[Refactoring] If type has no memberwise initializable members, generate an empty initializer instead of failing

Author: ahoppen

lib/IDE/Refactoring.cpp

@@ -3160,8 +3160,6 @@ static void generateMemberwiseInit(SourceEditConsumer &EditConsumer,
                                    ArrayRef<MemberwiseParameter> memberVector,
                                    SourceLoc targetLocation) {
 
-  assert(!memberVector.empty());
-
   EditConsumer.accept(SM, targetLocation, "\ninternal init(");
   auto insertMember = [&SM](const MemberwiseParameter &memberData,
                             raw_ostream &OS, bool wantsSeparator) {
@@ -3197,13 +3195,11 @@ static void generateMemberwiseInit(SourceEditConsumer &EditConsumer,
   // Process the initial list of members, inserting commas as appropriate.
   std::string Buffer;
   llvm::raw_string_ostream OS(Buffer);
-  for (const auto &memberData : memberVector.drop_back()) {
-    insertMember(memberData, OS, /*wantsSeparator*/ true);
+  for (const auto &memberData : llvm::enumerate(memberVector)) {
+    bool wantsSeparator = (memberData.index() != memberVector.size() - 1);
+    insertMember(memberData.value(), OS, wantsSeparator);
   }
 
-  // Process the last (or perhaps, only) member.
-  insertMember(memberVector.back(), OS, /*wantsSeparator*/ false);
-
   // Synthesize the body.
   OS << ") {\n";
   for (auto &member : memberVector) {
@@ -3269,10 +3265,6 @@ collectMembersForInit(const ResolvedCursorInfo &CursorInfo,
                               varDecl->getType(), defaultInit);
   }
 
-  if (memberVector.empty()) {
-    return SourceLoc();
-  }
-  
   return targetLocation;
 }
 

test/refactoring/MemberwiseInit/Outputs/generate_memberwise/class_members.swift.expected

@@ -45,6 +45,11 @@ enum Idea {
   var subject: String { fatalError() }
 }
 
+struct OnlyComputed {
+  lazy var idea: Idea = { fatalError() }()
+  var computed: String { "hi" }
+}
+
 @propertyWrapper
 struct MyWrapper {
   let wrappedValue: String
@@ -53,3 +58,4 @@ struct MyWrapper {
 
 
 
+

test/refactoring/MemberwiseInit/Outputs/generate_memberwise/only_computed_members.swift.expected

@@ -0,0 +1,52 @@
+class Person {
+  var firstName: String!
+  var lastName: String!
+  var age: Int!
+  var planet = "Earth", solarSystem = "Milky Way"
+  var avgHeight = 175
+  let line = #line, file = #file, handle = #dsohandle
+  lazy var idea: Idea = { fatalError() }()
+  var location: () -> Place = { fatalError() }
+  var secondLocation: (() -> Place)!
+  @MyWrapper var wrapped: String = ""
+  var computed: String { "hi" }
+}
+
+struct Place {
+  typealias Callback = () -> ()
+  let person: Person
+  let street: String
+  let apartment: Optional<String>
+  let city: String
+  let state: String
+  let postalCode: Int
+  let plusFour: Int?
+  let callback: Callback
+  @MyWrapper var wrapped: String
+}
+
+protocol Thing {
+  var idea: Idea { get }
+}
+
+enum Idea {
+  var subject: String { fatalError() }
+}
+
+struct OnlyComputed {
+internal init() {
+}
+
+  lazy var idea: Idea = { fatalError() }()
+  var computed: String { "hi" }
+}
+
+@propertyWrapper
+struct MyWrapper {
+  let wrappedValue: String
+}
+
+
+
+
+

test/refactoring/MemberwiseInit/Outputs/generate_memberwise/struct_members.swift.expected

@@ -45,6 +45,11 @@ enum Idea {
   var subject: String { fatalError() }
 }
 
+struct OnlyComputed {
+  lazy var idea: Idea = { fatalError() }()
+  var computed: String { "hi" }
+}
+
 @propertyWrapper
 struct MyWrapper {
   let wrappedValue: String
@@ -53,3 +58,4 @@ struct MyWrapper {
 
 
 
+

test/refactoring/MemberwiseInit/generate_memberwise.swift

@@ -33,6 +33,11 @@ enum Idea {
   var subject: String { fatalError() }
 }
 
+struct OnlyComputed {
+  lazy var idea: Idea = { fatalError() }()
+  var computed: String { "hi" }
+}
+
 @propertyWrapper
 struct MyWrapper {
   let wrappedValue: String
@@ -45,6 +50,9 @@ struct MyWrapper {
 // RUN: %refactor -memberwise-init -source-filename %s -pos=15:8 > %t.result/struct_members.swift
 // RUN: diff -u %S/Outputs/generate_memberwise/struct_members.swift.expected %t.result/struct_members.swift
 
+// RUN: %refactor -memberwise-init -source-filename %s -pos=36:8 > %t.result/only_computed_members.swift
+// RUN: diff -u %S/Outputs/generate_memberwise/only_computed_members.swift.expected %t.result/only_computed_members.swift
+
 // RUN: not %refactor -memberwise-init -source-filename %s -pos=24:10 > %t.result/protocol_members.swift
 // RUN: not %refactor -memberwise-init -source-filename %s -pos=28:6 > %t.result/enum_members.swift