[noescape by default] Emit deprecation warning/fixit for @NoEscape

@NoEscape is now the default behavior, so deprecate it and offer a
fixit.

Author: milseman

CHANGELOG.md

@@ -2,6 +2,14 @@ Note: This is in reverse chronological order, so newer entries are added to the
 
 Swift 3.0
 ---------
+
+* [SE-103](https://github.com/apple/swift-evolution/blob/master/proposals/0103-make-noescape-default.md)
+
+  Closure parameters are non-escaping by default, rather than explicitly being
+  annotated @noescape. Use @escaping to say that a closure parameter may escape.
+  @autoclosure(escaping) is now spelled @autoclosure @escaping. @noescape and
+  @autoclosure(escaping) are deprecated.
+
 * [SE-0115](https://github.com/apple/swift-evolution/blob/master/proposals/0115-literal-syntax-protocols.md)
 
   To clarify the role of `*LiteralConvertible` protocols, they have 

include/swift/AST/DiagnosticsParse.def

@@ -1219,7 +1219,7 @@ WARNING(attr_autoclosure_escaping_deprecated,none,
         "@autoclosure(escaping) is deprecated; use @autoclosure @escaping instead",
         ())
 WARNING(attr_noescape_deprecated,none,
-        "@noescape is the default and is deprecated; omit it",
+        "@noescape is the default and is deprecated",
         ())
 
 // convention

lib/AST/ASTDumper.cpp

@@ -2910,7 +2910,6 @@ namespace {
       printFlag(T->isAutoClosure(), "autoclosure");
 
       // Dump out either @noescape or @escaping
-      printFlag(T->isNoEscape(), "@noescape");
       printFlag(!T->isNoEscape(), "@escaping");
 
       printFlag(T->throws(), "throws");

lib/Parse/ParseDecl.cpp

@@ -1542,6 +1542,11 @@ bool Parser::parseTypeAttribute(TypeAttributes &Attributes, bool justChecking) {
       diagnose(Loc, diag::attr_escaping_conflicts_noescape);
       return false;
     }
+
+    // @noescape is deprecated and no longer used
+    diagnose(Loc, diag::attr_noescape_deprecated)
+      .fixItRemove({Attributes.AtLoc,Loc});
+
     break;
   case TAK_escaping:
     // You can't specify @noescape and @escaping together.

test/attr/attr_availability.swift

@@ -704,7 +704,7 @@ func closure_LU_LL(x: Int, _ y: () -> Int) {} // expected-note 2 {{here}}
 @available(*, unavailable, renamed: "after(arg:fn:)")
 func closure_LL_LL(x: Int, y: () -> Int) {} // expected-note 2 {{here}}
 @available(*, unavailable, renamed: "after(arg:fn:)")
-func closure_UU_LL_ne(_ x: Int, _ y: @noescape () -> Int) {} // expected-note 2 {{here}}
+func closure_UU_LL_ne(_ x: Int, _ y: () -> Int) {} // expected-note 2 {{here}}
 
 @available(*, unavailable, renamed: "after(arg:_:)")
 func closure_UU_LU(_ x: Int, _ closure: () -> Int) {} // expected-note 2 {{here}}
@@ -713,7 +713,7 @@ func closure_LU_LU(x: Int, _ closure: () -> Int) {} // expected-note 2 {{here}}
 @available(*, unavailable, renamed: "after(arg:_:)")
 func closure_LL_LU(x: Int, y: () -> Int) {} // expected-note 2 {{here}}
 @available(*, unavailable, renamed: "after(arg:_:)")
-func closure_UU_LU_ne(_ x: Int, _ y: @noescape () -> Int) {} // expected-note 2 {{here}}
+func closure_UU_LU_ne(_ x: Int, _ y: () -> Int) {} // expected-note 2 {{here}}
 
 func testTrailingClosure() {
   closure_U_L { 0 } // expected-error {{'closure_U_L' has been renamed to 'after(fn:)'}} {{3-14=after}} {{none}}

test/attr/attr_escaping.swift

@@ -5,6 +5,7 @@
 func wrongParamType(a: @escaping Int) {} // expected-error {{@escaping attribute only applies to function types}}
 
 func conflictingAttrs(_ fn: @noescape @escaping () -> Int) {} // expected-error {{@escaping conflicts with @noescape}}
+ // expected-warning@-1{{@noescape is the default and is deprecated}} {{29-39=}}
 
 func takesEscaping(_ fn: @escaping () -> Int) {} // ok
 
@@ -69,15 +70,4 @@ func callEscapingAutoclosureWithNoEscape_3(_ fn: @autoclosure () -> Int) {
   takesEscapingAutoclosure(fn()) // expected-error{{closure use of non-escaping parameter 'fn' may allow it to escape}}
 }
 
-func takesAutoclosure(_ fn: @autoclosure () -> Int) {}
-
-func callAutoclosureWithNoEscape(_ fn: () -> Int) {
-  takesAutoclosure(1+1) // ok
-}
-func callAutoclosureWithNoEscape_2(_ fn: () -> Int) {
-  takesAutoclosure(fn()) // ok
-}
-func callAutoclosureWithNoEscape_3(_ fn: @autoclosure () -> Int) {
-  takesAutoclosure(fn()) // ok
-}
 

test/attr/attr_noescape.swift

@@ -3,10 +3,11 @@
 @noescape var fn : () -> Int = { 4 }  // expected-error {{@noescape may only be used on 'parameter' declarations}} {{1-11=}}
 
 func conflictingAttrs(_ fn: @noescape @escaping () -> Int) {} // expected-error {{@escaping conflicts with @noescape}}
+ // expected-warning@-1{{@noescape is the default and is deprecated}} {{29-39=}}
 
 func doesEscape(_ fn : @escaping () -> Int) {}
 
-func takesGenericClosure<T>(_ a : Int, _ fn : @noescape () -> T) {}
+func takesGenericClosure<T>(_ a : Int, _ fn : @noescape () -> T) {} // expected-warning{{@noescape is the default and is deprecated}} {{47-57=}}
 
 
 func takesNoEscapeClosure(_ fn : () -> Int) {
@@ -161,9 +162,9 @@ class SomeClass {
 
 
 // Implicit conversions (in this case to @convention(block)) are ok.
-@_silgen_name("whatever")
-func takeNoEscapeAsObjCBlock(_: @noescape @convention(block) () -> Void)
-func takeNoEscapeTest2(_ fn : @noescape () -> ()) {
+@_silgen_name("whatever") 
+func takeNoEscapeAsObjCBlock(_: @noescape @convention(block) () -> Void)  // expected-warning{{@noescape is the default and is deprecated}} {{33-43=}}
+func takeNoEscapeTest2(_ fn : @noescape () -> ()) {  // expected-warning{{@noescape is the default and is deprecated}} {{31-41=}}
   takeNoEscapeAsObjCBlock(fn)
 }
 
@@ -177,6 +178,7 @@ func testAutoclosure(_ a : @autoclosure () -> Int) { // expected-note{{parameter
 // <rdar://problem/19470858> QoI: @autoclosure implies @noescape, so you shouldn't be allowed to specify both
 func redundant(_ fn : @noescape  // expected-error @+1 {{@noescape is implied by @autoclosure and should not be redundantly specified}}
                @autoclosure () -> Int) {
+ // expected-warning@-2{{@noescape is the default and is deprecated}} {{23-33=}}
 }
 
 
@@ -193,7 +195,7 @@ func overloadedEach<P: P2, T>(_ source: P, _ transform: @escaping (P.Element) ->
 
 struct S : P2 {
   typealias Element = Int
-  func each(_ transform: @noescape (Int) -> ()) {
+  func each(_ transform: @noescape (Int) -> ()) { // expected-warning{{@noescape is the default and is deprecated}} {{26-36=}}
     overloadedEach(self,  // expected-error {{cannot invoke 'overloadedEach' with an argument list of type '(S, (Int) -> (), Int)'}}
                    transform, 1)
     // expected-note @-2 {{overloads for 'overloadedEach' exist with these partially matching parameter lists: (O, (O.Element) -> (), T), (P, (P.Element) -> (), T)}}
@@ -203,17 +205,18 @@ struct S : P2 {
 
 
 // rdar://19763676 - False positive in @noescape analysis triggered by parameter label
-func r19763676Callee(_ f: @noescape (_ param: Int) -> Int) {}
+func r19763676Callee(_ f: @noescape (_ param: Int) -> Int) {} // expected-warning{{@noescape is the default and is deprecated}} {{27-37=}}
 
-func r19763676Caller(_ g: @noescape (Int) -> Int) {
+func r19763676Caller(_ g: @noescape (Int) -> Int) { // expected-warning{{@noescape is the default and is deprecated}} {{27-37=}}
   r19763676Callee({ _ in g(1) })
 }
 
 
 // <rdar://problem/19763732> False positive in @noescape analysis triggered by default arguments
 func calleeWithDefaultParameters(_ f: @noescape () -> (), x : Int = 1) {}  // expected-warning {{closure parameter prior to parameters with default arguments will not be treated as a trailing closure}}
+  // expected-warning@-1{{@noescape is the default and is deprecated}} {{39-49=}}
 
-func callerOfDefaultParams(_ g: @noescape () -> ()) {
+func callerOfDefaultParams(_ g: @noescape () -> ()) { // expected-warning{{@noescape is the default and is deprecated}} {{33-43=}}
   calleeWithDefaultParameters(g)
 }
 
@@ -241,20 +244,20 @@ public func XCTAssert(_ expression: @autoclosure () -> Bool, _ message: String =
 
 
 /// SR-770 - Currying and `noescape`/`rethrows` don't work together anymore
-func curriedFlatMap<A, B>(_ x: [A]) -> (@noescape (A) -> [B]) -> [B] {
+func curriedFlatMap<A, B>(_ x: [A]) -> (@noescape (A) -> [B]) -> [B] { // expected-warning{{@noescape is the default and is deprecated}} {{41-50=}}
   return { f in
     x.flatMap(f)
   }
 }
 
-func curriedFlatMap2<A, B>(_ x: [A]) -> (@noescape (A) -> [B]) -> [B] {
-  return { (f : @noescape (A) -> [B]) in
+func curriedFlatMap2<A, B>(_ x: [A]) -> (@noescape (A) -> [B]) -> [B] { // expected-warning{{@noescape is the default and is deprecated}} {{42-51=}}
+  return { (f : @noescape (A) -> [B]) in // expected-warning{{@noescape is the default and is deprecated}} {{17-27=}}
     x.flatMap(f)
   }
 }
 
 func bad(_ a : @escaping (Int)-> Int) -> Int { return 42 }
-func escapeNoEscapeResult(_ x: [Int]) -> (@noescape (Int) -> Int) -> Int {
+func escapeNoEscapeResult(_ x: [Int]) -> (@noescape (Int) -> Int) -> Int { // expected-warning{{@noescape is the default and is deprecated}} {{43-52=}}
   return { f in // expected-note{{parameter 'f' is implicitly non-escaping}}
     bad(f)  // expected-error {{passing non-escaping parameter 'f' to function expecting an @escaping closure}}
   }
@@ -263,7 +266,7 @@ func escapeNoEscapeResult(_ x: [Int]) -> (@noescape (Int) -> Int) -> Int {
 
 // SR-824 - @noescape for Type Aliased Closures
 //
-typealias CompletionHandlerNE = @noescape (_ success: Bool) -> ()
+typealias CompletionHandlerNE = @noescape (_ success: Bool) -> () // expected-warning{{@noescape is the default and is deprecated}} {{33-43=}}
 typealias CompletionHandler = (_ success: Bool) -> ()
 var escape : CompletionHandlerNE
 func doThing1(_ completion: (_ success: Bool) -> ()) {
@@ -280,7 +283,10 @@ func doThing2(_ completion: CompletionHandlerNE) {
 }
 
 // <rdar://problem/19997680> @noescape doesn't work on parameters of function type
-func apply<T, U>(_ f: @noescape (T) -> U, g: @noescape (@noescape (T) -> U) -> U) -> U {
+func apply<T, U>(_ f: @noescape (T) -> U, g: @noescape (@noescape (T) -> U) -> U) -> U { 
+  // expected-warning@-1{{@noescape is the default and is deprecated}} {{23-33=}}
+  // expected-warning@-2{{@noescape is the default and is deprecated}} {{46-56=}}
+  // expected-warning@-3{{@noescape is the default and is deprecated}} {{57-66=}}
   return g(f)
 }
 
@@ -290,8 +296,8 @@ enum r19997577Type {
   case Function(() -> r19997577Type, () -> r19997577Type)
   case Sum(() -> r19997577Type, () -> r19997577Type)
 
-  func reduce<Result>(_ initial: Result, _ combine: @noescape (Result, r19997577Type) -> Result) -> Result {
-    let binary: @noescape (r19997577Type, r19997577Type) -> Result = { combine(combine(combine(initial, self), $0), $1) }
+  func reduce<Result>(_ initial: Result, _ combine: @noescape (Result, r19997577Type) -> Result) -> Result { // expected-warning{{@noescape is the default and is deprecated}} {{53-63=}}
+    let binary: @noescape (r19997577Type, r19997577Type) -> Result = { combine(combine(combine(initial, self), $0), $1) } // expected-warning{{@noescape is the default and is deprecated}} {{17-27=}}
     switch self {
     case .Unit:
       return combine(initial, self)
@@ -305,9 +311,13 @@ enum r19997577Type {
 
 // type attribute and decl attribute
 func noescapeD(@noescape f: @escaping () -> Bool) {} // expected-error {{@noescape is now an attribute on a parameter type, instead of on the parameter itself}} {{16-25=}} {{29-29=@noescape }}
-func noescapeT(f: @noescape () -> Bool) {} // ok
+func noescapeT(f: @noescape () -> Bool) {} // expected-warning{{@noescape is the default and is deprecated}} {{19-29=}}
 func autoclosureD(@autoclosure f: () -> Bool) {} // expected-error {{@autoclosure is now an attribute on a parameter type, instead of on the parameter itself}} {{19-31=}} {{35-35=@autoclosure }}
 func autoclosureT(f: @autoclosure () -> Bool) {}  // ok
 
 func noescapeD_noescapeT(@noescape f: @noescape () -> Bool) {} // expected-error {{@noescape is now an attribute on a parameter type, instead of on the parameter itself}}
+ // expected-warning@-1{{@noescape is the default and is deprecated}} {{39-49=}}
+
 func autoclosureD_noescapeT(@autoclosure f: @noescape () -> Bool) {} // expected-error {{@autoclosure is now an attribute on a parameter type, instead of on the parameter itself}} {{29-41=}} {{45-45=@autoclosure }}
+ // expected-warning@-1{{@noescape is the default and is deprecated}} {{45-55=}}
+