（前向）管道运算符可以/是否可以阻止尾部调用优化？

根据提供的最小情况，如果代码以64位版本在释放模式下运行，它将失败并产生堆栈溢出。如果代码以32位模式在发布模式下运行，则它将成功。

注意：下图显示了在32位和64位之间进行选择的选项Prefer 32-bit。

增加堆栈大小将导致代码在64位释放模式下成功。这是通过使用Thread构造函数完成的。

[<EntryPoint>]
let main _ =

    let test () =
        let r = KissRandom()
        let n = r.Normal()
        Seq.item 20000 n |> printfn "%f"

    /// The greatest maximum-stack-size that should be used
    /// with the 'runWithStackFrame' function.
    let STACK_LIMIT = 16777216

    /// Run a function with a custom maximum stack size.
    /// This is necessary for some functions to execute
    /// without raising a StackOverflowException.
    let runWithCustomStackSize maxStackSize fn =
        // Preconditions
        if maxStackSize < 1048576 then
            invalidArg "stackSize" "Functions should not be executed with a \
                maximum stack size of less than 1048576 bytes (1MB)."
        elif maxStackSize > STACK_LIMIT then
            invalidArg "stackSize" "The maximum size of the stack frame should \
                not exceed 16777216 bytes (16MB)."

        /// Holds the return value of the function.
        let result = ref Unchecked.defaultof<'T>

        // Create a thread with the specified maximum stack size,
        // then immediately execute the function on it.
        let thread = System.Threading.Thread ((fun () -> result := fn()), maxStackSize)
        thread.Start ()

        // Wait for the function/thread to finish and return the result.
        thread.Join ()
        !result

    /// Runs a function within a thread which has an enlarged maximum-stack-size.
    let inline runWithEnlargedStack fn =
        runWithCustomStackSize STACK_LIMIT fn


//    test ()       // Fails with stack overflow in 64-bit mode, Release
                    // Runs successfully in 32-bit mode, Release

    runWithEnlargedStack test
    
    printf "Press any key to exit: "
    System.Console.ReadKey() |> ignore
    printfn ""

    0

这段代码来自FSharp-logic-examples，尤其是Anh-Dung Phan

虽然我没有检查根本原因，但我怀疑这是因为64位项目的大小大于32位项目的大小，即使放入堆栈和两种版本的堆栈大小均保持不变，项目大小的增加使堆栈所需的内存超过1 MB的限制。

TL; DR

这是一个有趣且启发性的问题。我很高兴被问到。

最初，该问题似乎与使用|>和TCO有关，由于仍然很有价值，我将其留给了答案。我还要感谢OP的响应和帮助，很高兴能帮助与您合作而不是反对您的人。

在以下递归代码中，并|>在Visual Studio中以“调试”模式运行时，将导致StackOverflow。

如果从bin\release目录中的命令行启动它，则不会导致StackOverflow。

使用Visual Studio 15社区

[<EntryPoint>]
let main argv = 

    let largeList = 
        printfn "Creating large list"
        [
            for i in 1 .. 100000000 do
                yield i
        ]

    // causes StackOverflow in Debug
    // No StackOverflow in Release
    let sum4 l =
        printfn "testing sum4"
        let rec sumInner4 l acc =
            match l with
            | h::t -> 
                let acc = acc + h
                acc |> sumInner4 t
            | [] -> acc
        sumInner4 l 0

    let result4 = sum4 largeList
    printfn "result4: %A" result4

在Visual Studio工具栏中设置发布或调试的位置

调试模式下的项目选项为

在“发布”模式下项目的选项是

tldr;

In the process of testing this I created 16 different test and built them in both debug and release mode and verified if they ran to completion or threw a stack overflow. The 16 are broken down into a set of 4 with 4 cases each. The cases 1,5,9,13 are a negative and produce a stack overflow to ensure that a stack overflow can be created. Cases 2,6,10,14 are a positive to show that the tail call is working and not causing a stack overflow. Cases 3,7,11,15 show a tail call with an operation done in the same statement as the tail call, and to be one factorization away from the test cases using |>; these work as expected. Cases 4,8,12,16 use |> and shows when it does and does not work in debug mode, which is probably a surprise to many. Cases 1-4 and 9-12 use a function of the form f x y, cases 8-11 use a function of the form f x and cases 12-16 use a function of the form f x y z. I originally did the first 8 test cases but after Keith's comment did 4 more which don't use a list but still use a function of the from f x y and present the unexpected result and then did 4 more that use a function of the form f x y z.

To run a test you will have to comment out all but the one test you plan to run and the build it once in debug mode, which can then be run from within Visual Studio, and then again build it in release mode and run it. I run it from a command line to ensure I am running the release version.

[<EntryPoint>]
let main argv = 

    let largeList = 
        printfn "Creating large list"
        [
            for i in 1 .. 100000000 do
                yield i
        ]

    // causes StackOverflow in Debug
    // causes StackOverflow in Release
    //   Negative confirmation
    //   A supposed tail call that DOES cause a stack overflow in both debug and release mode
    //   options: f x y
    let sum1 l = 
        printfn "test 01: "
        let rec sum1Inner l acc =
            match l with
            | h::t -> 
                let acc = acc + h
                1 + sum1Inner t acc
            | [] -> acc
        sum1Inner l 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   Positive confirmation
    //   A tail call that DOES NOT cause a stack overflow in both debug and release mode
    //   options: f x y
    let sum2 l =
        printfn "test 02: "
        let rec sum2Inner l acc =
            match l with
            | h::t -> 
                let acc = acc + h
                sum2Inner t acc
            | [] -> acc
        sum2Inner l 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case
    //   options: f x y and no |>
    let sum3 l =
        printfn "test 03: "
        let rec sum3Inner l acc =
            match l with
            | h::t -> 
                sum3Inner t (acc + h)
            | [] -> acc
        sum3Inner l 0
        
    // causes StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case
    //   options: f x y and |>
    let sum4 l =
        printfn "test 04: "
        let rec sum4Inner l acc =
            match l with
            | h::t -> 
                let acc = acc + h
                acc |> sum4Inner t
            | [] -> acc
        sum4Inner l 0
        
    // causes StackOverflow in Debug
    // causes StackOverflow in Release
    //   Negative confirmation
    //   A supposed tail call that DOES cause a stack overflow in both debug and release mode
    //   options: f x
    let sum5 () =
        printfn "test 05: "
        let rec sum5Inner x =
            match x with 
            | 10000000 -> x
            | _ -> 
                let acc = x + 1
                1 + sum5Inner acc
        sum5Inner 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   Positive confirmation
    //   A tail call that DOES NOT cause a stack overflow in both debug and release mode
    //   options: f x
    let sum6 () =
        printfn "test 06: "
        let rec sum6Inner x =
            match x with 
            | 10000000 -> x
            | _ -> 
                let acc = x + 1
                sum6Inner acc
        sum6Inner 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //  A test case
    //  options: f x and no |>
    let sum7 l =
        printfn "test 07: "
        let rec sum7Inner x =
            match x with 
            | 10000000 -> x
            | _ -> sum7Inner (x + 1)
        sum7Inner 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case
    //   options: f x and |>
    let sum8 () =
        printfn "test 07: "
        let rec sumInner8 x =
            match x with
            | 10000000 -> x
            | _ -> 
                let acc = x + 1
                acc |> sumInner8 
        sumInner8 0

    // causes StackOverflow in Debug
    // causes StackOverflow in Release
    //   Negative confirmation"
    //   A supposed tail call that DOES cause a stack overflow in both debug and release mode"
    //   options: f x y"
    let sum9 () = 
        printfn "test 09: "
        let rec sum9Inner x y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                1 + sum9Inner x acc
        sum9Inner 1 0   
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   Positive confirmation
    //   A tail call that DOES NOT cause a stack overflow in both debug and release mode
    //   options: f x y
    let sum10 () =
        printfn "test 10: "
        let rec sum10Inner x y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                sum10Inner x acc
        sum10Inner 1 0

    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case
    //   options: f x y and no |>
    let sum11 () =
        printfn "test 11: "
        let rec sum11Inner x y =
            match y with
            | 10000000 -> y
            | _ -> 
                sum11Inner x (x + y) 
        sum11Inner 1 0
        
    // causes StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case
    //   options: f x y and |>
    let sum12 () =
        printfn "test 12: "
        let rec sum12Inner x y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                acc |> sum12Inner x
        sum12Inner 1 0

    // causes StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case"
    //   options: f x y and |>"
    let sum12 () =
        printfn "test 12: "
        let rec sum12Inner x y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                acc |> sum12Inner x
        sum12Inner 1 0

    // causes StackOverflow in Debug
    // causes StackOverflow in Release
    //   Negative confirmation"
    //   A supposed tail call that DOES cause a stack overflow in both debug and release mode"
    //   options: f x y"
    let sum13 () = 
        printfn "test 13: "
        let rec sum13Inner x z y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                1 + sum13Inner x z acc 
        sum13Inner 1 "z" 0
        
    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   Positive confirmation"
    //   A tail call that DOES NOT cause a stack overflow in both debug and release mode"
    //   options: f x y"
    let sum14 () =
        printfn "test 14: "
        let rec sum14Inner x z y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                sum14Inner x z acc
        sum14Inner 1 "z" 0

    // No StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case"
    //   options: f x y and no |>"
    let sum15 () =
        printfn "test 15: "
        let rec sum15Inner x z y =
            match y with
            | 10000000 -> y
            | _ -> 
                sum15Inner x z (x + y) 
        sum15Inner 1 "z" 0

    // causes StackOverflow in Debug
    // No StackOverflow in Release
    //   A test case"
    //   options: f x y and |>"
    let sum16 () =
        printfn "test 16: "
        let rec sum16Inner x z y =
            match y with
            | 10000000 -> y
            | _ -> 
                let acc = x + y
                acc |> sum16Inner x z
        sum16Inner 1 "z" 0

    let result1 = sum1 largeList
    printfn "result1: %A" result1

    let result2 = sum2 largeList
    printfn "result2: %A" result2

    let result3 = sum3 largeList
    printfn "result3: %A" result3

    let result4 = sum4 largeList
    printfn "result4: %A" result4

    let result5 = sum5 ()
    printfn "result5: %A" result5

    let result6 = sum6 ()
    printfn "result6: %A" result6

    let result7 = sum7 ()
    printfn "result7: %A" result7

    let result8 = sum8 ()
    printfn "result8: %A" result8

    let result9 = sum9 ()
    printfn "result9: %A" result9

    let result10 = sum10 ()
    printfn "result10: %A" result10

    let result11 = sum11 ()
    printfn "result11: %A" result11

    let result12 = sum12 ()
    printfn "result12: %A" result12

    let result13 = sum13 ()
    printfn "result13: %A" result13

    let result14 = sum14 ()
    printfn "result14: %A" result14

    let result15 = sum15 ()
    printfn "result15: %A" result15

    let result16 = sum16 ()
    printfn "result16: %A" result16
    
    printf "Press any key to exit: "
    System.Console.ReadKey() |> ignore
    printfn ""

    0 // return an integer exit code

Additional, new info

EDIT: This thread on Github has Don Syme, creator of F#, specifically mention that:

[...]其次，您是正确的，即使是尾叫，我们也不保证优化对f <| x或使用x |> f任何类似的功能f x。