Question

myList |> List.filter (fun item ->
    if item.MyValue < 10 then
        sideEffect ()
        true
    else
        false )

If I set a breakpoint at false ), it gets ignored/skipped.

I have to:

        false
)

I’m not so much interested in knowing why this happens (pretty easy to make an educated guess), as in knowing whether this is ever going to be addressed.

Answer 1

It’s not fixed in VS2012, so who knows (too far into the future to predict more). Our debugger support was ‘good enough’ in VS2010 that we chose not to invest much in it this cycle; customers have rarely mentioned the debugger* (perhaps because people find they rarely need to debug F# code?), so we have not prioritized it.

(* – with one exception; people would really like to see intermediate values/return values when e.g. debugging pipelines or large expressions – this request is common to both C# and F# users (though probably more important to F#). In fact, I just looked and it is by far the highest-voted user request for the VS Debugger:

http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/2206747-function-return-value-in-debugger

so go add your voice there.)

It tends to be the case that all these minor debugger issues can be worked around by spreading code out onto more lines or introducing more intermediate variables; it is annoying to change code just to make it more debuggable, but it is worth mentioning the workaround for anyone who really needs it.