Add no-deprecated-router-link-tag-prop rule (#1663)

* Add `no-deprecated-router-link-tag-prop` rule

* Fix pylint error at no-deprecated-router-link-tag-prop

* Fix review comments for no-deprecated-router-link-tag-prop

- Use helper functions from utils to get attributes for nodes.
- Add more test cases.
- Handle both kebab-case and PascalCase version of components.

* Update no-deprecated-router-link-tag-prop.md

Co-authored-by: Yosuke Ota <otameshiyo23@gmail.com>

docs/rules/README.md

@@ -302,6 +302,7 @@ For example:
 | [vue/no-bare-strings-in-template](./no-bare-strings-in-template.md) | disallow the use of bare strings in `<template>` |  |
 | [vue/no-boolean-default](./no-boolean-default.md) | disallow boolean defaults | :wrench: |
 | [vue/no-computed-properties-in-data](./no-computed-properties-in-data.md) | disallow accessing computed properties in `data`. |  |
+| [vue/no-deprecated-router-link-tag-prop](./no-deprecated-router-link-tag-prop.md) | disallow using deprecated `tag` property on `RouterLink` (in Vue.js 3.0.0+) |  |
 | [vue/no-deprecated-v-is](./no-deprecated-v-is.md) | disallow deprecated `v-is` directive (in Vue.js 3.1.0+) | :wrench: |
 | [vue/no-duplicate-attr-inheritance](./no-duplicate-attr-inheritance.md) | enforce `inheritAttrs` to be set to `false` when using `v-bind="$attrs"` |  |
 | [vue/no-empty-component-block](./no-empty-component-block.md) | disallow the `<template>` `<script>` `<style>` block to be empty |  |

docs/rules/no-deprecated-router-link-tag-prop.md

@@ -0,0 +1,91 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/no-deprecated-router-link-tag-prop
+description: disallow using deprecated `tag` property on `RouterLink` (in Vue.js 3.0.0+)
+---
+# vue/no-deprecated-router-link-tag-prop
+
+> disallow using deprecated `tag` property on `RouterLink` (in Vue.js 3.0.0+)
+
+- :exclamation: <badge text="This rule has not been released yet." vertical="middle" type="error"> ***This rule has not been released yet.*** </badge>
+
+## :book: Rule Details
+
+This rule reports deprecated the `tag` attribute on `RouterLink` elements (removed in Vue.js v3.0.0+).
+
+<eslint-code-block :rules="{'vue/no-deprecated-router-link-tag-prop': ['error']}">
+
+```vue
+<template>
+  <!-- ✓ GOOD -->
+  <RouterLink to="/">Home</RouterLink>
+  <router-link to="/">Home</router-link>
+
+  <RouterLink to="/">
+    <div>Home</div>
+  </RouterLink>
+
+  <router-link to="/">
+    <div>Home</div>
+  </router-link>
+
+  <NuxtLink tag="div" to="/">Home</NuxtLink>
+  <nuxt-link tag="div" to="/">Home</nuxt-link>
+
+  <!-- ✗ BAD -->
+  <RouterLink tag="div" to="/">Home</RouterLink>
+  <router-link tag="div" to="/">Home</router-link>
+  <RouterLink :tag="someVariable" to="/">Home</RouterLink>
+  <router-link :tag="someVariable" to="/">Home</router-link>
+</template>
+```
+
+</eslint-code-block>
+
+## :wrench: Options
+
+```json
+{
+  "vue/no-deprecated-router-link-tag-prop": ["error", {
+    "components": ['RouterLink']
+  }]
+}
+```
+
+- `components` (`string[]`) ... Component names which will be checked with the `tag` attribute. default `['RouterLink']`.
+
+Note: this rule will check both `kebab-case` and `PascalCase` versions of the
+given component names.
+
+### `{ "components": ['RouterLink', 'NuxtLink'] }`
+
+<eslint-code-block :rules="{'vue/no-deprecated-router-link-tag-prop': ['error', {'components': ['RouterLink', 'NuxtLink']}]}">
+
+```vue
+<template>
+  <!-- ✗ BAD -->
+  <RouterLink tag="div" to="/">Home</RouterLink>
+  <router-link tag="div" to="/">Home</router-link>
+
+  <RouterLink :tag="someVariable" to="/">Home</RouterLink>
+  <router-link :tag="someVariable" to="/">Home</router-link>
+
+  <NuxtLink tag="div" to="/">Home</NuxtLink>
+  <nuxt-link tag="div" to="/">Home</nuxt-link>
+
+  <NuxtLink :tag="someVariable" to="/">Home</NuxtLink>
+  <nuxt-link :tag="someVariable" to="/">Home</nuxt-link>
+</template>
+```
+
+</eslint-code-block>
+
+## :books: Further Reading
+
+- [Vue RFCs - 0021-router-link-scoped-slot](https://github.com/vuejs/rfcs/blob/master/active-rfcs/0021-router-link-scoped-slot.md)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/no-deprecated-router-link-tag-prop.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/no-deprecated-router-link-tag-prop.js)

lib/index.js

@@ -71,6 +71,7 @@ module.exports = {
     'no-deprecated-html-element-is': require('./rules/no-deprecated-html-element-is'),
     'no-deprecated-inline-template': require('./rules/no-deprecated-inline-template'),
     'no-deprecated-props-default-this': require('./rules/no-deprecated-props-default-this'),
+    'no-deprecated-router-link-tag-prop': require('./rules/no-deprecated-router-link-tag-prop'),
     'no-deprecated-scope-attribute': require('./rules/no-deprecated-scope-attribute'),
     'no-deprecated-slot-attribute': require('./rules/no-deprecated-slot-attribute'),
     'no-deprecated-slot-scope-attribute': require('./rules/no-deprecated-slot-scope-attribute'),

lib/rules/no-deprecated-router-link-tag-prop.js

@@ -0,0 +1,103 @@
+/**
+ * @author Marton Csordas
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+// ------------------------------------------------------------------------------
+// Requirements
+// ------------------------------------------------------------------------------
+
+const utils = require('../utils')
+const casing = require('../utils/casing')
+
+// --------------------------------------------------------------------------
+// Helpers
+// --------------------------------------------------------------------------
+
+/** @param {RuleContext} context */
+function getComponentNames(context) {
+  let components = ['RouterLink']
+
+  if (context.options[0] && context.options[0].components) {
+    components = context.options[0].components
+  }
+
+  return components.reduce((prev, curr) => {
+    prev.add(casing.kebabCase(curr))
+    prev.add(casing.pascalCase(curr))
+    return prev
+  }, new Set())
+}
+
+// ------------------------------------------------------------------------------
+// Rule Definition
+// ------------------------------------------------------------------------------
+
+module.exports = {
+  meta: {
+    type: 'problem',
+    docs: {
+      description:
+        'disallow using deprecated `tag` property on `RouterLink` (in Vue.js 3.0.0+)',
+      categories: undefined,
+      url: 'https://eslint.vuejs.org/rules/no-deprecated-router-link-tag-prop.html'
+    },
+    fixable: null,
+    schema: [
+      {
+        type: 'object',
+        properties: {
+          components: {
+            type: 'array',
+            items: {
+              type: 'string'
+            },
+            uniqueItems: true,
+            minItems: 1
+          }
+        }
+      }
+    ],
+    messages: {
+      deprecated:
+        "'tag' property on '{{element}}' component is deprecated. Use scoped slots instead."
+    }
+  },
+  /** @param {RuleContext} context */
+  create(context) {
+    const components = getComponentNames(context)
+
+    return utils.defineTemplateBodyVisitor(context, {
+      VElement(node) {
+        if (!components.has(node.rawName)) return
+
+        /** @type VIdentifier | null */
+        let tagKey = null
+
+        const tagAttr = utils.getAttribute(node, 'tag')
+        if (tagAttr) {
+          tagKey = tagAttr.key
+        } else {
+          const directive = utils.getDirective(node, 'bind', 'tag')
+          if (directive) {
+            const arg = directive.key.argument
+            if (arg && arg.type === 'VIdentifier') {
+              tagKey = arg
+            }
+          }
+        }
+
+        if (tagKey) {
+          context.report({
+            node: tagKey,
+            messageId: 'deprecated',
+            data: {
+              element: node.rawName
+            }
+          })
+        }
+      }
+    })
+  }
+}