[Printing] Print tuple labels when available.

When printing a tuple via print(...), print tuple labels when they are
available. This is possible now that the runtime metadata properly
stores tuple labels. Fixes rdar://problem/23130016.

Author: DougGregor

stdlib/public/core/OutputStream.swift

@@ -270,16 +270,24 @@ internal func _adHocPrint_unlocked<T, TargetStream : TextOutputStream>(
       case .tuple:
         target.write("(")
         var first = true
-        for (_, value) in mirror.children {
+        for (label, value) in mirror.children {
           if first {
             first = false
           } else {
             target.write(", ")
           }
+
+          if let label = label {
+            if !label.isEmpty && label[label.startIndex] != "." {
+              target.write(label)
+              target.write(": ")
+            }
+          }
+
           _debugPrint_unlocked(value, &target)
         }
         target.write(")")
-      case .`struct`:
+      case .struct:
         printTypeName(mirror.subjectType)
         target.write("(")
         var first = true
@@ -296,7 +304,7 @@ internal func _adHocPrint_unlocked<T, TargetStream : TextOutputStream>(
           }
         }
         target.write(")")
-      case .`enum`:
+      case .enum:
         if let cString = _getEnumCaseName(value),
             let caseName = String(validatingUTF8: cString) {
           // Write the qualified type name in debugPrint.

test/Interpreter/tuple_casts.swift

@@ -15,16 +15,21 @@ func anyToInt2(_ x: Any) -> (Int, Int) {
   return x as! (Int, Int)
 }
 
+func anyToPartlyLabeled(_ x: Any) -> (first: Int, Int, third: Int) {
+  return x as! (first: Int, Int, third: Int)
+}
+
 // Labels can be added/removed.
-print("Label add/remove")          // CHECK: Label add/remove
-print(anyToIntPoint((x: 1, y: 2))) // CHECK-NEXT: (1, 2)
-print(anyToIntPoint((3, 4)))       // CHECK-NEXT: (3, 4)
-print(anyToIntPoint((x: 5, 6)))    // CHECK-NEXT: (5, 6)
-print(anyToInt2((1, 2)))           // CHECK-NEXT: (1, 2)
-print(anyToInt2((x: 3, y: 4)))     // CHECK-NEXT: (3, 4)
-print(anyToInt2((x: 5, 6)))        // CHECK-NEXT: (5, 6)
+print("Label add/remove")            // CHECK: Label add/remove
+print(anyToIntPoint((x: 1, y: 2)))   // CHECK-NEXT: (x: 1, y: 2)
+print(anyToIntPoint((3, 4)))         // CHECK-NEXT: (x: 3, y: 4)
+print(anyToIntPoint((x: 5, 6)))      // CHECK-NEXT: (x: 5, y: 6)
+print(anyToInt2((1, 2)))             // CHECK-NEXT: (1, 2)
+print(anyToInt2((x: 3, y: 4)))       // CHECK-NEXT: (3, 4)
+print(anyToInt2((x: 5, 6)))          // CHECK-NEXT: (5, 6)
+print(anyToPartlyLabeled((1, 2, 3))) // CHECK-NEXT: (first: 1, 2, third: 3)
 
 // Labels cannot be wrong.
 print("Wrong labels")                 // CHECK: Wrong labels
 print(anyToIntPointOpt((x: 1, z: 2))) // CHECK-NEXT: nil
-print(anyToIntPointOpt((x: 1, y: 2))) // CHECK-NEXT: Optional((1, 2))
+print(anyToIntPointOpt((x: 1, y: 2))) // CHECK-NEXT: Optional((x: 1, y: 2))

test/stdlib/ReflectionHashing.swift

@@ -40,38 +40,38 @@ Reflection.test("Dictionary") {
   var expected = ""
   expected += "▿ 5 key/value pairs\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Four\"\n"
-  expected += "    - .1: 4\n"
+  expected += "    - key: \"Four\"\n"
+  expected += "    - value: 4\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"One\"\n"
-  expected += "    - .1: 1\n"
+  expected += "    - key: \"One\"\n"
+  expected += "    - value: 1\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Two\"\n"
-  expected += "    - .1: 2\n"
+  expected += "    - key: \"Two\"\n"
+  expected += "    - value: 2\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Five\"\n"
-  expected += "    - .1: 5\n"
+  expected += "    - key: \"Five\"\n"
+  expected += "    - value: 5\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Three\"\n"
-  expected += "    - .1: 3\n"
+  expected += "    - key: \"Three\"\n"
+  expected += "    - value: 3\n"
 #elseif arch(x86_64) || arch(arm64) || arch(powerpc64) || arch(powerpc64le) || arch(s390x)
   var expected = ""
   expected += "▿ 5 key/value pairs\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Three\"\n"
-  expected += "    - .1: 3\n"
+  expected += "    - key: \"Three\"\n"
+  expected += "    - value: 3\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Two\"\n"
-  expected += "    - .1: 2\n"
+  expected += "    - key: \"Two\"\n"
+  expected += "    - value: 2\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Four\"\n"
-  expected += "    - .1: 4\n"
+  expected += "    - key: \"Four\"\n"
+  expected += "    - value: 4\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"One\"\n"
-  expected += "    - .1: 1\n"
+  expected += "    - key: \"One\"\n"
+  expected += "    - value: 1\n"
   expected += "  ▿ (2 elements)\n"
-  expected += "    - .0: \"Five\"\n"
-  expected += "    - .1: 5\n"
+  expected += "    - key: \"Five\"\n"
+  expected += "    - value: 5\n"
 #else
   fatalError("unimplemented")
 #endif

test/stdlib/Runtime.swift.gyb

@@ -907,8 +907,8 @@ Reflection.test("Enum/IndirectGeneric/DefaultMirror") {
   expectEqual("\(y)", "Bar(\"twenty-two\")")
 
   let list = List.Cons(first: 0, rest: .Cons(first: 1, rest: .Nil))
-  expectEqual("\(list)",
-              "Cons(0, a.List<Swift.Int>.Cons(1, a.List<Swift.Int>.Nil))")
+  expectEqual("Cons(first: 0, rest: a.List<Swift.Int>.Cons(first: 1, rest: a.List<Swift.Int>.Nil))",
+	      "\(list)")
 }
 
 class Brilliant : CustomReflectable {