doc/go1.16: document vet changes for Go 1.16

[dmitshur]

As of filing this issue, the Go 1.16 draft release notes contained the following HTML:

<h3 id="vet">Vet</h3>

<p>
  TODO

  <!-- CL 235677: https://golang.org/cl/235677: cmd/vet: bring in pass to catch invalid uses of testing.T in goroutines -->
</p>

Per golang.org/s/release, it's a release blocker for Go 1.16 Beta 1 to have a complete draft of the eventual release notes, and so the TODO needs to be resolved.

A sequence of steps to resolve this issue may be:

1. Come up with a draft release note entry in this issue, then move the issue to NeedsFix state.
2. Send a CL with "doc/go1.16:" prefix and include "For doc: write Go 1.16 release notes #40700. Fixes #{this issue}." in the body.

[dmitshur]

@timothy-king has offered to take this. Thanks!

[gopherbot]

Change https://golang.org/cl/274617 mentions this issue: doc/go1.16: add vet release note for CL 235677

[randall77]

We might also want to mention https://go-review.googlesource.com/c/tools/+/248686 (vet pass to check for invalid frame pointer usage).

[randall77]

Actually, that change has not been vendored in from x/tools yet. Is that scheduled to happen at some point, or should I do that explicitly?

[dmitshur]

@randall77 I'm looking to pull in changes that are in scope for Go 1.16 in CL 275446 (which may end up being split into smaller commits, or otherwise changed not to pull everything in). That is to say, it should happen, but it's not guaranteed to. If it's important for it to be included in Go 1.16 beta 1, please file a separate issue for it and CC me on it. You can send a CL that updates just x/tools to resolve it.

Edit: I see that it'll need a change in cmd/vet to start using the new framepointer package, not just a newer x/tools version, so a separate issue is definitely needed.

[randall77]

Ok, I'll open a new issue and prepare some CLs.

[timothy-king]

@dmitshur Can you cc me if framepointer is added to the release?

[dmitshur]

@timothy-king Please see CL 276372 and CL 276373 that @randall77 just sent.