Go Implementation Lens

A VS Code extension that enhances Go development by providing instant visibility into interface-implementation relationships. Navigate seamlessly between interfaces and their implementations with visual indicators and smart navigation - bringing GoLand/IntelliJ-style functionality to VS Code.

Key Features

🔍 Interface Implementation Discovery

• Instant Visibility: See how many implementations an interface has directly in your code
• Bidirectional Navigation: Jump from interface → implementations or implementation → interfaces
• Visual Indicators: Gutter icons provide at-a-glance awareness of relationships

🎯 Smart Navigation

• Direct Jump: Single implementation? Go straight to it with one click
• Organized Sidebar: Multiple references/implementations? Browse through a hierarchical view
• Quick Pick Fallback: Prefer VS Code's built-in picker? Toggle with one setting

📊 Organized Sidebar View ⭐ New Feature

Experience a revolutionary way to browse references and implementations with our hierarchical sidebar that organizes results by package, file, and function for maximum clarity.

Key Benefits:

• Package Grouping: See which packages contain references at a glance
• File Organization: Browse by individual files within each package
• Function Context: Understand exactly where references occur within functions
• Expandable Tree: Drill down from high-level overview to specific code lines
• Always Available: Stays open while you navigate, unlike popup dialogs

⚡ Performance Optimized

• Intelligent Caching: Document-level cache minimizes gopls calls
• Real-time Updates: Changes reflect immediately without manual refresh
• Lightweight: No performance impact on large codebases

🎨 Customizable Display

• CodeLens: "N implementations" above interfaces, "Implements: X, Y" above types
• Gutter Icons: Visual markers for quick identification
• Sidebar Navigation: Organized tree view showing references and implementations grouped by package and file
• Flexible Configuration: Enable/disable features to match your workflow

How It Works

The extension leverages gopls (Go language server) through VS Code's executeImplementationProvider API, ensuring accurate and up-to-date results. This approach provides:

• Accuracy: Uses the same implementation detection as Go's compiler
• Reliability: No custom parsing means fewer edge cases
• Compatibility: Works seamlessly with all Go project structures

Usage

1. Open any Go file - The extension activates automatically
2. Look for indicators:
   • 📍 Above interfaces: "N implementations" link
   • 📍 Above structs: "Implements: Interface1, Interface2..." link
   • 📍 Gutter icons marking interfaces and implementations
3. Click to navigate:
   • Single target: Direct navigation to the location
   • Multiple targets: Organized sidebar view with package/file/function hierarchy
   • Alternative: Quick pick popup (configurable via settings)

Requirements

• VS Code 1.74.0 or higher
• Go extension for VS Code (with gopls enabled)

Configuration

Configuration Examples

Minimal Setup (implementations only, no references or gutter icons):

{
  "goImplementationLens.showReferences": false,
  "goImplementationLens.showGutterIcons": false,
  "goImplementationLens.useSidebar": false
}

Implementations Only (no reference tracking):

{
  "goImplementationLens.showReferences": false
}

Maximum Visibility:

{
  "goImplementationLens.showOnInterfaceHeader": true,
  "goImplementationLens.showGutterIcons": true,
  "goImplementationLens.showReferences": true,
  "goImplementationLens.useSidebar": true
}

🔄 Navigation Modes

🌟 Sidebar Mode (Default - useSidebar: true) Opens an organized tree view that stays visible while you browse:

References to MyInterface
└── 📦 controllers (3 references)
    └── 📄 user_controller.go (3 references)
        └── ⚙️ func CreateUser
            ├── myInterface.DoSomething()
            ├── result := myInterface.Process()
            └── return myInterface.Validate()

⚡ Quick Pick Mode (useSidebar: false) Shows a searchable file picker similar to "Go to File":

Go to Implementation (3 found)
├── 📄 service.go          internal/services
│   Line 45: func (s *Service) GetData()...
├── 📄 temp_service.go     internal/services  
│   Line 23: func (t *TempService) GetData()...
└── 📄 grpcHandler.go      internal/controllers
    Line 67: func (h *Handler) GetData()...

Which to choose?

• Sidebar: Best for exploring complex codebases with many references
• Quick Pick: Best for quick navigation when you know what you're looking for

Development

# Install dependencies
npm install

# Compile
npm run compile

# Watch mode
npm run watch

Testing

Press F5 in VS Code to launch a new Extension Development Host window with the extension loaded.