Better anonymous record reporting

[isaacabraham]

Fixes #8091. This provides custom error messages for four cases of mismatched anonymous records:

1. Source is a subset of destination.
2. Source is a superset of destination.
3. Source and destination overlap but both have differences.
4. Source and destination are completely different.

Wording might need to be changed!

[cartermp]

Thanks! This is a great change to the error messages. Just some style nits.

Requesting changes since there are some small test updates that need to be made in the baseline files. You can see which ones here: https://dev.azure.com/dnceng/public/_build/results?buildId=472147&view=ms.vss-test-web.build-test-results-tab&runId=15028460&resultId=100248&paneView=debug

Since this is an error message update there's nothing special here, just copy/pasting the new expected error message into the baseline. It's kind of annoying.

[smoothdeveloper]

just copy/pasting the new expected error message into the baseline. It's kind of annoying.

This can be made less annoying, following the instructions there:

https://github.com/dotnet/fsharp/tree/master/tests/fsharp#workflow-when-adding-or-fixing-tests

[isaacabraham]

@smoothdeveloper I couldn't actually figure out what to do with that script or how to run those BSL tests locally (they weren't even in the solution). How do I do it?

[smoothdeveloper]

@isaacabraham, have you been able to run tests under: https://github.com/dotnet/fsharp/blob/master/tests/fsharp/tests.fs ?

after those ran, the .err files will contain the actual output, you can then adjust the script (it handles the folders explicitly, you need to put the folder names that you are interested in) and run it to copy the .err into .bsl files, review and commit/push.

edit:
me changing a .bsl to make a test fail

running the script (with folder of the test added)

C:\dev\src\github.com\Microsoft\masterfsharp\tests\fsharp\core\byrefs\test.bsl not matching, replacing with C:\dev\src\github.com\Microsoft\masterfsharp\tests\fsharp\core\byrefs\test.err

running the test again:

[cartermp]

Awesome work, thanks!

[abelbraaksma]

Wording might need to be changed!

In the original issue I proposed an alternative text, but it looks like you already made it far better than the original idea. I do have a few suggestions, though, feel free to use them, or not ;)

tcAnonRecdFieldNameMismatch,"This anonymous record has the following missing fields '%s' and the following unexpected extra fields '%s'."

Error messages in F# typically don't use determiners, for consistency, I suggest to simplify it like this (which also removes a redundancy): "Anonymous record misses fields '%s' and has unexpected fields '%s'."

tcAnonRecdFieldNameSubset,"This anonymous record is missing the following fields: '%s'. Please add them."

Same here, I'd suggest: "Anonymous record misses fields '%s'."

tcAnonRecdFieldNameSuperset,"This anonymous record has the following unexpected extra fields '%s'. Please remove them."

And here it would become: "Anonymous record has unexpected fields '%s'."

tcAnonRecdFieldNameDifferent,"This is the wrong anonymous record. The expected record has the following fields: '%s'."

Perhaps something like: "Unexpected anonymous record. The expected anonymous record has fields: '%s'."

[isaacabraham]

@abelbraaksma I'll give it a bash and see how it "looks" locally. A few ideas I had in the past days looked good on paper or in my mind but when I tried them, they didn't print out as well.

We can always iterate on this in the future - I don't believe there's a "no breaking changes" on error messages.

[abelbraaksma]

We can always iterate on this in the future

I agree, even more so for compiler errors.

[abelbraaksma]

Error messages in F# typically don't use determiners, for consistency

While I said that myself, this turns out to be untrue, we do have errors that start with "this expression .... " etc. Right now I'm not so sure if there's any rule-of-thumb w.r.t. grammar/style/wording of errors.

[cartermp]

@isaacabraham is the error message itself how you'd like it?

[isaacabraham]

I'm personally satisfied with it, at least as a means to get feedback from others. It should be consistent enough that tooling could generate fixes on top of it as well.

[cartermp]

I'll merge this. The message is easy to adjust after the fact, so let's get it in!