Roadmap for improving the type checker

Development Compiler
9

I don’t know if it’s related to result builder but yesterday I had a The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions in a SwiftUI view that was quite difficult to catch. Here’s a minimal reproduction:

struct ContentView: View {
        
    @State var selection = ""
    
    @State var a: Int?
    @State var b: Int?
    @State var c: Int?
        
    var body: some View { // ❌ The compiler is unable to type-check this expression in reasonable time; try breaking up the expression into distinct sub-expressions
        ScrollView {
            VStack {
                Picker(selection: $selection) {
                    ForEach(["a", "b", "c"], id: \.self) {
                        Text($0)
                            .foregroundStyl(.red) // Typo Here
                    }
                } label: {
                    
                }
                .pickerStyle(.segmented)
            }
            .padding(.horizontal)
        }
        .onChange(of: a) { oldValue, newValue in
            
        }
        .onChange(of: b) { oldValue, newValue in
            
        }
        .onChange(of: c) { oldValue, newValue in
            
        }
    }

}

Subtle changes such as commenting one onChange(of:), pickerStyle(.segmented) and padding(.horizontal) lead to the correct Value of type 'Text' has no member 'foregroundStyl' diagnostic.

Xcode Version 26.0.1 (17A400)

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