gleam-lang/gleam

Code action to generate new type

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#5389 opened on Feb 23, 2026

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 (6 comments) (0 reactions) (0 assignees)Rust (21,417 stars) (960 forks)batch import
help wanted

Description

The language server already allows to create new functions when needed. It would be nice if it allowed to do the same thing with types too. For example:

type Wibble {
  Wibble(Wobble)
//       ^^^^^^ Doesn't exist, trigger code action
}

type Wibble {
  Wibble(Wobble)
}

+ type Wobble

Contributor guide

Tech stack
rust
Domain
developer experiencetooling
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
fresh
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
Rust programmingGleam languageLanguage Server Protocol
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60
Research direction
Look at the existing code action implementation for generating functions in the Gleam language server (likely in src/lsp/ or similar). Identify how the language server detects undefined types and triggers code actions. Add a new code action for generating a type definition (like the function generation but for types). Check the issue comments for any specific suggestions or examples. The Gleam repository is at github.com/gleam lang/gleam; the LSP code is in Rust.