Add vue/no-multiple-slot-args rule.

docs/rules/README.md

@@ -145,6 +145,7 @@ Enforce all the rules in this category, as well as all higher priority rules, wi
 |:--------|:------------|:---|
 | [vue/attributes-order](./attributes-order.md) | enforce order of attributes | :wrench: |
 | [vue/component-tags-order](./component-tags-order.md) | enforce order of component top-level elements |  |
+| [vue/no-multiple-slot-args](./no-multiple-slot-args.md) | disallow to pass multiple arguments to scoped slots |  |
 | [vue/no-v-html](./no-v-html.md) | disallow use of v-html to prevent XSS attack |  |
 | [vue/order-in-components](./order-in-components.md) | enforce order of properties in components | :wrench: |
 | [vue/this-in-template](./this-in-template.md) | disallow usage of `this` in template |  |
@@ -252,6 +253,7 @@ Enforce all the rules in this category, as well as all higher priority rules, wi
 |:--------|:------------|:---|
 | [vue/attributes-order](./attributes-order.md) | enforce order of attributes | :wrench: |
 | [vue/component-tags-order](./component-tags-order.md) | enforce order of component top-level elements |  |
+| [vue/no-multiple-slot-args](./no-multiple-slot-args.md) | disallow to pass multiple arguments to scoped slots |  |
 | [vue/no-v-html](./no-v-html.md) | disallow use of v-html to prevent XSS attack |  |
 | [vue/order-in-components](./order-in-components.md) | enforce order of properties in components | :wrench: |
 | [vue/this-in-template](./this-in-template.md) | disallow usage of `this` in template |  |

docs/rules/no-multiple-slot-args.md

@@ -0,0 +1,49 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/no-multiple-slot-args
+description: disallow to pass multiple arguments to scoped slots
+---
+# vue/no-multiple-slot-args
+> disallow to pass multiple arguments to scoped slots
+
+- :gear: This rule is included in `"plugin:vue/vue3-recommended"` and `"plugin:vue/recommended"`.
+
+## :book: Rule Details
+
+This rule disallows to pass multiple arguments to scoped slots.  
+In details, it reports call expressions if a call of `this.$scopedSlots` members has 2 or more arguments.
+
+<eslint-code-block :rules="{'vue/no-multiple-slot-args': ['error']}">
+
+```vue
+<script>
+export default {
+  render(h) {
+    /* ✓ GOOD */
+    var children = this.$scopedSlots.default()
+    var children = this.$scopedSlots.default(foo)
+    var children = this.$scopedSlots.default({ foo, bar })
+
+    /* ✗ BAD */
+    var children = this.$scopedSlots.default(foo, bar)
+    var children = this.$scopedSlots.default(...foo)
+  }
+}
+</script>
+```
+
+</eslint-code-block>
+
+## :wrench: Options
+
+Nothing.
+
+## :books: Further reading
+
+- [vuejs/vue#9468](https://github.com/vuejs/vue/issues/9468#issuecomment-462210146)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/no-multiple-slot-args.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/no-multiple-slot-args.js)

lib/configs/recommended.js

@@ -8,6 +8,7 @@ module.exports = {
   rules: {
     'vue/attributes-order': 'warn',
     'vue/component-tags-order': 'warn',
+    'vue/no-multiple-slot-args': 'warn',
     'vue/no-v-html': 'warn',
     'vue/order-in-components': 'warn',
     'vue/this-in-template': 'warn'

lib/configs/vue3-recommended.js

@@ -8,6 +8,7 @@ module.exports = {
   rules: {
     'vue/attributes-order': 'warn',
     'vue/component-tags-order': 'warn',
+    'vue/no-multiple-slot-args': 'warn',
     'vue/no-v-html': 'warn',
     'vue/order-in-components': 'warn',
     'vue/this-in-template': 'warn'

lib/index.js

@@ -70,6 +70,7 @@ module.exports = {
     'no-irregular-whitespace': require('./rules/no-irregular-whitespace'),
     'no-lifecycle-after-await': require('./rules/no-lifecycle-after-await'),
     'no-multi-spaces': require('./rules/no-multi-spaces'),
+    'no-multiple-slot-args': require('./rules/no-multiple-slot-args'),
     'no-multiple-template-root': require('./rules/no-multiple-template-root'),
     'no-mutating-props': require('./rules/no-mutating-props'),
     'no-parsing-error': require('./rules/no-parsing-error'),

lib/rules/no-multiple-slot-args.js

@@ -0,0 +1,127 @@
+/**
+ * @author Yosuke Ota
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const utils = require('../utils')
+const { findVariable } = require('eslint-utils')
+
+/**
+ * @typedef {import('vue-eslint-parser').AST.ESLintMemberExpression} MemberExpression
+ * @typedef {import('vue-eslint-parser').AST.ESLintIdentifier} Identifier
+ */
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description: 'disallow to pass multiple arguments to scoped slots',
+      categories: ['vue3-recommended', 'recommended'],
+      url: 'https://eslint.vuejs.org/rules/no-multiple-slot-args.html'
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      unexpected: 'Unexpected multiple arguments.',
+      unexpectedSpread: 'Unexpected spread argument.'
+    }
+  },
+
+  create(context) {
+    /**
+     * Verify the given node
+     * @param {MemberExpression | Identifier} node The node to verify
+     */
+    function verify(node) {
+      const parent = node.parent
+
+      if (
+        parent.type === 'VariableDeclarator' &&
+        parent.id.type === 'Identifier'
+      ) {
+        // const foo = this.$scopedSlots.foo
+        verifyReferences(parent.id)
+        return
+      }
+
+      if (
+        parent.type === 'AssignmentExpression' &&
+        parent.right === node &&
+        parent.left.type === 'Identifier'
+      ) {
+        // foo = this.$scopedSlots.foo
+        verifyReferences(parent.left)
+        return
+      }
+
+      if (parent.type !== 'CallExpression' || parent.arguments.includes(node)) {
+        return
+      }
+
+      if (!parent.arguments.length) {
+        return
+      }
+      if (parent.arguments.length > 1) {
+        context.report({
+          node: parent.arguments[1],
+          messageId: 'unexpected'
+        })
+      }
+      if (parent.arguments[0].type === 'SpreadElement') {
+        context.report({
+          node: parent.arguments[0],
+          messageId: 'unexpectedSpread'
+        })
+      }
+    }
+    /**
+     * Verify the references of the given node.
+     * @param {Identifier} node The node to verify
+     */
+    function verifyReferences(node) {
+      // @ts-ignore
+      const variable = findVariable(context.getScope(), node)
+      if (!variable) {
+        return
+      }
+      for (const reference of variable.references) {
+        if (!reference.isRead()) {
+          continue
+        }
+        /** @type {Identifier} */
+        const id = reference.identifier
+        verify(id)
+      }
+    }
+
+    return utils.defineVueVisitor(context, {
+      /** @param {MemberExpression} node */
+      MemberExpression(node) {
+        const object = node.object
+        if (object.type !== 'MemberExpression') {
+          return
+        }
+        if (
+          object.property.type !== 'Identifier' ||
+          (object.property.name !== '$slots' &&
+            object.property.name !== '$scopedSlots')
+        ) {
+          return
+        }
+        if (!utils.isThis(object.object, context)) {
+          return
+        }
+        verify(node)
+      }
+    })
+  }
+}

tests/lib/rules/no-multiple-slot-args.js

@@ -0,0 +1,164 @@
+/**
+ * @author Yosuke Ota
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const rule = require('../../../lib/rules/no-multiple-slot-args')
+
+const RuleTester = require('eslint').RuleTester
+
+// ------------------------------------------------------------------------------
+// Tests
+// ------------------------------------------------------------------------------
+
+const ruleTester = new RuleTester({
+  parser: require.resolve('vue-eslint-parser'),
+  parserOptions: { ecmaVersion: 2018, sourceType: 'module' }
+})
+ruleTester.run('no-multiple-slot-args', rule, {
+  valid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          var children = this.$scopedSlots.default()
+          var children = this.$scopedSlots.foo(foo)
+          const bar = this.$scopedSlots.bar
+          bar(foo)
+        }
+      }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          unknown.$scopedSlots.default(foo, bar)
+        }
+      }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          // for Vue3
+          var children = this.$slots.default()
+          var children = this.$slots.foo(foo)
+          const bar = this.$slots.bar
+          bar(foo)
+        }
+      }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          this.$foo.default(foo, bar)
+        }
+      }
+      </script>
+      `
+    }
+  ],
+
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          this.$scopedSlots.default(foo, bar)
+          this.$scopedSlots.foo(foo, bar)
+        }
+      }
+      </script>
+      `,
+      errors: [
+        {
+          message: 'Unexpected multiple arguments.',
+          line: 5,
+          column: 42,
+          endLine: 5,
+          endColumn: 45
+        },
+        {
+          message: 'Unexpected multiple arguments.',
+          line: 6,
+          column: 38,
+          endLine: 6,
+          endColumn: 41
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          let children
+
+          this.$scopedSlots.default(foo, { bar })
+
+          children = this.$scopedSlots.foo
+          if (children) children(...foo)
+        }
+      }
+      </script>
+      `,
+      errors: [
+        {
+          message: 'Unexpected multiple arguments.',
+          line: 7,
+          column: 42,
+          endLine: 7,
+          endColumn: 49
+        },
+        {
+          message: 'Unexpected spread argument.',
+          line: 10,
+          column: 34,
+          endLine: 10,
+          endColumn: 40
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        render (h) {
+          // for Vue3
+          this.$slots.default(foo, bar)
+          this.$slots.foo(foo, bar)
+        }
+      }
+      </script>
+      `,
+      errors: [
+        'Unexpected multiple arguments.',
+        'Unexpected multiple arguments.'
+      ]
+    }
+  ]
+})