Weeder is a command-line utility for Haskell that performs whole-program dead-code analysis.
It works with `.hie` files generated by GHC, builds a dependency graph of declarations, and traverses that graph from configurable roots to identify code that is no longer reachable. The tool is designed for real-world Haskell projects and can be used with Cabal, Stack, and Nix-based workflows to help developers locate and remove unused declarations across module boundaries.
This is free and open source software.
Key Features
- Analyzes whole Haskell programs using GHC-generated `.hie` files.
- Finds unreachable declarations across module boundaries, not just within a single module.
- Uses a TOML configuration file with options such as `roots`, `root-instances`, `root-modules`, `type-class-roots`, and `unused-types`.
- Can generate a default configuration automatically with the `–write-default-config` flag.
- Supports analysis of type class instances and optional detection of unused types.
- Works with Cabal, Stack, and Nix-based development workflows.
- Offers parallel analysis support and distinct exit codes for common success and failure cases.
Website: github.com/ocharles/weeder
Support:
Developer: Ollie Charles
License: BSD 3-Clause “New” or “Revised” License
Weeder is written in Haskell. Learn Haskell with our recommended free books and free tutorials.
Related Software
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| stylish-haskell | Simple Haskell code prettifier |
| hindent | Extensible Haskell pretty printer |
| Floskell | Flexible Haskell source code pretty printer |
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