# Objective
Closes#60928
Currently, only the declaration of parameters in a function header is
highlighted as `variable.parameter`. Inside the function body,
parameters are highlighted as normal variables, making them
indistinguishable from local variables.
This PR ensures consistent highlighting for parameters throughout their
entire scope, helping developers distinguish between function inputs and
locally defined variables.
## Solution
- Updated the `default_semantic_token_rules.json`: when the token type
is `parameter`, no matter what token modifiers are, it is now mapped to
`variable.parameter` highlight style.
## Testing
Tested locally with Rust. The improvement in visual hierarchy is
demonstrated in the comparison below.
## Self-Review Checklist:
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards
([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
and
[icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md)
guidelines)
- [ ] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
## Showcase
| Before | After |
| :---: | :---: |
| <img width="1178" height="400" alt="before"
src="https://github.com/user-attachments/assets/90a01543-2dcc-41e0-a2a3-f8020c6d77ee"
/> | <img width="1194" height="387" alt="after"
src="https://github.com/user-attachments/assets/c81ba273-2ea7-4d38-b7df-a6069c09c28a"
/>|
---
Release Notes:
- Improved semantic token highlighting to distinguish function
parameters from local variables.
## Context
Zed's semantic token highlighting does not cover all token types
returned by language servers, so the highlighting looks fairly primitive
compared with tree-sitter highlighting, especially for Python language
servers. This PR adds some global and Python-specific rules for better
highlighting.
I need to admit that the built-in Python language servers currently have
weak semantic highlighting implementations. Pylance, the closed-source
Python language server from Microsoft, provides the best highlighting
for now, but I think ty will do better, even though it still has a long
way to go.
## How to Review
Basically, this is a rule-adding change. Some rules are made global, and
some are made Python-specific.
## Self-Review Checklist
<!-- Check before requesting review: -->
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
Release Notes:
- Improved semantic token highlighting for parameters and Python
Part of #7450
Big thanks to @macmv for pushing this forwards so much!
Rebased version of https://github.com/zed-industries/zed/pull/39539 as
working on an in-org branch simplifies a lot of things for us)
Release Notes:
- Added LSP semantic tokens highlighting support
---------
Co-authored-by: Neil Macneale V <neil.macneale.v@gmail.com>
Co-authored-by: Kirill Bulatov <kirill@zed.dev>
Co-authored-by: Zed Zippy <234243425+zed-zippy[bot]@users.noreply.github.com>
