Better compile error output when using arguments instead of types

[jean-lourenco]

Following @estebank sugestion on issue #18945 (comment)

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @nikomatsakis (or someone else) soon.

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[petrochenkov]

This will probably look better as a second help: on a separate line.

[nikomatsakis]

I think I also would prefer a second help

[jean-lourenco]

The recommended changes were implemented.

EDIT: Nevermind, I broke some tests 😅

[estebank]

@jean-lourenco the broken test is to be expected and correct, if you could fix it and squash all your commits into one we can approve.

[nikomatsakis]

Looks like you have to update parse-fail/require-parens-for-chained-comparison.rs to something like this:

    f<X>();
    //~^ ERROR: chained comparison operators require parentheses
    //~| HELP: use `::<...>` instead of `<...>`
    //~| HELP: or use `(...)`

[jean-lourenco]

Now the tests are green 🎉
Thank you guys for your help!

[nikomatsakis]

@bors r+

[bors]

📌 Commit db91b00 has been approved by nikomatsakis

[nikomatsakis]

Thanks @jean-lourenco