My watchOS app

[namename455391938-web-1]

Description

var body: some View {
   VStack {
        Text("Heart Rate")
            .fixedSize(horizontal: true, vertical: true)
            .font(.system(Font.TextStyle.headline))
            .foregroundColor(.gray)
        Text(String(format: "%d", Heart ?? Heart))
            .fixedSize(horizontal: true, vertical: true)
            .font(.system(Font.TextStyle.largeTitle))
            .foregroundColor(.red)
        Image(systemName: "heart.fill")
            .foregroundColor(.red)
   }
   .padding()
}

The var body: some View of my app is what caused the bug.

Reproduction

Text(String(format: "%d", Heart ?? Heart))

Expected behavior

Making the body variable of the View struct named ContentView.

Environment

6.0.3

Additional information

XCode made me report it.

[FrankYang0610]

According to Swift syntax, when Heart is nil, the expression on the right-hand side of the ?? operator will be used.

However, in this case, the right-hand side is still Heart, so if Heart is nil, the program crashes.

[namename455391938-web-1]

My Heart variable is not nil.
My Heart variable got set before the var body: some View part, and the variable is a HealthKit quantity type.
Please fix this.

[nate-chandler]

Please try with Xcode 26 Beta 6.

With Xcode 16.2 (Swift 6.0.3), compiling

import SwiftUI
import HealthKit

struct ContentView : View {
  var Heart : HKQuantity?
  var body: some View {
     VStack {
          Text("Heart Rate")
              .fixedSize(horizontal: true, vertical: true)
              .font(.system(Font.TextStyle.headline))
              .foregroundColor(.gray)
          Text(String(format: "%d", Heart ?? Heart))
              .fixedSize(horizontal: true, vertical: true)
              .font(.system(Font.TextStyle.largeTitle))
              .foregroundColor(.red)
          Image(systemName: "heart.fill")
              .foregroundColor(.red)
     }
     .padding()
  }
}

produces

main.swift:6:23: error: failed to produce diagnostic for expression; please submit a bug report (https://swift.org/contributing/#reporting-bugs) [failed_to_produce_diagnostic]
 4 | struct ContentView : View {
 5 |   var Heart : HKQuantity?
 6 |   var body: some View {
   |                       `- error: failed to produce diagnostic for expression; please submit a bug report (https://swift.org/contributing/#reporting-bugs) [failed_to_produce_diagnostic]
 7 |      VStack {
 8 |           Text("Heart Rate")

Compiling the same program with Xcode 26 Beta 6, however, produces

main.swift:12:46: error: value of optional type 'HKQuantity?' must be unwrapped to a value of type 'HKQuantity' [optional_not_unwrapped]
10 |               .font(.system(Font.TextStyle.headline))
11 |               .foregroundColor(.gray)
12 |           Text(String(format: "%d", Heart ?? Heart))
   |                                              |- error: value of optional type 'HKQuantity?' must be unwrapped to a value of type 'HKQuantity' [optional_not_unwrapped]
   |                                              |- note: coalesce using '??' to provide a default when the optional value contains 'nil' [unwrap_with_default_value]
   |                                              `- note: force-unwrap using '!' to abort execution if the optional value contains 'nil' [unwrap_with_force_value]
13 |               .fixedSize(horizontal: true, vertical: true)
14 |               .font(.system(Font.TextStyle.largeTitle))
make: *** [build] Error 1

So this looks to be fixed.