[SR-8814] GenericSignatureBuilder should re-introduce conformance requirements when adding a superclass requirement #51322
Comments
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Can you share the project? If not publicly here, possibly just with Apple via https://bugreport.apple.com? @eeckstein, does this look familiar? |
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No. |
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Comment by Lukas Foldyna (JIRA) import UIKit
protocol TableRowID {
init?(rawValue: Int)
var rawValue: Int { get }
var order: Int { get }
}
extension TableRowID {
var order: Int {
return rawValue
}
}
protocol TableRow {
static var identifiers: [String] { get }
var identifier: String { get }
var height: CGFloat { get }
var estimatedHeight: CGFloat { get }
}
extension TableRow {
var identifier: String {
return Self.identifiers.first ?? ""
}
var estimatedHeight: CGFloat {
return height
}
}
protocol InputViewCell {
var id: TableRowID { get }
var inputResponder: UIResponder? { get }
func setup(row: TableRow, id: TableRowID, delegate: Any)
}
protocol TableSectioning: MutableCollection {
associatedtype ID: TableRowID & Hashable
var rows: [ID: TableRow] { get }
func row(at index: Int) -> TableRow?
}
struct TableSection<ID>: TableSectioning where ID: TableRowID & Hashable {
typealias DictionaryType = [ID: TableRow]
internal(set) var rows: DictionaryType
internal var orderIndex: [Int: ID] = [:]
init(rows: DictionaryType = [:]) {
self.rows = rows
rows.keys.forEach { orderIndex[$0.order] = $0 }
}
func row(at index: Int) -> TableRow? {
guard let id = orderIndex[index] else { return nil }
return rows[id]
}
// MARK: - Collection
typealias Index = DictionaryType.Index
typealias Element = DictionaryType.Element
var startIndex: Index { return rows.startIndex }
var endIndex: Index { return rows.endIndex }
subscript(index: Index) -> DictionaryType.Iterator.Element {
get {
return rows[index]
}
set {
rows[newValue.key] = newValue.value
orderIndex[newValue.key.order] = newValue.key
}
}
public subscript(key: DictionaryType.Key) -> DictionaryType.Value? {
get {
return rows[key]
}
set {
rows[key] = newValue
orderIndex[key.order] = key
}
}
func index(after i: DictionaryType.Index) -> DictionaryType.Index {
return rows.index(after: i)
}
// MARK: - Sequence
typealias Iterator = AnyIterator<(key: ID, value: TableRow)>
func makeIterator() -> Iterator {
var iterator = rows.makeIterator()
return AnyIterator {
return iterator.next()
}
}
}
protocol TableViewModel {
associatedtype Sectioning: TableSectioning
var sections: [Sectioning] { get }
}
extension TableViewModel {
func tableRow(for indexPath: IndexPath) -> TableRow? {
return sections[indexPath.section].row(at: indexPath.row)
}
}
protocol InputRow: class, TableRow {
typealias InputValue = AnyObject
var value: InputValue? { get set }
var isValid: Bool { get }
}
protocol TextInputRow: InputRow {
var title: String { get set }
var text: String? { get set }
}
extension TextInputRow {
var value: Self.InputValue? {
get {
return text as Self.InputValue
}
set {
text = newValue as? String
}
}
var isTextInLimit: Bool {
return true
}
}
protocol BaseFormViewModel: TableViewModel where ID: TableRowID & Hashable {
associatedtype ID
typealias Values = [ID: InputRow.InputValue]
func id(at indexPath: IndexPath) -> ID?
func indexPath(with id: ID) -> IndexPath?
func inputValue(with id: ID) -> InputRow.InputValue?
var indexPathForFirstInputRow: IndexPath? { get }
}
extension BaseFormViewModel {
func inputRow(with id: Self.Sectioning.ID) -> InputRow? {
for section in sections {
guard let row = section.rows[id] as? InputRow else { continue }
return row
}
return nil
}
func inputValue(with id: Self.Sectioning.ID) -> InputRow.InputValue? {
return inputRow(with: id)?.value
}
var indexPathForFirstInputRow: IndexPath? {
var sectionIndex = 0
for section in sections {
for index in 0..<section.count {
guard let _ = section.row(at: index) as? TextInputRow else { continue }
return IndexPath(row: index, section: sectionIndex)
}
sectionIndex += 1
}
return nil
}
}
class DefaultFormViewModel<I>: BaseFormViewModel where I: TableRowID & Hashable {
typealias ID = I
typealias Sectioning = TableSection<ID>
internal(set) var sections: [Sectioning] = [] {
didSet {
setupIndex()
}
}
private(set) var inputIndex: [ID: IndexPath] = [:]
private(set) var pathIndex: [IndexPath: ID] = [:]
func setupIndex() {
inputIndex.removeAll()
pathIndex.removeAll()
var sectionIndex = 0
for section in sections {
for index in 0..<section.count {
guard let key = section.orderIndex[index] else { continue }
let indexPath = IndexPath(row: index, section: sectionIndex)
inputIndex[key] = indexPath
pathIndex[indexPath] = key
}
sectionIndex += 1
}
}
func inputValue(with id: ID) -> InputRow.InputValue? {
return inputRow(with: id)?.value
}
func id(at indexPath: IndexPath) -> ID? {
return pathIndex[indexPath]
}
func indexPath(with id: ID) -> IndexPath? {
return inputIndex[id]
}
}
class BaseFormVC<VM: BaseFormViewModel>: UIViewController, UITextViewDelegate, UITextFieldDelegate {
private var formSentIndicator: Bool = false
weak var tableView: UITableView!
// MARK: - Model
internal var viewModel: VM?
// MARK: - First responder
internal func makeFirstInputFirstResponder() {
guard let indexPath = viewModel?.indexPathForFirstInputRow,
let cell = tableView.cellForRow(at: indexPath) else { return }
if let cell = cell as? InputViewCell {
cell.inputResponder?.becomeFirstResponder()
}
}
internal func makeInputFirstResponder(with id: VM.ID) {
guard !formSentIndicator,
let indexPath = viewModel?.indexPath(with: id) else { return }
if let cell = tableView.cellForRow(at: indexPath) as? InputViewCell {
cell.inputResponder?.becomeFirstResponder()
} else {
tableView.scrollToRow(at: indexPath, at: .top, animated: true)
DispatchQueue.main.asyncAfter(deadline: .now() + 0.3) {
if let cell = self.tableView.cellForRow(at: indexPath) as? InputViewCell {
cell.inputResponder?.becomeFirstResponder()
}
}
}
}
}
struct Payment {
var amount: Double
var message: String
}
protocol NewPaymentVM: BaseFormViewModel {
associatedtype Value = Payment
var payment: Value { get }
}
protocol PaymentController where Self: UIViewController {
var payment: Payment? { get set }
}
class NewPaymentVC<RPVM>: BaseFormVC<RPVM>, PaymentController where RPVM: NewPaymentVM {
var payment: Payment? = nil {
didSet {
setupViewModel()
}
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
makeFirstInputFirstResponder()
}
internal func setupViewModel() {
}
}
enum NewDirectDebitInputType: Int, TableRowID {
case amount
case message
}
class NewDirectDebitPaymentVM: DefaultFormViewModel<NewDirectDebitInputType>, NewPaymentVM {
var payment: Payment
init(payment: Payment) {
self.payment = payment
super.init()
}
}
class NewDirectDebitPaymentVC: NewPaymentVC<NewDirectDebitPaymentVM> {
override func setupViewModel() {
guard let payment = payment else { return }
let viewModel = NewDirectDebitPaymentVM(payment: payment)
self.viewModel = viewModel
}
internal override func makeFirstInputFirstResponder() {
if let limit = viewModel?.inputValue(with: .amount) as? Double, limit > 0 {
makeInputFirstResponder(with: .message)
} else {
super.makeFirstInputFirstResponder()
}
}
} |
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Thanks! I can reproduce the crash. |
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@swift-ci create |
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Reduced test case: If you run it with -emit-silgen you'll see that the 'T : Hashable' requirement is incorrectly dropped from the protocol witness thunk's generic signature. |
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So I made a bit of progress, but it’s still a mystery. My latest test case requires this setup: Here is the bad case I’ve been looking at: Here, T and U.T are in the same equivalence class. The conformance U : P has two sources:
The second one responds with true to isDerivedRequirement(), so it becomes the best one, so it gets dropped. Now this version of foo() works — but for the wrong reason: When we add same-type requirements between a type parameter and a concrete type, we make sure to concretize any nested types in concretizeNestedTypeFromConcreteParent(). However, we don’t do anything of the sort when adding a superclass constraint. So in the above case, T and U.T are different equivalence classes. T : Q does not have a derived source, so we retain it in the minimized signature. However U.T is redundant for the same reason as above. I suspect not concretizing nested types that already exist when a superclass constraint is added is causing us other problems elsewhere, too. |
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Comment by Jonathan (JIRA) @belkadan I don't know enough about the compiler to know if this is actually a duplicate of https://bugs.swift.org/browse/SR-10182, but SR-10182 didn't cause a crash in Swift 4/Xcode 10, only in Xcode 10.2, unlike this ticket, so not sure it should be marked as a duplicate? Also it is still causing a segmentation fault in the Xcode 11 beta. |
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My repro from SR-11913 (which Slava duped here): public protocol Something {
associatedtype McGuffin: BinaryInteger
func whatever() throws -> [String]
}
extension Something {
func whatever() throws -> [String] { [] }
}
class Thing<McGuffin: BinaryInteger>: Something {}Still happens in 11.3 |
AnthonyLatsis
added
the
crash
Environment
Xcode (10A255), macOS 10.13.6 (17G2307)
Additional Detail from JIRA
md5: 3ceba1c7e1776ae34423d56b0b58a883
is duplicated by:
relates to:
Issue Description:
Our app is failing to archive in new Xcode 10 and Swift 4. (-0)
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