Mishandling of some complex collections

[psfinaki]

Issue created from fantomas-online

Code

namespace Repro

module SomeModule =

    let Repro () =
        let stuff =
            [
                ("s1",
                 Some "
s2");
                ("s3", 
                 Some "s4");
            ]

        0

Result

namespace Repro

module SomeModule =

    let Repro () =
        let stuff =
            [ ("s1",
               Some
                   "
s2") (
                  "s3",
                  Some "s4"
              ) ]

        0

Problem description

Please describe here the Fantomas problem you encountered.
Check out our Contribution Guidelines.

Extra information

• The formatted result breaks my code.
• The formatted result gives compiler warnings.
• I or my company would be willing to help fix this. - somewhat, maybe :)

Discovered this when applying Fantomas to some code in F# compiler: dotnet/fsharp#14782
In particular, see QuickInfoProviderTests.

This repro is a very minified version of the code above.

Options

Fantomas v5.2 branch at 1/1/1990

Default Fantomas configuration

_{Did you know that you can ignore files when formatting from fantomas-tool or the FAKE targets by using a .fantomasignore file?}

[josh-degraw]

I'm surprised that even compiles with multiline strings without using """! Is that a documented accepted behavior? FWIW it looks like it still breaks even with the """ though unfortunately

[psfinaki]

Yeah you can go as simple as this:

Looks like this is documented, you can even add slashes to further manipulate the output.

Not that this is beautiful code... But we just have some old ugly tests where a lot of code is formatted somewhat weirdly and I was just onboarding that on Fantomas. And yeah I tried to dumbly add more quotes but that didn't work :D

[nojaf]

Hello, thank you for reporting this issue.
This is a tricky one, after the first format, I would expect the parser tries to see both paren expressions as an application.

Can you not drop the parentheses? (sample)

[psfinaki]

Can you not drop the parentheses?

Seems to work in the original code. Cool. But well, that's what Fantomas could do for me :P

[psfinaki]

Oh and by the way. I don't want to overbugreport you but Fantomas Online actually shows something else than what happens in the real life:

Neither works but just FYI.

[nojaf]

Cool. But well, that's what Fantomas could do for me :P

You can't make that judgement call in every possible situation using only untyped tree information.
Because of that reason, we have decided against having such functionality in Fantomas.
This is more something for an IDE to clean up. Mine at least has that 😏.

Fantomas Online actually shows something else than what happens in the real life:

You most likely didn't enter your settings in the online tool or used a different version.

[psfinaki]

You most likely didn't enter your settings in the online tool or used a different version.

For completeness, here is my local repro - before I learned about Fantomas online :D
FantomasRepro.zip

I was running dotnet tool run fantomas . -r.

But anyway, this is by far not a blocker now - thanks for the quick response here :)