[AST/Printing] Don't omit empty labels in special names

This makes diagnostics more verbose and accurate, because
it's possible to distinguish how many parameters there are
based on the message itself.

Also there are multiple diagnostic messages in a format of
`<descriptive-kind> <decl-name> ...` that get printed as
e.g. `subscript 'subscript'` if empty labels are omitted.

Author: xedin

lib/AST/Identifier.cpp

@@ -184,7 +184,7 @@ llvm::raw_ostream &DeclName::print(llvm::raw_ostream &os,
 }
 
 llvm::raw_ostream &DeclName::printPretty(llvm::raw_ostream &os) const {
-  return print(os, /*skipEmptyArgumentNames=*/true);
+  return print(os, /*skipEmptyArgumentNames=*/!isSpecial());
 }
 
 ObjCSelector::ObjCSelector(ASTContext &ctx, unsigned numArgs,

test/ClangImporter/availability.swift

@@ -54,19 +54,19 @@ func test_unavailable_accessors(_ obj: UnavailableAccessors,
   UnavailableAccessors.setterUnavailableClass = 0 // expected-error {{setter for 'setterUnavailableClass' is unavailable}}
   UnavailableAccessors.setterUnavailableClass += 1 // expected-error {{setter for 'setterUnavailableClass' is unavailable}}
 
-  _ = sub[0] // expected-error {{getter for 'subscript' is unavailable: bad subscript getter}}
-  sub[0] = "" // expected-error {{setter for 'subscript' is unavailable: bad subscript setter}}
-  sub[0] += "" // expected-error {{getter for 'subscript' is unavailable: bad subscript getter}} expected-error {{setter for 'subscript' is unavailable: bad subscript setter}}
+  _ = sub[0] // expected-error {{getter for 'subscript(_:)' is unavailable: bad subscript getter}}
+  sub[0] = "" // expected-error {{setter for 'subscript(_:)' is unavailable: bad subscript setter}}
+  sub[0] += "" // expected-error {{getter for 'subscript(_:)' is unavailable: bad subscript getter}} expected-error {{setter for 'subscript(_:)' is unavailable: bad subscript setter}}
 
-  _ = subGetter[0] // expected-error {{getter for 'subscript' is unavailable: bad subscript getter}}
+  _ = subGetter[0] // expected-error {{getter for 'subscript(_:)' is unavailable: bad subscript getter}}
   subGetter[0] = ""
-  subGetter[0] += "" // expected-error {{getter for 'subscript' is unavailable: bad subscript getter}}
+  subGetter[0] += "" // expected-error {{getter for 'subscript(_:)' is unavailable: bad subscript getter}}
 
   _ = subSetter[0]
-  subSetter[0] = "" // expected-error {{setter for 'subscript' is unavailable: bad subscript setter}}
-  subSetter[0] += "" // expected-error {{setter for 'subscript' is unavailable: bad subscript setter}}
+  subSetter[0] = "" // expected-error {{setter for 'subscript(_:)' is unavailable: bad subscript setter}}
+  subSetter[0] += "" // expected-error {{setter for 'subscript(_:)' is unavailable: bad subscript setter}}
 
-  _ = subReadOnly[0] // expected-error {{getter for 'subscript' is unavailable}}
+  _ = subReadOnly[0] // expected-error {{getter for 'subscript(_:)' is unavailable}}
 }
 
 func test_deprecated(_ s:UnsafeMutablePointer<CChar>, _ obj: AccessorDeprecations,
@@ -100,19 +100,19 @@ func test_deprecated(_ s:UnsafeMutablePointer<CChar>, _ obj: AccessorDeprecation
   AccessorDeprecations.setterDeprecatedClass = 0 // expected-warning {{setter for 'setterDeprecatedClass' is deprecated}}
   AccessorDeprecations.setterDeprecatedClass += 1 // expected-warning {{setter for 'setterDeprecatedClass' is deprecated}}
 
-  _ = sub[0] // expected-warning {{getter for 'subscript' is deprecated: bad subscript getter}}
-  sub[0] = "" // expected-warning {{setter for 'subscript' is deprecated: bad subscript setter}}
-  sub[0] += "" // expected-warning {{getter for 'subscript' is deprecated: bad subscript getter}} expected-warning {{setter for 'subscript' is deprecated: bad subscript setter}}
+  _ = sub[0] // expected-warning {{getter for 'subscript(_:)' is deprecated: bad subscript getter}}
+  sub[0] = "" // expected-warning {{setter for 'subscript(_:)' is deprecated: bad subscript setter}}
+  sub[0] += "" // expected-warning {{getter for 'subscript(_:)' is deprecated: bad subscript getter}} expected-warning {{setter for 'subscript(_:)' is deprecated: bad subscript setter}}
 
-  _ = subGetter[0] // expected-warning {{getter for 'subscript' is deprecated: bad subscript getter}}
+  _ = subGetter[0] // expected-warning {{getter for 'subscript(_:)' is deprecated: bad subscript getter}}
   subGetter[0] = ""
-  subGetter[0] += "" // expected-warning {{getter for 'subscript' is deprecated: bad subscript getter}}
+  subGetter[0] += "" // expected-warning {{getter for 'subscript(_:)' is deprecated: bad subscript getter}}
 
   _ = subSetter[0]
-  subSetter[0] = "" // expected-warning {{setter for 'subscript' is deprecated: bad subscript setter}}
-  subSetter[0] += "" // expected-warning {{setter for 'subscript' is deprecated: bad subscript setter}}
+  subSetter[0] = "" // expected-warning {{setter for 'subscript(_:)' is deprecated: bad subscript setter}}
+  subSetter[0] += "" // expected-warning {{setter for 'subscript(_:)' is deprecated: bad subscript setter}}
 
-  _ = subReadOnly[0] // expected-warning {{getter for 'subscript' is deprecated}}
+  _ = subReadOnly[0] // expected-warning {{getter for 'subscript(_:)' is deprecated}}
 }
 
 func test_NSInvocation(_ x: NSInvocation,         // expected-error {{'NSInvocation' is unavailable}}

test/Compatibility/attr_override.swift

@@ -40,7 +40,7 @@ class A {
   var v9: Int { return 5 } // expected-note{{attempt to override property here}}
   var v10: Int { return 5 } // expected-note{{attempt to override property here}}
 
-  subscript (i: Int) -> String { // expected-note{{potential overridden subscript 'subscript' here}}
+  subscript (i: Int) -> String { // expected-note{{potential overridden subscript 'subscript(_:)' here}}
     get {
       return "hello"
     }
@@ -49,7 +49,7 @@ class A {
     }
   }
 
-  subscript (d: Double) -> String { // expected-note{{overridden declaration is here}} expected-note{{potential overridden subscript 'subscript' here}}
+  subscript (d: Double) -> String { // expected-note{{overridden declaration is here}} expected-note{{potential overridden subscript 'subscript(_:)' here}}
     get {
       return "hello"
     }
@@ -58,11 +58,11 @@ class A {
     }
   }
 
-  subscript (i: Int8) -> A { // expected-note{{potential overridden subscript 'subscript' here}}
+  subscript (i: Int8) -> A { // expected-note{{potential overridden subscript 'subscript(_:)' here}}
     get { return self }
   }
 
-  subscript (i: Int16) -> A { // expected-note{{attempt to override subscript here}} expected-note{{potential overridden subscript 'subscript' here}}
+  subscript (i: Int16) -> A { // expected-note{{attempt to override subscript here}} expected-note{{potential overridden subscript 'subscript(_:)' here}}
     get { return self }
     set { }
   }

test/Compatibility/special_func_name.swift

@@ -14,7 +14,7 @@ struct S12 : P1 { // expected-error {{type 'S12' does not conform to protocol 'P
 }
 
 protocol P2 {
-  init(_: Int) // expected-note {{protocol requires initializer 'init' with type 'Int'; do you want to add a stub?}}
+  init(_: Int) // expected-note {{protocol requires initializer 'init(_:)' with type 'Int'; do you want to add a stub?}}
 }
 
 struct S21 : P2 { // expected-error {{type 'S21' does not conform to protocol 'P2'}}

test/Compatibility/tuple_arguments_4.swift

@@ -513,7 +513,7 @@ do {
 }
 
 struct InitTwo {
-  init(_ x: Int, _ y: Int) {} // expected-note 5 {{'init' declared here}}
+  init(_ x: Int, _ y: Int) {} // expected-note 5 {{'init(_:_:)' declared here}}
 }
 
 struct InitTuple {
@@ -564,7 +564,7 @@ do {
 }
 
 struct SubscriptTwo {
-  subscript(_ x: Int, _ y: Int) -> Int { get { return 0 } set { } } // expected-note 5 {{'subscript' declared here}}
+  subscript(_ x: Int, _ y: Int) -> Int { get { return 0 } set { } } // expected-note 5 {{'subscript(_:_:)' declared here}}
 }
 
 struct SubscriptTuple {
@@ -915,7 +915,7 @@ struct GenericInitLabeled<T> {
 }
 
 struct GenericInitTwo<T> {
-  init(_ x: T, _ y: T) {} // expected-note 10 {{'init' declared here}}
+  init(_ x: T, _ y: T) {} // expected-note 10 {{'init(_:_:)' declared here}}
 }
 
 struct GenericInitTuple<T> {
@@ -1041,7 +1041,7 @@ struct GenericSubscriptLabeled<T> {
 }
 
 struct GenericSubscriptTwo<T> {
-  subscript(_ x: T, _ y: T) -> Int { get { return 0 } set { } } // expected-note 5 {{'subscript' declared here}}
+  subscript(_ x: T, _ y: T) -> Int { get { return 0 } set { } } // expected-note 5 {{'subscript(_:_:)' declared here}}
 }
 
 struct GenericSubscriptLabeledTuple<T> {

test/Constraints/diag_ambiguities.swift

@@ -27,7 +27,7 @@ func g(_ x: Int, _ y: Int) -> () {} // expected-note{{found this candidate}}
 C(g) // expected-error{{ambiguous use of 'g'}}
 
 func h<T>(_ x: T) -> () {}
-C(h) // expected-error{{ambiguous use of 'init'}}
+C(h) // expected-error{{ambiguous use of 'init(_:)'}}
 
 func rdar29691909_callee(_ o: AnyObject?) -> Any? { return o } // expected-note {{found this candidate}}
 func rdar29691909_callee(_ o: AnyObject) -> Any { return o } // expected-note {{found this candidate}}

test/Constraints/diagnostics.swift

@@ -681,7 +681,7 @@ func r23641896() {
   var g = "Hello World"
   g.replaceSubrange(0...2, with: "ce")  // expected-error {{cannot convert value of type 'ClosedRange<Int>' to expected argument type 'Range<String.Index>'}}
 
-  _ = g[12]  // expected-error {{'subscript' is unavailable: cannot subscript String with an Int, see the documentation comment for discussion}}
+  _ = g[12]  // expected-error {{'subscript(_:)' is unavailable: cannot subscript String with an Int, see the documentation comment for discussion}}
 
 }
 
@@ -1199,7 +1199,7 @@ func platypus<T>(a: [T]) {
 func badTypes() {
   let sequence:AnySequence<[Int]> = AnySequence() { AnyIterator() { [3] }}
   let array = [Int](sequence)
-  // expected-error@-1 {{initializer 'init' requires the types 'Int' and '[Int]' be equivalent}}
+  // expected-error@-1 {{initializer 'init(_:)' requires the types 'Int' and '[Int]' be equivalent}}
 }
 
 // rdar://34357545

test/Constraints/generics.swift

@@ -253,7 +253,7 @@ struct V27515965 {
 
 func test(x: S27515965) -> V27515965 {
   return V27515965(x)
-  // expected-error@-1 {{initializer 'init' requires the types 'Any' and 'Float' be equivalent}}
+  // expected-error@-1 {{initializer 'init(_:)' requires the types 'Any' and 'Float' be equivalent}}
 }
 
 protocol BaseProto {}

test/Constraints/lvalues.swift

@@ -233,7 +233,7 @@ r23331567 { $0 += 1 }
 // <rdar://problem/30685195> Compiler crash with invalid assignment
 struct G<T> {
   subscript(x: Int) -> T { get { } nonmutating set { } }
-  // expected-note@-1 {{'subscript' declared here}}
+  // expected-note@-1 {{'subscript(_:)' declared here}}
 }
 
 func wump<T>(to: T, _ body: (G<T>) -> ()) {}

test/Constraints/rdar44569159.swift

@@ -13,6 +13,6 @@ struct A {
 
 func foo(_ v: Double) {
   _ = A()[S(value: v)]
-// expected-error@-1 {{subscript 'subscript' requires that 'Double' conform to 'P'}}
+// expected-error@-1 {{subscript 'subscript(_:)' requires that 'Double' conform to 'P'}}
 // expected-error@-2 {{referencing initializer 'init(value:)' on 'S' requires that 'Double' conform to 'P'}}
 }