[stdlib][swift-3-indexing-model] speeding up the compilation

Author: Max Moiseev

stdlib/public/core/LazyCollection.swift.gyb

@@ -235,13 +235,6 @@ extension ${TraversalCollection} where Self : LazyCollectionProtocol {
 
 % end
 
-extension LazyCollectionProtocol {
-  /// Identical to `self`.
-  public var lazy: Self { // Don't re-wrap already-lazy collections
-    return self
-  }
-}
-
 @available(*, unavailable, renamed: "LazyCollectionProtocol")
 public typealias LazyCollectionType = LazyCollectionProtocol
 

test/1_stdlib/Inputs/flatMap.gyb

@@ -12,12 +12,15 @@ ${Test}.test("flatMap/${Kind}/Lazy") {
       elements: test.sequence.map(OpaqueValue.init))
     let closureLifetimeTracker = LifetimeTracked(0)
     var timesClosureWasCalled = 0
-    var result = s.lazy.flatMap {
+
+    let lazySeq = s.lazy
+    var result = lazySeq.flatMap {
       (element: OpaqueValue<Int>) -> ${Minimal}<OpaqueValue<Int32>> in
       _blackHole(closureLifetimeTracker)
       timesClosureWasCalled += 1
+      let elements = test.transform(element.value)
       return ${Minimal}<OpaqueValue<Int32>>(
-        elements: test.transform(element.value).map { OpaqueValue(Int32($0)) })
+        elements: elements.map { OpaqueValue($0) })
     }
     expectEqual(0, timesClosureWasCalled, "Unexpected eagerness")
 
@@ -47,8 +50,9 @@ ${Test}.test("flatMap/${Kind}/Lazy") {
 
     // FIXME: we are not calling check${Kind} because of the same issue again.
     // <rdar://problem/21989896>
+    let expected = test.expected.map(OpaqueValue.init)
     expectEqualSequence(
-      test.expected.map(OpaqueValue.init), result,
+      expected, result,
       stackTrace: SourceLocStack().with(test.loc)
     ) { $0.value == $1.value }
 %   end

test/1_stdlib/Map.swift

@@ -36,21 +36,25 @@ extension LazyMapCollection where Base : TestProtocol1, Element : TestProtocol1
 // CHECK: testing...
 print("testing...")
 
-// Test mapping a collection
-// CHECK-NEXT: [6, 9, 12, 15, 18, 21]
-let a = Array((2..<8).lazy.map { $0 * 3 })
-print(a)
-
-// Test mapping a sequence
-let s = a.makeIterator().lazy.map { $0 / 3 }
-// CHECK-NEXT: <2, 3, 4, 5, 6, 7>
-print("<", terminator: "")
-var prefix = ""
-for x in s {
-  print("\(prefix)\(x)", terminator: "")
-  prefix = ", "
+do {
+  // Test mapping a collection
+  // CHECK-NEXT: [6, 9, 12, 15, 18, 21]
+  let lazyRange = (2..<8).lazy
+  let a = Array(lazyRange.map { $0 * 3 })
+  print(a)
+
+  // Test mapping a sequence
+  let lazySeq = a.makeIterator().lazy
+  let s = lazySeq.map { $0 / 3 }
+  // CHECK-NEXT: <2, 3, 4, 5, 6, 7>
+  print("<", terminator: "")
+  var prefix = ""
+  for x in s {
+    print("\(prefix)\(x)", terminator: "")
+    prefix = ", "
+  }
+  print(">")
 }
-print(">")
 
 //===--- Avoid creating gratuitously self-destructive sequences -----------===//
 

test/1_stdlib/Range.swift.gyb

@@ -127,8 +127,11 @@ RangeTestSuite.test("map()") {
 }
 
 RangeTestSuite.test("reversed()") {
-  var result = (0..<10).lazy.reversed()
-  expectType(Array<Int>.self, &result)
+  let lazyRange = (0..<10).lazy
+  var result = lazyRange.reversed()
+  typealias Expected = LazyRandomAccessCollection<
+    ReversedRandomAccessCollection<CountableRange<Int>>>
+    expectType(Expected.self, &result)
   expectEqualSequence(
     [ 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 ],
     result)

test/1_stdlib/StringAPI.swift

@@ -244,9 +244,15 @@ func checkHasPrefixHasSuffix(
     }
   let expectHasPrefix = lhsNFDGraphemeClusters.starts(
     with: rhsNFDGraphemeClusters, isEquivalent: (==))
+
+  let lazyLhs = lhsNFDGraphemeClusters.lazy
+  let reversedLhs = lazyLhs.reversed()
+
+  let lazyRhs = rhsNFDGraphemeClusters.lazy
+  let reversedRhs = lazyRhs.reversed()
+
   let expectHasSuffix =
-    lhsNFDGraphemeClusters.lazy.reversed().starts(
-      with: rhsNFDGraphemeClusters.lazy.reversed(), isEquivalent: (==))
+    reversedLhs.starts(with: reversedRhs, isEquivalent: (==))
 
   expectEqual(expectHasPrefix, lhs.hasPrefix(rhs), stackTrace: stackTrace)
   expectEqual(

validation-test/stdlib/Arrays.swift.gyb

@@ -624,11 +624,12 @@ for (step, evilBoundsCheck) in [ (1, true), (-1, false), (-1, true) ] {
   }
 
   for (op, rangeMax) in ["Grow":0, "Shrink":200] {
+    let lazyRange = (0..<200).lazy
     let t3 =  ArrayTestSuite.test("\(testPrefix)/replaceSubrange/\(op)Unique")
     (_isDebugAssertConfiguration() ? t3.crashOutputMatches(message) : t3)
     .code {
       let evil = EvilCollection(step, boundsChecked: evilBoundsCheck)
-      var a = Array((0..<200).lazy.map { LifetimeTracked($0) })
+      var a = Array(lazyRange.map { LifetimeTracked($0) })
       if expectedToFail {
         expectCrashLater()
       }
@@ -639,7 +640,7 @@ for (step, evilBoundsCheck) in [ (1, true), (-1, false), (-1, true) ] {
     (_isDebugAssertConfiguration() ? t4.crashOutputMatches(message) : t4)
     .code {
       let evil = EvilCollection(step, boundsChecked: evilBoundsCheck)
-      var a = Array((0..<200).lazy.map { LifetimeTracked($0) })
+      var a = Array(lazyRange.map { LifetimeTracked($0) })
       var b = a
       if expectedToFail {
         expectCrashLater()

validation-test/stdlib/CollectionType.swift.gyb

@@ -716,9 +716,11 @@ CollectionTypeTests.test("index(of:)/ContinueSearch") {
     let c = MinimalCollection(
       elements: [1, 2, 1, 3, 1].map(MinimalEquatableValue.init))
     let foundIndices = c._test_indicesOf(MinimalEquatableValue(1))
+    let actual = foundIndices.map { c.distance(from: c.startIndex, to: $0) }
     expectEqualSequence(
       [ 0, 2, 4 ],
-      foundIndices.map { c.distance(from: c.startIndex, to: $0) })
+      actual
+      )
   }
 }