Compiler crash: error: memory read failed for 0xb3261800

Development Compiler
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1

After a very arduous process I finally got the crashing code into a reasonably minimal form:

func thisWillCauseTheCrash () {
    Task { await foo(0).run() }
}
func foo <T> (_ t: T) -> some Procedure {
    FlatMap(
        firstProcedure: AtomicProcedure { t },
        secondProcedureGenerator: { _ in someP }
    )
}
var someP: some Procedure {
    AtomicProcedure { 0 }
}

struct FlatMap
    <First: Procedure,
     Second: Procedure>:
        Procedure {
    
    var firstProcedure: First
    var secondProcedureGenerator: (First.Output)async->Second
    
    func run () async -> Second.Output {
        let firstOutput = await firstProcedure.run()
        let second = await secondProcedureGenerator(firstOutput)
        return await second.run()
    }
}

struct AtomicProcedure <Output>: Procedure {
    var _run: ()async->Output
    func run () async -> Output { await _run() }
}

public protocol Procedure <Output> {
    func run () async -> Output
    associatedtype Output
}

If you put this code into a blank package and run the top function from a unit test you should immediately experience a crash like:

error: memory read failed for 0xb3261800

Any insight into the true source and therefore how to workaround?