Completion Plugins for Non-JavaScript Languages: What's Available for Rust, Go, and Dart

Written By:
Founder & CTO
July 9, 2025

Code completion is a foundational capability in modern IDEs, streamlining developer workflows and reducing cognitive load during programming. For JavaScript and TypeScript, this space is mature, with feature-rich extensions backed by robust ecosystems. However, for non-JavaScript languages such as Rust, Go, and Dart, the tooling landscape is historically fragmented, requiring more explicit configuration and language-specific support. These languages often have unique syntactic and semantic rules, and generic language tooling falls short when used in production-scale projects. Completion plugins that understand the idioms, typing rules, and module systems of these languages are vital for maximizing efficiency and reducing error-prone development cycles.

This blog offers a technically detailed exploration of the available completion plugins for Rust, Go, and Dart, focusing on the developer experience, architecture of each plugin, performance benchmarks, language feature coverage, and cross-editor compatibility.

Rust: Intelligent Completion with rust-analyzer
Primary Plugin: rust-analyzer

The primary tool for intelligent Rust development is rust-analyzer, a language server that has become the community's standard for advanced IDE support. Unlike its predecessor, RLS, which relied on rustc, rust-analyzer is built from the ground up to provide fast, incremental feedback by directly parsing Rust code and performing semantic analysis in a lightweight manner.

How rust-analyzer Works

At the core, rust-analyzer uses a high-performance incremental compiler architecture that leverages rowan for syntax tree construction and chalk for trait solving. This allows the tool to offer near-instant completions, even on large, multi-crate projects. The plugin maintains an in-memory representation of the abstract syntax tree and tracks dependencies across the workspace, enabling accurate contextual suggestions, including trait methods, macros, and type-based field access.

Features
  • Symbol-aware autocompletion including traits, methods, and macros
  • Real-time type inference across function boundaries
  • Inlay hints showing inferred types and lifetime elision
  • Inline documentation through rustdoc extraction
  • Auto-import suggestions based on context
  • Code actions such as extracting variables, converting match arms, and implementing missing trait methods
  • Diagnostic feedback and quick-fixes
  • Integration with clippy and cargo check for static analysis on save
Editor Support
  • VSCode: Rust Analyzer official extension with LSP integration and support for multi-workspace crates, custom target triples, and inline cargo output
  • Neovim / Vim: Support through nvim-lspconfig and rust-tools.nvim, enabling advanced features like hover actions, lens support, and runnables
  • JetBrains CLion / IntelliJ Rust: Native plugin that mimics rust-analyzer’s capabilities, though rust-analyzer integration is now a first-class option in IntelliJ
Developer Tips

For optimal usage, developers should configure rust-analyzer to enable checkOnSave with Clippy to surface potential issues during development, especially when dealing with unsafe code or complex lifetimes. Additionally, enabling procMacro.enable allows better support for codebases leveraging procedural macros such as serde and tokio_macros.

Go: Production-Grade Autocompletion with gopls
Primary Plugin: gopls (Go Language Server)

The Go language team officially maintains gopls, a robust and scalable language server offering powerful completion features. It is designed to serve as the backend for all modern Go IDE integrations, and it is tightly coupled with the Go compiler toolchain. Unlike ad hoc completion plugins, gopls uses the Go build system and standard Go packages to offer accurate and context-aware suggestions.

How gopls Works

gopls builds an internal representation of the Go workspace by parsing module dependencies and utilizing type information from the go/types package. It uses a caching strategy to minimize redundant analysis and supports incremental parsing to ensure responsiveness in large codebases. It integrates seamlessly with Go modules and recognizes nested module configurations.

Features
  • Code completions for struct fields, methods, interfaces, packages, and standard library elements
  • Intelligent documentation via go doc integration
  • On-the-fly error detection using go vet, go build, and staticcheck
  • Advanced refactoring tools including method extraction, renaming, and import pruning
  • Jump to definition, references, type definition, and implementation
  • Auto-import management and unused import removal
  • Workspace symbol indexing
Editor Support
  • VSCode: Go extension that wraps gopls, offering real-time diagnostics, debug support with Delve, and automatic module management
  • Neovim / Vim: Configurable with nvim-lspconfig and supported by community plugins like go.nvim
  • GoLand (JetBrains): Provides native analysis without gopls, but can integrate it for consistency across environments
Developer Tips

Enable staticcheck and analyses in your LSP settings to catch performance issues and potential bugs during development. In team environments, enable codelenses for test coverage insights and consistent formatting with gofmt. Developers working on monorepos with multiple Go modules should ensure gopls is configured with correct workspace root detection.

Dart: Flutter-Aware Completion with the Dart Analysis Server
Primary Plugin: Dart Analysis Server

The Dart Analysis Server is bundled with the Dart SDK and offers full-featured support for both Dart and Flutter development. It provides real-time feedback on code correctness, suggestions, refactoring tools, and widget-aware completions for Flutter developers. It is built with tight integration into the Dart type system and supports asynchronous and reactive patterns.

How Dart Analysis Server Works

The server operates by creating a complete model of the Dart program, building symbol tables, and performing static type analysis. It supports incremental updates to the abstract syntax tree and emits completion suggestions based on scope, context, and type signatures. It also leverages Flutter introspection metadata to provide widget-specific enhancements.

Features
  • Symbol-based completions including Dart SDK, third-party packages, and project-specific classes
  • Live hints for function parameters, named arguments, and Flutter widget constructors
  • Auto-import suggestions with fully qualified path resolution
  • Hot reload-aware context management in Flutter projects
  • Refactorings such as widget extraction, method movement, and renaming
  • Real-time error checking and lint rule enforcement using analysis_options.yaml
  • Completion suggestions within build methods and widget trees
Editor Support
  • VSCode: Dart and Flutter extensions with tight integration into DevTools, offering in-editor widget previews, performance overlays, and timeline debugging
  • Android Studio / IntelliJ IDEA: First-party Flutter plugin that integrates with both the Dart and Flutter SDKs, providing the most complete experience
  • Emacs / Vim: Experimental support via LSP bridges, but with fewer UI features
Developer Tips

Developers building Flutter apps should enable dart.completeFunctionCalls for faster UI layout creation. When dealing with stateful widgets or complex widget trees, enabling widget rebuild visualization can highlight performance bottlenecks. For backend Dart development using shelf or aqueduct, the same analysis server offers reliable completion and linting support.

Comparative Analysis: Completion Maturity Across Rust, Go, and Dart

Future Outlook for Completion Tooling in Non-JavaScript Languages

The tooling ecosystems for Rust, Go, and Dart are becoming increasingly sophisticated, driven by growing demand for reliable and scalable backend, systems, and cross-platform mobile development. Completion engines are moving toward deeper semantic understanding, tighter CI/CD integration, and the adoption of AI-assisted refactoring tools.

  • Rust's rust-analyzer is expected to deepen its macro expansion support and provide better performance in workspaces with thousands of files
  • Go's gopls roadmap includes tighter integration with static analysis tools, better debugging support, and remote development optimization
  • Dart's server is expanding support for package-specific completions and enhancing the Flutter DevTools experience with AI-driven widget prediction

Completion plugins will increasingly adopt ML-based approaches to suggest code blocks, identify patterns across teams, and offer contextual documentation sourced from online repositories, RFCs, and community packages.

Conclusion

Rust, Go, and Dart now offer mature, production-grade completion plugins that rival the experience JavaScript developers have long enjoyed. Whether you are building low-level systems in Rust, scalable APIs in Go, or UI-rich mobile applications in Dart, the right completion tooling can drastically improve your productivity and confidence in code quality.

A properly configured development environment, paired with LSP-driven completion plugins, enables developers to write clean, idiomatic, and maintainable code with minimal friction.

Looking for Full-Stack AI Assistance?

For developers looking to extend their capabilities beyond completions into full-stack automation, testing, and deployment, GoCodeo offers an AI-native coding agent that integrates directly with VSCode. It supports multiple languages including Rust, Go, and Dart, and helps streamline the entire development pipeline from idea to deployment.

Visit GoCodeo to explore more advanced tooling for full-stack app generation and deployment.