Stack underflow when `if` used in `raise`

[kerams]

Repro steps

// run in fsi
open System

let repro (b: bool) = Math.Max (1, raise (Exception (if b then "x" else "y")))

let control (b: bool) = Math.Max (1, String.length (if b then "x" else "y"))

try control true |> ignore; printfn "control: ok" with ex -> printfn "control: %s" (ex.GetType().Name)
try repro true |> ignore; printfn "repro: ok" with ex -> printfn "repro: %s" (ex.GetType().Name)

The original production code looked like

try
    ...
with ...  ->
    return raise (SerializationException (if data.Length > 0 then int data.[0] else 0, "index out of range"))

Expected behavior

control: ok
repro: ok

Actual behavior

control: ok
System.InvalidProgramException: Common Language Runtime detected an invalid program.

ILVerify reports [StackUnderflow] Repro::repro(bool) offset 0x0D

IL_0000: ldc.i4.1
IL_0001: ldc.i4.0
IL_0002: brfalse.s    IL_000c
IL_0004: ldnull
IL_0005: unbox.any    [System.Runtime]System.Int32
IL_000a: br.s         IL_0033
IL_000c: stloc.0      // V_0
IL_000d: stloc.1      // V_1 <- saves a second value, but only one is on the stack -> underflow

Known workarounds

Bind the argument first.

Related information

• Win 11, SDK 11.0.100-rc.1.26425.128