Remove RandomAccess overloads and types

Author: Russ Bishop

stdlib/public/core/Filter.swift.gyb

@@ -165,7 +165,7 @@ public func > <Base : Collection>(
 // collapsed into one `LazyFilterCollection` using conditional conformances.
 // Maybe even combined with `LazyFilterSequence`.
 
-% for Traversal in ['Forward', 'Bidirectional', 'RandomAccess']:
+% for Traversal in ['Forward', 'Bidirectional']:
 %   Self = "LazyFilter" + collectionForTraversal(Traversal)
 %   Slice = sliceTypeName(traversal=Traversal, mutable=False, rangeReplaceable=False)
 
@@ -244,7 +244,7 @@ public struct ${Self}<
     i = LazyFilterIndex(base: index)
   }
 
-%   if Traversal == 'Bidirectional' or Traversal == 'RandomAccess':
+%   if Traversal == 'Bidirectional':
   @warn_unused_result
   public func index(before i: Index) -> Index {
     var i = i
@@ -315,7 +315,7 @@ extension LazySequenceProtocol {
   }
 }
 
-% for Traversal in ['Forward', 'Bidirectional', 'RandomAccess']:
+% for Traversal in ['Forward', 'Bidirectional']:
 
 extension LazyCollectionProtocol
   where

stdlib/public/core/FlatMap.swift

@@ -127,28 +127,3 @@ extension LazyCollectionProtocol
     return self.map(transform).filter { $0 != nil }.map { $0! }
   }
 }
-
-extension LazyCollectionProtocol
-  where
-  Self : RandomAccessCollection,
-  Elements : RandomAccessCollection
-{
-  /// Returns a `LazyMapRandomAccessCollection` containing the concatenated non-nil
-  /// results of mapping transform over this collection.  The elements of
-  /// the result are computed lazily, each time they are read.
-  ///
-  /// Use this method to receive only nonoptional values when your
-  /// transformation produces an optional value.
-  ///
-  /// - Parameter transform: A closure that accepts an element of this
-  /// collection as its argument and returns an optional value.
-  public func flatMap<U>(
-    _ transform: (Self.Elements.Iterator.Element) -> U?
-  ) -> LazyMapRandomAccessCollection<
-    LazyFilterRandomAccessCollection<
-      LazyMapRandomAccessCollection<Self.Elements, U?>>,
-    U
-  > {
-    return self.map(transform).filter { $0 != nil }.map { $0! }
-  }
-}

validation-test/stdlib/Lazy.swift.gyb

@@ -1161,20 +1161,6 @@ tests.test("LazyFilterBidirectionalCollection/AssociatedTypes") {
     indicesType: DefaultBidirectionalIndices<Subject>.self)
 }
 
-tests.test("LazyFilterRandomAccessCollection/AssociatedTypes") {
-  typealias Base = MinimalRandomAccessCollection<OpaqueValue<Int>>
-  typealias Subject = LazyFilterRandomAccessCollection<Base>
-  expectRandomAccessCollectionAssociatedTypes(
-    collectionType: Subject.self,
-    iteratorType: LazyFilterIterator<Base.Iterator>.self,
-    // FIXME(ABI): SubSequence should be `LazyFilterRandomAccessCollection<Base.Slice>`.
-    subSequenceType: RandomAccessSlice<Subject>.self,
-    indexType: LazyFilterIndex<Base>.self,
-    indexDistanceType: Base.IndexDistance.self,
-    indicesType: DefaultRandomAccessIndices<Subject>.self)
-}
-
-
 tests.test("lazy.filter/TypeInference") {
   let baseArray: [OpaqueValue<Int>] = (0..<10).map(OpaqueValue.init)
   do {
@@ -1204,7 +1190,7 @@ tests.test("lazy.filter/TypeInference") {
     var filtered = MinimalRandomAccessCollection(elements: baseArray)
       .lazy.filter { _ in true }
     expectType(
-      LazyFilterRandomAccessCollection<
+      LazyFilterBidirectionalCollection<
         MinimalRandomAccessCollection<OpaqueValue<Int>>
       >.self,
       &filtered)
@@ -1297,22 +1283,5 @@ do {
   }
 }
 
-% for Traversal in TRAVERSALS:
-%		TraversalCollection = collectionForTraversal(Traversal)
-tests.test("${TraversalCollection}/lazy/flatMap") {
-	let sample = (0..<100)
-	let expected = sample.filter { $0 % 3 != 0 }.map { String($0) }
-	let base = Minimal${TraversalCollection}(elements: sample).lazy
-
-	var calls = 0
-	let mapped = sample.lazy.flatMap { (x) -> String? in
-		calls += 1
-		return x % 3 != 0 ? String(x) : nil
-	}
-	expectEqual(0, calls, "unexpected eagerness in \(base.dynamicType).flatMap")
-	
-	checkSequence(expected, mapped, resiliencyChecks: .none)
-}
-%end
-
 runAllTests()
+