HLint review
A focused Haskell linter for style guidance, custom hints, and refactoring support.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
HLint is an open-source command-line linter for Haskell code, available on Windows, macOS, and Linux. It analyzes source files for redundant code patterns, style issues, function combinations, and expressions that can be simplified. Its audience is Haskell developers who want actionable refactoring suggestions alongside conventional lint feedback, particularly teams working with Haskell language extensions or C preprocessor input.
Its standout capability is the combination of suggestions, custom rules, and supported automatic refactoring. Developers can configure built-in hints, add project-specific hints, and apply supported suggestions with the --refactor option. HLint also generates interactive HTML reports, giving teams a separate way to review findings. The refactoring scope is selective rather than universal: not every hint supports automatic application, so developers should treat the feature as targeted assistance rather than a complete code transformation system.
HLint fits established Haskell workflows through Haskell Language Server, a GHC plugin, Code Climate, Danger, Restyled, CircleCI, GitHub Actions, Vim, Emacs, and Atom. It supports CI workflows and editor or Haskell IDE integrations, which makes it suitable for individual development as well as automated project checks. Its one-language focus is a strength for Haskell teams but limits its usefulness in mixed-language environments. HLint is a good choice for Haskell-focused style and refactoring guidance; choose another linter when security rules or broader language coverage are required.
HLint pros and cons
- Where it wins
- Suggests simpler expressions and alternative Haskell functions
- Applies supported suggestions with --refactor
- Supports custom hints, HTML reports, CI, and IDE integrations
- Where it doesn't
- Supports only Haskell
- Does not provide security rules
- Automatic refactoring is unavailable for some hints
HLint fact sheet, pricing and score →
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