issue_130_7 implementing new features

[rajcspsg]

@mark-i-m I have created new section implementing new features based on the forge document.

Also, I'm not sure about the how to add a test covering your feature gate, change for simple syntactic things and doing more advanced gates by looking at sess.features.your_feature_here as a boolean for the issue #98.

[mark-i-m]

Thanks @rajcspsg! I'll take a look soon.

[mark-i-m]

Thanks @rajcspsg 👍

I think we should remove the parts that are aimed more at team members than general contributors. I've tried to leave a comment at the parts I think we can remove/change.

Also, you will need to hard-wrap all the lines to respect the 100 char limit.

[mark-i-m]

I believe it is now "all but two"? cc @Mark-Simulacrum

[shepmaster]

Did you want to rename the file to be plural as well?

[mark-i-m]

Also, please don't forget all the comments that Github "helpfully" collapsed (there are 8).

[rajcspsg]

@mark-i-m @shepmaster I updated the book for the changes requested. Please review and let me know your comments.

[mark-i-m]

@shepmaster Do you know how many people are required to check off on pFCP to get to FCP?

[mark-i-m]

LGTM :)

I left a few minor nits, but other than that r=me.

I would still like to hear back from somebody who knows what it takes to start FCP. (@shepmaster?)

[mark-i-m]

Thanks!

[rajcspsg]

@mark-i-m I remember you asked few more things on this in this comment. But I'm not sure where to find the same.

[mark-i-m]

@rajcspsg Thanks for reminding me. Going through the list in #98:

how to add a feature gate in the code

I think this is reasonably covered in what you already wrote.

how to add a test covering your feature gate

Generally, these are normal ui tests that follow this pattern:

• Write a program that uses a feature but does not use the feature gate.
• Ensure that we get an error.

For example, consider this test that checks that asm (inline assembly) is feature gated: https://github.com/rust-lang/rust/blob/master/src/test/ui/feature-gates/feature-gate-asm.rs. The corresponding stderr file is: https://github.com/rust-lang/rust/blob/master/src/test/ui/feature-gates/feature-gate-asm.stderr

The point is just to make sure that the feature is not usable without the feature gate. When the feature is stabilized, the test can be deleted.

how to change for simple syntactic things

Hmmm... I'm not sure what Niko meant by this.

how to do more advanced gates by looking at sess.features.your_feature_here as a boolean

This seems to already be covered in what you wrote.

[rajcspsg]

Thanks @mark-i-m We are good with everything expect how to change for simple syntactic things right?

[mark-i-m]

@rajcspsg I'm not really sure what Niko meant by that. I think what we have is good enough for now, but I left a comment on the other thread asking for Niko's input.

If you want to open a PR about feature gate tests, that would be appreciated.