Crate forge_lint

Linter (lint)

Solidity linter for identifying potential errors, vulnerabilities, gas optimizations, and style guide violations. It helps enforce best practices and improve code quality within Foundry projects.

Supported Lints

forge-lint includes rules across several categories:

• High Severity:
  • incorrect-shift: Warns against shift operations where operands might be in the wrong order.
• Medium Severity:
  • divide-before-multiply: Warns against performing division before multiplication in the same expression, which can cause precision loss.
• Informational / Style Guide:
  • pascal-case-struct: Flags for struct names not adhering to PascalCase.
  • mixed-case-function: Flags for function names not adhering to mixedCase.
  • mixed-case-variable: Flags for mutable variable names not adhering to mixedCase.
  • screaming-snake-case-const: Flags for constant variable names not adhering to SCREAMING_SNAKE_CASE.
  • screaming-snake-case-immutable: Flags for immutable variable names not adhering to SCREAMING_SNAKE_CASE.
• Gas Optimizations:
  • asm-keccak256: Recommends using inline assembly for keccak256 for potential gas savings.

Configuration

The behavior of the SolidityLinter can be customized with the following options:

Option	Default	Description
with_severity	None	Filters active lints by their severity (High, Med, Low, Info, Gas). None means all severities.
with_lints	None	Specifies a list of SolLint instances to include. Overrides severity filter if a lint matches.
without_lints	None	Specifies a list of SolLint instances to exclude, even if they match other criteria.
with_description	true	Whether to include the lint’s description in the diagnostic output.
with_json_emitter	false	If true, diagnostics are output in rustc-compatible JSON format; otherwise, human-readable text.

Contributing

Check out the foundry contribution guide.

Guidelines for contributing to forge lint:

Opening an issue

1. Create a short concise title describing an issue.
   • Bad Title Examples

     Forge lint does not work
     Forge lint breaks
     Forge lint unexpected behavior

   • Good Title Examples

     Forge lint does not flag incorrect shift operations

2. Fill in the issue template fields that include foundry version, platform & component info.
3. Provide the code snippets showing the current & expected behaviors.
4. If it’s a feature request, specify why this feature is needed.
5. Besides the default label (T-Bug for bugs or T-feature for features), add C-forge and Cmd-forge-fmt labels.

Fixing A Bug

1. Specify an issue that is being addressed in the PR description.
2. Add a note on the solution in the PR description.
3. Add a test case to lint/testdata that specifically demonstrates the bug and is fixed by your changes. Ensure all tests pass.

Developing a New Lint Rule

Check the dev docs for a full implementation guide.

Modules

linter

sol

Macros

declare_forge_lint

Macro for defining lints and relevant metadata for the Solidity linter.

register_lints

Registers Solidity linter passes with their corresponding SolLint.