[semantic highlighting] improve fallback scope for macro

[georgewfraser]

• VSCode Version: 1.51.0
• OS Version: MacOS 10.15.7

Steps to Reproduce:

1. Run an extension that uses semantic coloring mark a token as "macro"
2. Observe that no fallback scope is being applied:

Does this issue occur when all extensions are disabled?: Yes/No

Not applicable, this bug can only occur when an extension is using macro syntax coloring.

[georgewfraser]

The fallback scope for "macro" is described in https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide#semantic-token-scope-map

[aeschli]

entity.name.other.preprocessor.macro is defined as the fallback scope, but non of the built-in theme define any color for it.

Is there a better scope to use?

@Colengms Any suggestions?

[Colengms]

@aeschli The TextMate scope for macro used in the original C/C++ semantic colorization feature was: entity.name.function.preprocessor, which we still use as a fallback.

https://code.visualstudio.com/docs/cpp/colorization-cpp

It was mentioned here, when discussing adding scopes to plus themes: #80783

The C/C++ extension currently uses the same semantic token for both function macros and non-function macros.

[georgewfraser]

@aeschli If entity.name.other.preprocessor.macro is the fallback scope, why doesn't it show up in the tooltip? Perhaps that is a separate bug?

[aeschli]

@georgewfraser The tooltip wants to show how the style at the current position was determined. For semantic highlighting it would show the theming rule if it had matched one. As current theme doesn't have theming rules to neither the token type (macro) nor the fallback scope(s), no such information is shown.
Not so much space in the hover, but I'm happy to improve it if we can do it in a space efficient way.

[aeschli]

I pushed a fix to change the macro fallback scope to entity.name.function.preprocessor

[aeschli]

To verify open the https://github.com/microsoft/vscode-extension-samples/tree/master/semantic-tokens-sample, add macro as a supported token. Use the 'Inspect token and scopes' command to verify that it is colored with the color associated with the entity.name.function.preprocessor scope

[github-actions]

This bug has been fixed in to the latest release of VS Code Insiders!

@georgewfraser, you can help us out by confirming things are working as expected in the latest Insiders release. If things look good, please leave a comment with the text /verified to let us know. If not, please ensure you're on version 92192ba of Insiders (today's or later - you can use Help: About in the command palette to check), and leave a comment letting us know what isn't working as expected.

Happy Coding!