From b73b57d466116d5e75afad9ff552fd7152dc4986 Mon Sep 17 00:00:00 2001
From: ItMaga <m-chemurziev@ya.ru>
Date: Mon, 13 Nov 2023 16:25:43 +0300
Subject: [PATCH 1/3] add `vue/no-unused-emit-declarations` rule

---
 docs/rules/index.md                           |   1 +
 docs/rules/no-unused-emit-declarations.md     |  59 ++
 docs/rules/require-explicit-emits.md          |   4 +
 lib/index.js                                  |   1 +
 lib/rules/no-unused-emit-declarations.js      | 334 +++++++++
 .../lib/rules/no-unused-emit-declarations.js  | 693 ++++++++++++++++++
 6 files changed, 1092 insertions(+)
 create mode 100644 docs/rules/no-unused-emit-declarations.md
 create mode 100644 lib/rules/no-unused-emit-declarations.js
 create mode 100644 tests/lib/rules/no-unused-emit-declarations.js

diff --git a/docs/rules/index.md b/docs/rules/index.md
index 224cddc7d..a7d3047a3 100644
--- a/docs/rules/index.md
+++ b/docs/rules/index.md
@@ -251,6 +251,7 @@ For example:
 | [vue/no-undef-components](./no-undef-components.md) | disallow use of undefined components in `<template>` |  | :hammer: |
 | [vue/no-undef-properties](./no-undef-properties.md) | disallow undefined properties |  | :hammer: |
 | [vue/no-unsupported-features](./no-unsupported-features.md) | disallow unsupported Vue.js syntax on the specified version | :wrench: | :hammer: |
+| [vue/no-unused-emit-declarations](./no-unused-emit-declarations.md) | disallow unused emit declarations |  | :hammer: |
 | [vue/no-unused-properties](./no-unused-properties.md) | disallow unused properties |  | :hammer: |
 | [vue/no-unused-refs](./no-unused-refs.md) | disallow unused refs |  | :hammer: |
 | [vue/no-use-v-else-with-v-for](./no-use-v-else-with-v-for.md) | disallow using `v-else-if`/`v-else` on the same element as `v-for` |  | :hammer: |
diff --git a/docs/rules/no-unused-emit-declarations.md b/docs/rules/no-unused-emit-declarations.md
new file mode 100644
index 000000000..a6c938624
--- /dev/null
+++ b/docs/rules/no-unused-emit-declarations.md
@@ -0,0 +1,59 @@
+---
+pageClass: rule-details
+sidebarDepth: 0
+title: vue/no-unused-emit-declarations
+description: disallow unused emit declarations
+---
+# vue/no-unused-emit-declarations
+
+> disallow unused emit declarations
+
+- :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 is aimed at eliminating unused emit declarations.
+
+<eslint-code-block :rules="{'vue/no-unused-emit-declarations': ['error']}">
+
+```vue
+<!-- ✗ BAD -->
+<script>
+  export default {
+    emits: ['foo'],
+  }
+</script>
+```
+
+</eslint-code-block>
+
+<eslint-code-block :rules="{'vue/no-unused-emit-declarations': ['error']}">
+
+```vue
+<!-- ✓ GOOD -->
+<script>
+  export default {
+    emits: ['foo'],
+    methods: {
+      foo() {
+        this.$emit('foo')
+      },
+    },
+  }
+</script>
+```
+
+</eslint-code-block>
+
+## :wrench: Options
+
+Nothing.
+
+## :couple: Related Rules
+
+- [vue/require-explicit-emits](./require-explicit-emits.md)
+
+## :mag: Implementation
+
+- [Rule source](https://github.com/vuejs/eslint-plugin-vue/blob/master/lib/rules/no-unused-emit-declarations.js)
+- [Test source](https://github.com/vuejs/eslint-plugin-vue/blob/master/tests/lib/rules/no-unused-emit-declarations.js)
diff --git a/docs/rules/require-explicit-emits.md b/docs/rules/require-explicit-emits.md
index 6d681c551..f7ce60dd6 100644
--- a/docs/rules/require-explicit-emits.md
+++ b/docs/rules/require-explicit-emits.md
@@ -109,6 +109,10 @@ export default {
 
 </eslint-code-block>
 
+## :couple: Related Rules
+
+- [vue/no-unused-emit-declarations](./no-unused-emit-declarations.md)
+
 ## :books: Further Reading
 
 - [Guide - Custom Events / Defining Custom Events](https://v3.vuejs.org/guide/component-custom-events.html#defining-custom-events)
diff --git a/lib/index.js b/lib/index.js
index edbe34a2c..0f3dcba27 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -147,6 +147,7 @@ module.exports = {
     'no-undef-properties': require('./rules/no-undef-properties'),
     'no-unsupported-features': require('./rules/no-unsupported-features'),
     'no-unused-components': require('./rules/no-unused-components'),
+    'no-unused-emit-declarations': require('./rules/no-unused-emit-declarations'),
     'no-unused-properties': require('./rules/no-unused-properties'),
     'no-unused-refs': require('./rules/no-unused-refs'),
     'no-unused-vars': require('./rules/no-unused-vars'),
diff --git a/lib/rules/no-unused-emit-declarations.js b/lib/rules/no-unused-emit-declarations.js
new file mode 100644
index 000000000..71ac91a64
--- /dev/null
+++ b/lib/rules/no-unused-emit-declarations.js
@@ -0,0 +1,334 @@
+/**
+ * @author ItMaga
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const { findVariable } = require('@eslint-community/eslint-utils')
+const utils = require('../utils')
+
+/**
+ * @typedef {import('../utils').ComponentEmit} ComponentEmit
+ * @typedef {import('../utils').VueObjectData} VueObjectData
+ */
+
+/**
+ * @typedef {object} SetupContext
+ * @property {Set<Identifier>} contextReferenceIds
+ * @property {Set<Identifier>} emitReferenceIds
+ */
+
+/**
+ * @typedef {object} NameWithLoc
+ * @property {string} name
+ * @property {SourceLocation} loc
+ * @property {Range} range
+ */
+
+/**
+ * Get the name param node from the given CallExpression
+ * @param {CallExpression} node CallExpression
+ * @returns { NameWithLoc | null }
+ */
+function getNameParamNode(node) {
+  const nameLiteralNode = node.arguments[0]
+  if (nameLiteralNode && utils.isStringLiteral(nameLiteralNode)) {
+    const name = utils.getStringLiteralValue(nameLiteralNode)
+    if (name != null) {
+      return { name, loc: nameLiteralNode.loc, range: nameLiteralNode.range }
+    }
+  }
+
+  return null
+}
+
+/**
+ * Check if the given node is a reference of setup context
+ * @param {Expression | Super | SpreadElement} value
+ * @param {SetupContext} setupContext
+ * @returns {boolean}
+ * */
+function hasReferenceId(value, setupContext) {
+  const { contextReferenceIds, emitReferenceIds } = setupContext
+  return (
+    value.type === 'Identifier' &&
+    (emitReferenceIds.has(value) || contextReferenceIds.has(value))
+  )
+}
+
+module.exports = {
+  meta: {
+    type: 'suggestion',
+    docs: {
+      description: 'disallow unused emit declarations',
+      categories: undefined,
+      url: 'https://eslint.vuejs.org/rules/no-unused-emit-declarations.html'
+    },
+    fixable: null,
+    schema: [],
+    messages: {
+      unused: '`{{name}}` is defined as emit but never used.'
+    }
+  },
+  /** @param {RuleContext} context */
+  create(context) {
+    /** @type {Map<string, ComponentEmit>} */
+    const emitDeclarations = new Map()
+    /** @type {Map<string, Expression>} */
+    const emitCalls = new Map()
+    /** @type {Map<ObjectExpression | Program, SetupContext>} */
+    const setupContexts = new Map()
+    const programNode = context.getSourceCode().ast
+
+    /**
+     * @param {CallExpression} node
+     * */
+    function addEmitCall(node) {
+      const nameParamNode = getNameParamNode(node)
+      if (nameParamNode) {
+        emitCalls.set(nameParamNode.name, node)
+      }
+    }
+    function clearEmits() {
+      emitCalls.clear()
+      emitDeclarations.clear()
+    }
+
+    /**
+     * @param {Expression | SpreadElement} expression
+     * @param {SetupContext} setupContext
+     * @returns {boolean}
+     * */
+    function checkExpressionReference(expression, setupContext) {
+      if (expression.type === 'MemberExpression') {
+        const memObject = utils.skipChainExpression(expression.object)
+        if (hasReferenceId(memObject, setupContext)) {
+          clearEmits()
+          return true
+        }
+      }
+      if (hasReferenceId(expression, setupContext)) {
+        clearEmits()
+        return true
+      }
+      return false
+    }
+
+    /**
+     *
+     * @param {Array<Expression | SpreadElement>} args
+     * @param {SetupContext} setupContext
+     * @returns
+     */
+    function verifyArgumentsReferences(args, setupContext) {
+      for (const argument of args) {
+        if (argument.type === 'ObjectExpression') {
+          for (const property of argument.properties) {
+            if (
+              property.type === 'Property' &&
+              checkExpressionReference(property.value, setupContext)
+            ) {
+              return true
+            }
+          }
+        }
+
+        if (argument.type === 'ArrayExpression') {
+          for (const element of argument.elements) {
+            if (!element) {
+              continue
+            }
+            if (checkExpressionReference(element, setupContext)) {
+              return true
+            }
+          }
+        }
+
+        if (checkExpressionReference(argument, setupContext)) {
+          return true
+        }
+      }
+      return false
+    }
+
+    /**
+     * @param {Expression | Super} callee
+     * @param {Set<Identifier>} referenceIds
+     * @param {CallExpression} node
+     * */
+    function addEmitCallByReference(callee, referenceIds, node) {
+      if (callee.type === 'Identifier' && referenceIds.has(callee)) {
+        addEmitCall(node)
+      }
+    }
+
+    const callVisitor = {
+      /**
+       * @param {CallExpression} node
+       * @param {VueObjectData} [info]
+       */
+      CallExpression(node, info) {
+        const callee = utils.skipChainExpression(node.callee)
+
+        let emit = null
+        if (callee.type === 'MemberExpression') {
+          const name = utils.getStaticPropertyName(callee)
+          if (name === 'emit' || name === '$emit') {
+            emit = { name, member: callee }
+          }
+        }
+
+        const vueDefineNode = info ? info.node : programNode
+        const setupContext = setupContexts.get(vueDefineNode)
+        if (setupContext) {
+          if (
+            callee.parent.type === 'CallExpression' &&
+            callee.parent.arguments &&
+            verifyArgumentsReferences(callee.parent.arguments, setupContext)
+          ) {
+            // skip if the emit passed as argument
+            return
+          }
+
+          const { contextReferenceIds, emitReferenceIds } = setupContext
+          // verify setup(props,{emit}) {emit()}
+          addEmitCallByReference(callee, emitReferenceIds, node)
+          if (emit && emit.name === 'emit') {
+            const memObject = utils.skipChainExpression(emit.member.object)
+            // verify setup(props,context) {context.emit()}
+            addEmitCallByReference(memObject, contextReferenceIds, node)
+          }
+        }
+
+        if (emit && emit.name === '$emit') {
+          const memObject = utils.skipChainExpression(emit.member.object)
+          // verify this.$emit()
+          if (utils.isThis(memObject, context)) {
+            addEmitCall(node)
+          }
+        }
+
+        // verify $emit() in template
+        if (callee.type === 'Identifier' && callee.name === '$emit') {
+          addEmitCall(node)
+        }
+      }
+    }
+
+    return utils.compositingVisitors(
+      utils.defineTemplateBodyVisitor(context, callVisitor),
+      utils.defineVueVisitor(context, {
+        ...callVisitor,
+        onVueObjectEnter(node) {
+          for (const emit of utils.getComponentEmitsFromOptions(node)) {
+            if (emit.emitName) {
+              emitDeclarations.set(emit.emitName, emit)
+            }
+          }
+        },
+        onSetupFunctionEnter(node, { node: vueNode }) {
+          const contextParam = node.params[1]
+          if (!contextParam) {
+            // no arguments
+            return
+          }
+          if (contextParam.type === 'RestElement') {
+            // cannot check
+            return
+          }
+          if (contextParam.type === 'ArrayPattern') {
+            // cannot check
+            return
+          }
+
+          /** @type {Set<Identifier>} */
+          const contextReferenceIds = new Set()
+          /** @type {Set<Identifier>} */
+          const emitReferenceIds = new Set()
+          if (contextParam.type === 'ObjectPattern') {
+            const emitProperty = utils.findAssignmentProperty(
+              contextParam,
+              'emit'
+            )
+            if (!emitProperty) {
+              return
+            }
+            const emitParam = emitProperty.value
+            // `setup(props, {emit})`
+            const variable =
+              emitParam.type === 'Identifier'
+                ? findVariable(context.getScope(), emitParam)
+                : null
+            if (!variable) {
+              return
+            }
+            for (const reference of variable.references) {
+              emitReferenceIds.add(reference.identifier)
+            }
+          } else if (contextParam.type === 'Identifier') {
+            // `setup(props, context)`
+            const variable = findVariable(context.getScope(), contextParam)
+            for (const reference of variable.references) {
+              contextReferenceIds.add(reference.identifier)
+            }
+          }
+
+          setupContexts.set(vueNode, {
+            contextReferenceIds,
+            emitReferenceIds
+          })
+        }
+      }),
+      utils.defineScriptSetupVisitor(context, {
+        onDefineEmitsEnter(node, emits) {
+          for (const emit of emits) {
+            if (emit.emitName) {
+              emitDeclarations.set(emit.emitName, emit)
+            }
+          }
+
+          if (
+            !node.parent ||
+            node.parent.type !== 'VariableDeclarator' ||
+            node.parent.init !== node
+          ) {
+            return
+          }
+
+          const emitParam = node.parent.id
+          const variable =
+            emitParam.type === 'Identifier'
+              ? findVariable(context.getScope(), emitParam)
+              : null
+          if (!variable) {
+            return
+          }
+          /** @type {Set<Identifier>} */
+          const emitReferenceIds = new Set()
+          for (const reference of variable.references) {
+            emitReferenceIds.add(reference.identifier)
+          }
+          setupContexts.set(programNode, {
+            contextReferenceIds: new Set(),
+            emitReferenceIds
+          })
+        },
+        ...callVisitor
+      }),
+      {
+        'Program:exit'() {
+          for (const [name, emit] of emitDeclarations) {
+            if (!emitCalls.has(name) && emit.node) {
+              context.report({
+                node: emit.node,
+                loc: emit.node.loc,
+                messageId: 'unused',
+                data: { name }
+              })
+            }
+          }
+        }
+      }
+    )
+  }
+}
diff --git a/tests/lib/rules/no-unused-emit-declarations.js b/tests/lib/rules/no-unused-emit-declarations.js
new file mode 100644
index 000000000..0667ad464
--- /dev/null
+++ b/tests/lib/rules/no-unused-emit-declarations.js
@@ -0,0 +1,693 @@
+/**
+ * @author ItMaga
+ * See LICENSE file in root directory for full license.
+ */
+'use strict'
+
+const RuleTester = require('eslint').RuleTester
+const rule = require('../../../lib/rules/no-unused-emit-declarations')
+const {
+  getTypeScriptFixtureTestOptions
+} = require('../../test-utils/typescript')
+
+const tester = new RuleTester({
+  parser: require.resolve('vue-eslint-parser'),
+  parserOptions: {
+    ecmaVersion: 2020,
+    sourceType: 'module'
+  }
+})
+
+tester.run('no-unused-emit-declarations', rule, {
+  valid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['count', 'foo'],
+          methods: {
+              setCount () {
+                  this.$emit('count', newCount)
+              },
+              setFoo () {
+                  this.$emit('foo', newFoo)
+              }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        emits: ['foo'],
+        methods: {
+          click () {
+            const vm = this
+            vm?.$emit?.('foo')
+          }
+        }
+      }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Bar</button>
+      </template>
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+          methods: {
+              setFoo () {
+                  this.$emit('foo', newFoo)
+              }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="this.$emit('bar')">Bar</button>
+      </template>
+      <script>
+        export default {
+          emits: ['bar'],
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Bar</button>
+      </template>
+      <script setup>
+        const emit = defineEmits(['foo', 'bar'])
+        const setFoo = () => {
+          emit('foo', newFoo)
+        }
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, { emit }) {
+            const setFoo = () => {
+              emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, { emit: customName }) {
+            const setFoo = () => customName('foo')
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: { foo: null },
+          setup(_, { emit }) {
+            const setFoo = () => {
+              emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          setup(_, { emit }) {
+            const setFoo = () => {
+              emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Bar</button>
+      </template>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, context) {
+            const setFoo = () => {
+              context.emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, { emit }) {
+            useCustomComposable(emit)
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, context) {
+            useCustomComposable(context.emit)
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, { emit }) {
+            useCustomComposable([emit])
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, context) {
+            useCustomComposable([context.emit])
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, context) {
+            useCustomComposable({ emit: context.emit }) 
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: [...foo],
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        const emits = ['foo'];
+        export default {
+          emits: [...emits],
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        const emits = ['foo'];
+        export default {
+          emits: emits,
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup(_, { emit }) {
+            useCustomComposable({ emit: emit }) 
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+          setup(_, { emit }) {
+            const emitBar = () => {
+              emit('bar', newBar)
+            }
+          },
+          methods: {
+            setFoo() {
+              this.$emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup>
+        defineEmits(...foo)
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup>
+        const emits = ['foo'];
+        defineEmits([...emits])
+      </script>
+      `
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      const emit = defineEmits<{
+        (e: 'foo'): void
+      }>()
+      const change = () => emit('foo');
+      `,
+      parserOptions: { parser: require.resolve('@typescript-eslint/parser') }
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      const emit = defineEmits<{
+        foo: [string, number]
+      }>()
+      const change = () => emit('foo');
+      `,
+      ...getTypeScriptFixtureTestOptions()
+    }
+  ],
+  invalid: [
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'count'],
+          methods: {
+            setFoo () {
+              this.$emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 26,
+          endColumn: 33
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+      export default {
+        emits: ['foo', 'bar'],
+        methods: {
+          click () {
+            const vm = this
+            vm?.$emit?.('foo')
+          }
+        }
+      }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 24,
+          endColumn: 29
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Foo</button>
+      </template>
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 7,
+          column: 19,
+          endColumn: 24
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: { foo: null },
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 20,
+          endColumn: 29
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Bar</button>
+      </template>
+      <script setup>
+        const emit = defineEmits(['foo', 'bar'])
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 6,
+          column: 35,
+          endColumn: 40
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          methods: {
+              setFoo () {
+                  custom.$emit('foo', newFoo)
+              }
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 19,
+          endColumn: 24
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+          setup(_, { emit }) {
+            const setFoo = () => {
+              emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 26,
+          endColumn: 31
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <template>
+        <button @click="$emit('bar')">Bar</button>
+      </template>
+      <script>
+        // @vue/component
+        const Foo = {
+          emits: ['foo', 'bar'],
+        }
+        export default Foo
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 8,
+          column: 19,
+          endColumn: 24
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+          setup(_, { emit: customName }) {
+            const setFoo = () => customName('foo')
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 26,
+          endColumn: 31
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo'],
+          setup() {
+            const setFoo = () => foo.$emit('foo')
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 19,
+          endColumn: 24
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'bar'],
+          setup(_, context) {
+            const setFoo = () => {
+              context.emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 26,
+          endColumn: 31
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script>
+        export default {
+          emits: ['foo', 'bar', 'baz'],
+          setup(_, { emit }) {
+            const emitBar = () => {
+              emit('bar', newBar)
+            }
+          },
+          methods: {
+            setFoo() {
+              this.$emit('foo', newFoo)
+            }
+          }
+        }
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          endLine: 4,
+          column: 33,
+          endColumn: 38
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+        const emit = defineEmits<{
+          (e: 'foo' | 'bar'): void;
+        }>()
+        const change = () => emit('foo');
+      `,
+      parserOptions: { parser: require.resolve('@typescript-eslint/parser') },
+      errors: [
+        {
+          messageId: 'unused',
+          line: 4,
+          column: 11,
+          endColumn: 36
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup>
+        const emits = ['foo'];
+        defineEmits(emits)
+      </script>
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 3,
+          column: 24,
+          endColumn: 29
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+        defineEmits<{(e: 'foo'): void}>()
+      </script>
+      `,
+      parserOptions: { parser: require.resolve('@typescript-eslint/parser') },
+      errors: [
+        {
+          messageId: 'unused',
+          line: 3,
+          column: 22,
+          endColumn: 38
+        }
+      ]
+    },
+    {
+      filename: 'test.vue',
+      code: `
+      <script setup lang="ts">
+      const emit = defineEmits<{
+        foo: [string, number],
+        bar: []
+      }>()
+      const change = () => emit('foo');
+      `,
+      errors: [
+        {
+          messageId: 'unused',
+          line: 5,
+          column: 9,
+          endColumn: 16
+        }
+      ],
+      ...getTypeScriptFixtureTestOptions()
+    }
+  ]
+})

From cd70b08414d78cdd7044269e2c73a8e38f566c20 Mon Sep 17 00:00:00 2001
From: ItMaga <m-chemurziev@ya.ru>
Date: Mon, 13 Nov 2023 16:38:35 +0300
Subject: [PATCH 2/3] join conditions

---
 lib/rules/no-unused-emit-declarations.js | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/lib/rules/no-unused-emit-declarations.js b/lib/rules/no-unused-emit-declarations.js
index 71ac91a64..8f1031163 100644
--- a/lib/rules/no-unused-emit-declarations.js
+++ b/lib/rules/no-unused-emit-declarations.js
@@ -228,16 +228,12 @@ module.exports = {
         },
         onSetupFunctionEnter(node, { node: vueNode }) {
           const contextParam = node.params[1]
-          if (!contextParam) {
-            // no arguments
-            return
-          }
-          if (contextParam.type === 'RestElement') {
-            // cannot check
-            return
-          }
-          if (contextParam.type === 'ArrayPattern') {
-            // cannot check
+          if (
+            !contextParam ||
+            contextParam.type === 'RestElement' ||
+            contextParam.type === 'ArrayPattern'
+          ) {
+            // no arguments or cannot check
             return
           }
 

From af1ec9ba20e459d6d2d2e8af8da33d6e1414b4b9 Mon Sep 17 00:00:00 2001
From: Flo Edelmann <git@flo-edelmann.de>
Date: Tue, 14 Nov 2023 18:57:45 +0100
Subject: [PATCH 3/3] Fix JSDoc types

---
 lib/rules/no-unused-emit-declarations.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/rules/no-unused-emit-declarations.js b/lib/rules/no-unused-emit-declarations.js
index 8f1031163..1414b50c4 100644
--- a/lib/rules/no-unused-emit-declarations.js
+++ b/lib/rules/no-unused-emit-declarations.js
@@ -28,7 +28,7 @@ const utils = require('../utils')
 /**
  * Get the name param node from the given CallExpression
  * @param {CallExpression} node CallExpression
- * @returns { NameWithLoc | null }
+ * @returns {NameWithLoc | null}
  */
 function getNameParamNode(node) {
   const nameLiteralNode = node.arguments[0]
@@ -118,7 +118,7 @@ module.exports = {
      *
      * @param {Array<Expression | SpreadElement>} args
      * @param {SetupContext} setupContext
-     * @returns
+     * @returns {boolean}
      */
     function verifyArgumentsReferences(args, setupContext) {
       for (const argument of args) {