Variables that are built-in constants are not highlighted, like `$Error` and `$PSVersionTable`

[o-l-a-v]

Prerequisites

• Write a descriptive title.
• Make sure you are able to repro it on the latest version
• Search the existing issues.

Steps to reproduce

Noticed that both VSCode and GitHub doesn't highlight some variables, like $Error and $PSVersionTable

This:

```powershell
#Requires -Version 5.1
<#
    .SYNOPSIS
        This is just to test code highlighting.
#>

# Input and expected output
[OutputType([System.Void])]
Param()

# Preference variables
$ErrorActionPreference = 'Stop'
$InformationPreference = 'Continue'

# User defined variable
$SomeVariable = [string] 'Text'

# Built-in constants
$Error
$PSHOME
$PSVersionTable

# Values
string without quotes
'string with quotes'
```

Looks like this on GitHub:

#Requires -Version 5.1
<#
    .SYNOPSIS
        This is just to test code highlighting.
#>

# Input and expected output
[OutputType([System.Void])]
Param()

# Preference variables
$ErrorActionPreference = 'Stop'
$InformationPreference = 'Continue'

# User defined variable
$SomeVariable = [string] 'Text'

# Built-in constants
$Error
$PSHOME
$PSVersionTable

# Values
string without quotes
'string with quotes'

And in VSCode:

Expected behavior

Highlight.js demo https://highlightjs.org/demo does as I expect it to:

PowerShell ISE and the PowerShell terminal too:

Actual behavior

Steps to reproduce

Error details

No response

Environment data

PowerShell 7.4.1 x64 on Windows 11 23H2
VSCode 1.87.2, vscode-powershell v2024.0.0 and v2024.3.1-preview

Version

Latest?

Visuals

No response

[o-l-a-v]

Is the problem that the defined textmate scope does not have a theme selector?

In https://github.com/microsoft/vscode/blob/main/extensions/powershell/syntaxes/powershell.tmLanguage.json I see:

{
  "captures": {
    "0": { "name": "support.constant.variable.powershell" },
    "1": { "name": "punctuation.definition.variable.powershell" },
    "3": { "name": "variable.other.member.powershell" }
  },
  "comment": "These are the other built-in constants.",
  "match": "(\\$)(?i:(Error|ExecutionContext|Host|Home|PID|PsHome|PsVersionTable|ShellID))\\b"
}

Which results in textmate scopes support.constant.variable.powershell source.powershell, which says foreground No theme selector.

So maybe it just uses wrong textmate scope?

[o-l-a-v]

Dracula theme have worked around this like so https://github.com/dracula/visual-studio-code/blob/main/src/dracula.yml:

  - name: Powershell constants mistakenly scoped to `support`, rather than `constant` (edge)
    scope:
    - support.constant
    settings:
      fontStyle: normal
      foreground: *PURPLE

---

VSCode built in themes does not have it, like "Dark Modern":

• Parent it inherits tokenColors from: https://github.com/microsoft/vscode/blob/main/extensions/theme-defaults/themes/dark_vs.json
• The overrides for "Dark Modern": https://github.com/microsoft/vscode/blob/main/extensions/theme-defaults/themes/dark_modern.json

---

I think the fix should be to use a TextMate scope that is more common in VSCode themes.

This was suggested to me by Gemini Fast and worked in my testing with VSCode + Dark Modern theme:

• From support.constant.variable.powershell.
• To variable.other.readwrite.constant.powershell.

---

C# uses variable.other.readwrite.cs:

• https://github.com/microsoft/vscode/blob/main/extensions/csharp/syntaxes/csharp.tmLanguage.json