add code fix for wildcard _ in pattern match for fs43 on |->

[jkone27]

Suggest | _ -> for match mistaken with infix operator |->

add code fix for wildcard operator suggestion in pattern match for fs43, targets:
dotnet/fsharp#15748

as worked in amplifying fsharp session:
https://amplifying-fsharp.github.io/sessions/2023/09/01/

WHY

the operator |-> is not defined, so this is usually just a user forgetting to complete the match

HOW

🤖 Generated by Copilot at df83900

• Add a new code fix for adding a missing wildcard operator to a match expression (link, link)
  • Define a new module FsAutoComplete.CodeFix.AddMissingWildcardOperator in src/FsAutoComplete/CodeFixes/AddMissingWildcardOperator.fs and its signature file in src/FsAutoComplete/CodeFixes/AddMissingWildcardOperator.fsi (link, link)
  • Export a title, a function to try to find the pattern that needs the fix, and a function to apply the fix using the CodeFix type and the SyntaxVisitorBase and SyntaxTraversal utilities (link, link)
• Register the new code fix function in the language server implementations (link, link)
  • Add the function to the list of code fixes supported by the AdaptiveFSharpLspServer type in src/FsAutoComplete/LspServers/AdaptiveFSharpLspServer.fs (link)
  • Add the function to the list of code fixes supported by the FSharpLspServer type in src/FsAutoComplete/LspServers/FsAutoComplete.Lsp.fs (link)
• Add a test case for the new code fix using the test helpers (link, link)
  • Define a new test module FsAutoComplete.Tests.CodeFixTests.AddMissingWildcardOperatorTests in test/FsAutoComplete.Tests.Lsp/CodeFixTests/AddMissingWildcardOperatorTests.fs (link)
  • Check that the code fix can suggest a wildcard pattern for a missing match case in a simple example using the CodeFix and Diagnostics utilities (link)
  • Add the new test module to the list of test modules in the tests function in test/FsAutoComplete.Tests.Lsp/CodeFixTests/Tests.fs (link)

[TheAngryByrd]

@dawedawe mentioned some good fixes

[baronfel]

Needs a format but otherwise LGTM.

[jkone27]

fixed the suggestions, not clear how i run format, can it be added as a git hook at commit phase on master? i am not very familiar with fantomas, would be good if it could be hooked onto dotnet format or .editorconfig i guess most .net devs are familiar with those concepts. formatted the changed files individually with
dotnet fantomas filename.fs

[nojaf]

Hi,

Running this target sets up the git hook:
https://github.com/fsharp/FsAutoComplete/blob/e3353360771969be51ab3c84a57a432cf41816cf/build/Program.fs#L107-L110

dotnet run --project ./build/build.fsproj -- -t EnsureRepoConfig

And I think it would be nice to see a message when
https://github.com/fsharp/FsAutoComplete/blob/e3353360771969be51ab3c84a57a432cf41816cf/Directory.Solution.targets#L10-L12

fails.

Something like Please run "dotnet fantomas src" to format your files.
I'm not sure how to do that one with msbuild trickery.

[edgarfgp]

@jkone27 Could you have a look at the conflicts. Seems that this almost ready :)