x/tools/internal/lsp: SuggestedFix tests failing on arm64 builders starting between 2022-08-19T17:47:49 and 2022-08-23T21:04:06

[bcmills]

greplogs -l -e FAIL\\s+golang.org/x/tools/internal/lsp --since=2022-08-20 --omit=newcc --details

2022-08-24T16:06:46-587a153-2fc21b5/darwin-arm64-11
2022-08-24T16:06:46-587a153-2fc21b5/darwin-arm64-12
2022-08-24T16:06:46-587a153-2fc21b5/linux-arm64-aws
2022-08-24T16:00:07-587a153-3083529/darwin-arm64-11
2022-08-24T16:00:07-587a153-3083529/darwin-arm64-12
2022-08-24T16:00:07-587a153-3083529/linux-arm64-aws
2022-08-24T15:37:38-587a153-d5aa088/darwin-arm64-11
2022-08-24T15:37:38-587a153-d5aa088/darwin-arm64-12
2022-08-24T15:37:38-587a153-d5aa088/linux-arm64-aws
2022-08-24T14:31:08-587a153-f983a93/darwin-arm64-11
2022-08-24T14:31:08-587a153-f983a93/darwin-arm64-12
2022-08-24T14:31:08-587a153-f983a93/linux-arm64-aws
2022-08-24T12:12:12-587a153-b5a9459/darwin-arm64-11
2022-08-24T12:12:12-587a153-b5a9459/darwin-arm64-12
2022-08-24T12:12:12-587a153-b5a9459/linux-arm64-aws
2022-08-24T08:17:52-587a153-1ab6b79/darwin-arm64-11
2022-08-24T08:17:52-587a153-1ab6b79/darwin-arm64-12
2022-08-24T08:17:52-587a153-1ab6b79/freebsd-amd64-race
2022-08-24T08:17:52-587a153-1ab6b79/linux-arm64-aws
2022-08-24T05:40:28-587a153-1a8dfad/darwin-arm64-11
2022-08-24T05:40:28-587a153-1a8dfad/darwin-arm64-12
2022-08-24T05:40:28-587a153-1a8dfad/linux-arm64-aws
2022-08-24T02:54:32-587a153-75cdd2c/darwin-arm64-11
2022-08-24T02:54:32-587a153-75cdd2c/darwin-arm64-12
2022-08-24T02:54:32-587a153-75cdd2c/linux-arm64-aws
2022-08-24T02:23:58-587a153-7ee220c/darwin-arm64-11
2022-08-24T02:23:58-587a153-7ee220c/darwin-arm64-12
2022-08-24T02:23:58-587a153-7ee220c/linux-arm64-aws
2022-08-23T23:17:55-587a153-1dcef7b/darwin-arm64-11
2022-08-23T23:17:55-587a153-1dcef7b/darwin-arm64-12
2022-08-23T23:17:55-587a153-1dcef7b/linux-arm64-aws
2022-08-23T23:11:53-587a153-aa42997/darwin-arm64-11
2022-08-23T23:11:53-587a153-aa42997/darwin-arm64-12
2022-08-23T23:11:53-587a153-aa42997/linux-arm64-aws
2022-08-23T22:44:18-587a153-ab8a2c5/darwin-arm64-11
2022-08-23T22:44:18-587a153-ab8a2c5/darwin-arm64-12
2022-08-23T22:44:18-587a153-ab8a2c5/linux-arm64-aws
2022-08-23T22:01:05-587a153-0765da5/darwin-arm64-11
2022-08-23T22:01:05-587a153-0765da5/darwin-arm64-12
2022-08-23T22:01:05-587a153-0765da5/linux-arm64-aws
2022-08-23T21:24:14-587a153-60ad3c4/darwin-arm64-11
2022-08-23T21:24:14-587a153-60ad3c4/darwin-arm64-12
2022-08-23T21:24:14-587a153-60ad3c4/linux-arm64-aws
2022-08-23T21:22:15-587a153-a36a0c4/darwin-arm64-11
2022-08-23T21:22:15-587a153-a36a0c4/darwin-arm64-12
2022-08-23T21:04:06-587a153-790d605/darwin-arm64-12

(46 matching logs)

[bcmills]

The first failure in the logs was at CL 421502 (attn @pjweinb), but It's not clear to me whether this is due to a regression in x/tools proper or in the main Go repo. The dashboard appears to be missing test runs for these builders for a run of several CLs due to the high CL churn rate with the tree reopened.

[bcmills]

I'm seeing a lot of these messages in the logs:

 analysis unusedvariable for package golang.org/x/tools/internal/lsp/snippets panicked: invalid start/end token.Pos

CL 424920 would fit that timeframe (CC @mvdan @adonovan), though it's not at all clear to me how that would result in arm64-specific breakage. 🤔

[adonovan]

That change looks completely safe, and it shouldn't even affect timing significantly. I think the scope of the recover is too large---it should include only the analysers, not the setup and postprocessing code, which is where I think this problem is occurring. I'll take a look.