x/tools/gopls: add syntax highlighting for go: directives

[findleyr]

Spin off from https://go.dev/issue/50262: we should add semantic token support for go:directives, so that they stand out as semantically significant. That issue was discussing go:embed support, but if we are going to highlight go:embed, we should highlight other go directives as well.

It probably suffices to add logic here:
https://cs.opensource.google/go/x/tools/+/master:gopls/internal/lsp/semantic.go;l=418;drc=fb4bd11ef6feea8f26ff371d1fcca356511e2e26

We already look inside basic lits of importSpecs to highlight package names, I expect this task would be similar:
https://cs.opensource.google/go/x/tools/+/master:gopls/internal/lsp/semantic.go;l=901;drc=fb4bd11ef6feea8f26ff371d1fcca356511e2e26

@vikblom indicated interest in taking this on.

CC @pjweinb

[vikblom]

Thanks for the pointers! I'll give this a look and circle back with questions/patches 👍

[pjweinb]

Emphasizing the go: directives is a good idea. Maybe tokNamespace, which generally seems to be a contrasting color. 1. Some go:directives (e.g. go:build) have to appear before the package statement. Failing to emphasize a go: directive when it is being used incorrectly seems like a good idea too. 2. The comment-handling code is at line 144. vscode does not support overlapping tokens. 3. The new capability would need new tests...

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On Sat, Oct 14, 2023 at 4:32 AM vikblom ***@***.***> wrote: Thanks for the pointers! I'll give this a look and circle back with questions/patches 👍 — Reply to this email directly, view it on GitHub <#63538 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABJIAIZKEIRVRHQMBUJAF3LX7JEYPANCNFSM6AAAAAA57W6SJA> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[vikblom]

Thanks @pjweinb that is very useful input 👍

I checked go:build and there is an existing warning ("misplaced //go:build comment") that pops up even if the directive is a semantic token. The same is true for go:embed warnings implemented in the issue this spun off from.

[gopherbot]

Change https://go.dev/cl/536915 mentions this issue: gopls/internal/lsp: add semantic highlighting for go: directives