hx check

Type check the project without building.

Synopsis

hx check [OPTIONS]

Description

The check command runs the type checker on your project without performing a full compilation. This is faster than hx build and is useful for quick feedback during development.

It’s equivalent to running cabal build --ghc-options="-fno-code".

Options

    --lib               Check only the library
    --exe <NAME>        Check only the specified executable
    --test              Check only tests
    --all               Check all components
    --backend <BACKEND> Compiler backend [ghc, bhc]
-v, --verbose           Show detailed output

Examples

Check All Components

hx check

Check Library Only

hx check --lib

Check Specific Executable

hx check --exe my-app

Check Tests

hx check --test

When to Use Check vs Build

Use hx check when:

You want fast feedback on type errors
You’re iterating on code design
You don’t need to run the resulting binary
You’re using an IDE/editor integration

Use hx build when:

You need to run the program
You want to catch linker errors
You’re preparing for deployment

Performance

hx check is typically 2-5x faster than hx build because it:

Skips code generation
Skips object file creation
Skips linking

Integration with Editors

Many editors use hx check or similar for real-time feedback:

VS Code with HLS

HLS provides real-time type checking. You can also run:

hx check

Vim/Neovim

With ALE or coc.nvim:

" Use hx check for linting
let g:ale_linters = {'haskell': ['hx']}

Configuration

[check]
# Enable all warnings
warnings = ["all"]

# Treat warnings as errors
werror = false