Quick Watch shows wrong value on variables with same name

[Dolfik1]

Quick Watch shows wrong value on variables with same name

Repro steps

Provide the steps required to reproduce the problem

1. Paste the following:

let testNullA x =
    let x = // quick watch 1
        if isNull(x) then printf "value is null" // quick watch 2
        else 
            printf "value is not null" // breakpoint 1
    ()

let testNullB x =
    let x = // quick watch 3
        if isNull(x) then null // quick watch 4
        else 
            null // breakpoint 2
    ()

[<EntryPoint>]
let main argv = 
    testNullA "123"
    testNullB "123"
    0

2. Set breakpoints on line with // breakpoint 1 and // breakpoint 2 comments.
3. Start debug
4. Quick watch x on lines with // quick watch n comment

Expected behavior

quick watch 1: x = null
quick watch 2: x = "123"
quick watch 3: x = null
quick watch 4: x = "123"

Actual behavior

quick watch 1: x = "123"
quick watch 2: x = "123"
quick watch 3: x = null
quick watch 4: x = null

Known workarounds

Use different names of variables. For example:

let testNullA x =
    let a = // quick watch 1
        if isNull(x) then printf "value is null" // quick watch 2
        else 
            printf "value is not null" // breakpoint 1
    ()

Related information

Bug reproduced in Visual Studio 2017 with Visual F# Tools Extension 15.4.17051701 and Visual Studio Code with Ionide extension 2.25.13

[dsyme]

I suspect that this is an off-by-one issue in emitting the range information for local variable names in the debug info. I'm not sure though.

So it might be very easy to fix, particularly if some tools are available for dumping the debug information produced

[dsyme]

Fixed