Simplify copilot-instructions.md

.github/copilot-instructions.md

@@ -8,25 +8,17 @@ This repository implements:
 
 - **Razor Compiler**: The core Razor compilation engine and source generators
 - **Language Server**: LSP-based language services for cross-platform editor support
-- **Visual Studio Integration**: Rich editing experience and tooling for Visual Studio 
+- **Visual Studio Integration**: Rich editing experience and tooling for Visual Studio
+- **Visual Studio Code Extension**: Rich editing experience and tooling for Visual Studio
 - **IDE Tools**: Debugging, IntelliSense, formatting, and other developer productivity features
 
-### Key Components
-
-| Component | Purpose | Key Projects |
-|-----------|---------|--------------|
-| **Compiler** | Core Razor compilation and code generation | `Microsoft.AspNetCore.Razor.Language`, `Microsoft.CodeAnalysis.Razor.Compiler` |
-| **Language Server** | Cross-platform language services via LSP | `Microsoft.AspNetCore.Razor.LanguageServer` |
-| **Visual Studio** | VS-specific tooling and integration | `Microsoft.VisualStudio.RazorExtension`, `Microsoft.VisualStudio.LanguageServices.Razor` |
-| **Workspaces** | Project system and document management | `Microsoft.CodeAnalysis.Razor.Workspaces` |
-
 ## Razor Language Concepts
 
 When working with this codebase, understand these core Razor concepts:
 
 ### File Types and Extensions
 - `.razor` - Blazor components (client-side and server-side)
-- `.cshtml` - Razor views and pages (ASP.NET Core MVC/Pages)
+- `.cshtml` - Razor views and pages (ASP.NET Core MVC/Pages) also referred to as "Legacy" in the codebase
 
 ### Language Kinds
 Razor documents contain multiple languages:
@@ -35,51 +27,24 @@ Razor documents contain multiple languages:
 - **HTML markup** - Static HTML and dynamic content
 - **JavaScript/CSS** - Client-side code within Razor files
 
-### Key Architecture Patterns
-- **RazorCodeDocument** - Central document model containing parsed syntax tree and generated outputs
-- **Language Server Protocol (LSP)** - Cross-platform editor integration
-- **Virtual Documents** - Separate C# and HTML projections for tooling
-- **Document Mapping** - Translation between Razor and generated C# positions
-
 ## Development Guidelines
 
-### Code Style and Patterns
-
-Follow these patterns when contributing:
-
-```csharp
-// ✅ Prefer readonly fields and properties
-private readonly ILogger _logger;
-
-// ✅ Use explicit interface implementations for internal contracts
-internal sealed class MyService : IMyService
-{
-    public void DoWork() { }
-}
-
-// ✅ Use cancellation tokens in async methods
-public async Task<Result> ProcessAsync(CancellationToken cancellationToken)
-{
-    // Implementation
-}
-
-// ✅ Follow null-checking patterns
-public void Method(string? value)
-{
-    if (value is null)
-    {
-        return;
-    }
-
-    // Use value here
-}
-```
+### Coding Patterns
+
+- Always build and test with `build.sh -test` before submitting PRs, without specifying a project or test filter
+- Write clear, concise, and maintainable code
+- Always place `[WorkItem]` attributes on tests for tracking
+- Prefer immutable collection types and pooled collections where possible
+- Use `using` statements for disposable resources
+- Ensure proper async/await patterns, avoid `Task.Wait()`
 
 ### Testing Patterns
 
+- Add appropriate test coverage for new features
 - Prefer `TestCode` over plain strings for before/after test scenarios
 - Prefer raw string literals over verbatim strings
 - Ideally we test the end user scenario, not implementation details
+- Consider cross-platform compatibility by testing path handling and case sensitivity where applicable
 
 ### Architecture Considerations
 
@@ -92,55 +57,14 @@ public void Method(string? value)
 
 ### Prerequisites
 - .NET 8.0+ SDK (latest version specified in `global.json`)
-- Visual Studio 2022 17.8+ or VS Code with C# extension
+- Visual Studio 2026 (Windows) or VS Code with C# extension (Windows, macOS or Linux)
 - PowerShell (for Windows build scripts)
 
 ### Building
 - `./restore.sh` - Restore dependencies
 - `./build.sh` - Full build
-- `./build.sh -test` - Build and run tests
-
-### Visual Studio Development
-- `./startvs.ps1` - Open Visual Studio with correct environment
-- `./build.cmd -deploy` - Build and deploy VS extension for testing
-
-## Project Structure Navigation
-
-```
-src/
-├── Compiler/           # Core Razor compilation engine
-│   ├── Microsoft.AspNetCore.Razor.Language/     # Core language APIs
-│   └── Microsoft.CodeAnalysis.Razor.Compiler/   # Roslyn integration
-├── Razor/             # Language server and tooling
-│   ├── src/Microsoft.AspNetCore.Razor.LanguageServer/  # LSP implementation
-│   ├── src/Microsoft.VisualStudio.RazorExtension/      # VS package
-│   └── test/          # Language server tests
-└── Shared/            # Common utilities and test helpers
-```
+- DO NOT USE `dotnet build` directly
 
-## Debugging and Diagnostics
-
-### Language Server Debugging
-- Use F5 debugging in VS with `Microsoft.VisualStudio.RazorExtension` as startup project
-- Check language server logs in VS Output window (Razor Logger Output)
-
-### Common Issues
-- **Performance**: Check document mapping efficiency and async/await usage
-- **Cross-platform**: Test path handling and case sensitivity
-- **Memory**: Use `using` statements for disposable resources
-- **Threading**: Ensure proper async/await patterns, avoid `Task.Wait()`
-
-## Contributing
-
-- Follow the [Contributing Guidelines](CONTRIBUTING.md)
-- Build and test locally before submitting PRs
-- Add appropriate test coverage for new features
-- Update documentation for public API changes
-- Consider cross-platform compatibility in all changes
-
-## Useful Resources
-
-- [ASP.NET Core Razor documentation](https://docs.microsoft.com/aspnet/core/razor-pages)
-- [Blazor documentation](https://learn.microsoft.com/en-gb/aspnet/core/blazor/?)
-- [Language Server Protocol specification](https://microsoft.github.io/language-server-protocol/)
-- [Build from source instructions](docs/contributing/BuildFromSource.md)
+### Testing
+- `./build.sh -test` - Build and run tests
+- DO NOT USE `dotnet test` directly