FIXME(ABI) (Revert Where Clauses): and this where clause:
+          , Iterator.Element == SubSequence.Iterator.Element
+          , SubSequence.Index == Index
+            
 
   // FIXME(ABI)#98 (Recursive Protocol Constraints):
   // FIXME(ABI)#99 (Associated Types with where clauses):
@@ -740,10 +745,15 @@ where SubSequence: Collection, Indices: Collection,
 
   /// A type that represents the indices that are valid for subscripting the
   /// collection, in ascending order.
-  associatedtype Indices = DefaultIndices<Self>
-    where Indices.Iterator.Element == Index,
+  associatedtype Indices
+  // FIXME(ABI) (Revert Where Clauses): Remove these two conformances 
+  : _Indexable, Sequence
+    = DefaultIndices<Self>
+    where Indices.Iterator.Element == Index, 
           Indices.Index == Index
-
+  // FIXME(ABI) (Revert Where Clauses): Remove this where clause
+        , Indices.SubSequence == Indices
+        
   // FIXME(ABI)#100 (Recursive Protocol Constraints):
   // associatedtype Indices : Collection
   //   where

stdlib/public/core/ExistentialCollection.swift.gyb

@@ -423,14 +423,21 @@ internal class _AnyRandomAccessCollectionBox<Element>
 %     assert False, 'Unknown kind'
 %   end
 
+
+
 @_fixed_layout
 @_versioned
 internal final class _${Kind}Box<S : ${Kind}> : _Any${Kind}Box<S.Iterator.Element>
-%  if Kind == 'Sequence':
   where
   S.SubSequence : ${Kind},
+// FIXME(ABI) (Revert Where Clauses): apply all this only to Sequence:
+%  if Kind == 'Sequence':
   S.SubSequence.Iterator.Element == S.Iterator.Element,
   S.SubSequence.SubSequence == S.SubSequence
+// FIXME(ABI) (Revert Where Clauses): remove this else clause:
+%  else:
+  S.SubSequence.Indices : ${Kind},
+  S.Indices : ${Kind}
 %  end
 {
   internal typealias Element = S.Iterator.Element
@@ -1035,8 +1042,12 @@ public struct ${Self}<Element>
   @_inlineable
   public init<C : ${SubProtocol}>(_ base: C)
     where
-    // FIXME(ABI)#101 (Associated Types with where clauses): these constraints should be applied to
-    // associated types of Collection.
+    // FIXME(ABI) (Revert Where Clauses): remove next 3 lines
+    C.SubSequence : ${SubProtocol},
+    C.SubSequence.Indices : ${SubProtocol},
+    C.Indices : ${SubProtocol},
+    // FIXME(ABI)#101 (Associated Types with where clauses): these constraints
+    // should be applied to associated types of Collection.
     C.SubSequence.Iterator.Element == Element
      {
     // Traversal: ${Traversal}

stdlib/public/core/Mirror.swift

@@ -214,7 +214,10 @@ public struct Mirror {
     children: C,
     displayStyle: DisplayStyle? = nil,
     ancestorRepresentation: AncestorRepresentation = .generated
-  ) where C.Iterator.Element == Child {
+  ) where C.Iterator.Element == Child 
+  // FIXME(ABI) (Revert Where Clauses): Remove these 
+  , C.SubSequence : Collection, C.SubSequence.Indices : Collection, C.Indices : Collection
+  {
 
     self.subjectType = Subject.self
     self._makeSuperclassMirror = Mirror._superclassIterator(
@@ -261,7 +264,10 @@ public struct Mirror {
     unlabeledChildren: C,
     displayStyle: DisplayStyle? = nil,
     ancestorRepresentation: AncestorRepresentation = .generated
-  ) {
+  ) 
+  // FIXME(ABI) (Revert Where Clauses): Remove these two clauses
+  where C.SubSequence : Collection, C.Indices : Collection
+  {
 
     self.subjectType = Subject.self
     self._makeSuperclassMirror = Mirror._superclassIterator(

stdlib/public/core/MutableCollection.swift

@@ -197,8 +197,13 @@ public protocol _MutableIndexable : _Indexable {
 ///     a[i] = x
 ///     let y = x
 public protocol MutableCollection : _MutableIndexable, Collection
-where SubSequence: MutableCollection {
-  associatedtype SubSequence = MutableSlice<Self>
+// FIXME(ABI) (Revert Where Clauses): restore this:
+// where SubSequence: MutableCollection
+{
+  associatedtype SubSequence
+  // FIXME(ABI) (Revert Where Clauses): remove this conformance:
+  : Collection
+   = MutableSlice<Self>
 
   /// Accesses the element at the specified position.
   ///

stdlib/public/core/RandomAccessCollection.swift

@@ -48,15 +48,22 @@ public protocol _RandomAccessIndexable : _BidirectionalIndexable {
 /// `distance(from:to:)` methods with O(1) efficiency.
 public protocol RandomAccessCollection :
   _RandomAccessIndexable, BidirectionalCollection
-  where SubSequence: RandomAccessCollection, Indices: RandomAccessCollection
+// FIXME(ABI) (Revert Where Clauses): Restore this:
+// where SubSequence: RandomAccessCollection, Indices: RandomAccessCollection
 {
   /// A collection that represents a contiguous subrange of the collection's
   /// elements.
-  associatedtype SubSequence = RandomAccessSlice<Self>
+  associatedtype SubSequence
+  // FIXME(ABI) (Revert Where Clauses): Remove these two constraints:
+   : _RandomAccessIndexable, BidirectionalCollection
+   = RandomAccessSlice<Self>
 
   /// A type that represents the indices that are valid for subscripting the
   /// collection, in ascending order.
-  associatedtype Indices = DefaultRandomAccessIndices<Self>
+  associatedtype Indices 
+  // FIXME(ABI) (Revert Where Clauses): Remove these two constraints:
+  : _RandomAccessIndexable, BidirectionalCollection
+  = DefaultRandomAccessIndices<Self>
 
   /// The indices that are valid for subscripting the collection, in ascending
   /// order.