solhint-plugin-wonderland/rules/non-state-vars-leading-underscore.js

This [Solhint](https://github.com/protofire/solhint/) plugin provides [Wonderland](https://github.com/defi-wonderland) custom rules.

const BaseChecker = require('solhint/lib/rules/base-checker')
const naming = require('solhint/lib/common/identifier-naming')

const DEFAULT_SEVERITY = 'warn'

const ruleId = 'non-state-vars-leading-underscore'
const meta = {
  type: 'naming',
  docs: {
    description: 'Non state variable names must start with a single underscore.',
    category: 'Style Guide Rules'
  },
  isDefault: true,
  recommended: true,
  defaultSetup: [DEFAULT_SEVERITY],
}

class NonStateVarsLeadingUnderscoreChecker extends BaseChecker {
  constructor(reporter) {
    super(reporter, ruleId, meta)
  }

  StateVariableDeclaration() {
    this.inStateVariableDeclaration = true
  }
  
  'StateVariableDeclaration:exit'() {
    this.inStateVariableDeclaration = false
  }
  
  StructDefinition(node) {
    this.inStructDefinition = true
  }
  
  'StructDefinition:exit'() {
    this.inStructDefinition = false
  }

  VariableDeclaration(node) {
    if (!this.inStateVariableDeclaration) {
      const shouldHaveLeadingUnderscore = !this.inStructDefinition;
      this.validateName(node, shouldHaveLeadingUnderscore);
    }
  }

  validateName(node, shouldHaveLeadingUnderscore) {
    if (node.name === null) {
      return
    }

    if (naming.hasLeadingUnderscore(node.name) !== shouldHaveLeadingUnderscore) {
      this._error(node, node.name, shouldHaveLeadingUnderscore)
    }
  }

  _error(node, name, shouldHaveLeadingUnderscore) {
    this.error(
      node,
      `'${name}' ${shouldHaveLeadingUnderscore ? 'should' : 'should not'} start with _`
    )
  }
}

module.exports = NonStateVarsLeadingUnderscoreChecker