TypeGuessr

Warning: This project is under active development. Breaking changes may occur without notice.

CHANGELOG will be maintained once the project reaches a stable phase. Until then, please refer to the commit history.

A Ruby LSP addon that provides heuristic type inference to enhance IDE features like Hover and Go to Definition.

Features

• Type Inference: Automatically infers variable types based on method call patterns
• Hover Tooltips: Shows guessed types when hovering over variables
• Heuristic Approach: Works without type annotations by analyzing method usage
• Smart Matching: Finds classes that have all the methods called on a variable

Installation

TypeGuessr is a Ruby LSP addon. Add it to your project's Gemfile under the development group:

group :development do
  gem 'type-guessr', require: false
end

Then run:

bundle install

After installation, restart your editor or reload the Ruby LSP server to activate the addon.

Usage

Once installed, the addon will automatically be loaded by Ruby LSP. Hover over variables, parameters, or instance variables to see guessed types.

Example

class Recipe
  def ingredients
    []
  end

  def steps
    []
  end
end

def process(recipe)
  recipe.ingredients  # Hover over 'recipe' shows: Guessed type: Recipe
  recipe.steps
end

The addon analyzes method calls (ingredients, steps) and finds that only the Recipe class has both methods, so it infers the type as Recipe.

Configuration

Create a .type-guessr.yml file in your project root to customize behavior. See .type-guessr.yml.example for all available options.

After changing configuration, restart Ruby LSP (VSCode: reload window).

Debug Mode

When debug: true, the addon will:

• Log debug information to stderr
• Show inference basis in hover tooltips
• Start a debug web server (unless debug_server: false)

Debug Web Server

When enabled, a web server starts at http://127.0.0.1:<port> (default port: 7010). This provides a web interface to inspect the type inference:

• Search: Search for methods to visualize their IR dependency graphs
• Graph Visualization: Interactive dependency graph

This is useful for understanding how TypeGuessr analyzes your codebase and debugging type inference issues.

Development

After checking out the repo, run bin/setup to install dependencies. Then, run bundle exec rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/riseshia/type-guessr.