From 71c4c729e90e308e0afd70af7db5e9d9ff238527 Mon Sep 17 00:00:00 2001
From: sudalqueen <38751423+sudalqueen@users.noreply.github.com>
Date: Fri, 14 Aug 2020 01:25:04 +0900
Subject: [PATCH] fix(eslint-plugin): [prefer-includes] don't auto fix when
 `test` method's argument type doesn't have an 'includes' method (#2391)

---
 .../src/rules/prefer-includes.ts              | 19 ++++++++++++++++++-
 .../tests/rules/prefer-includes.test.ts       |  6 ++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/packages/eslint-plugin/src/rules/prefer-includes.ts b/packages/eslint-plugin/src/rules/prefer-includes.ts
index 721c53850df..fb34951611b 100644
--- a/packages/eslint-plugin/src/rules/prefer-includes.ts
+++ b/packages/eslint-plugin/src/rules/prefer-includes.ts
@@ -4,7 +4,12 @@ import {
 } from '@typescript-eslint/experimental-utils';
 import { AST as RegExpAST, parseRegExpLiteral } from 'regexpp';
 import * as ts from 'typescript';
-import { createRule, getParserServices, getStaticValue } from '../util';
+import {
+  createRule,
+  getParserServices,
+  getStaticValue,
+  getConstrainedTypeAtLocation,
+} from '../util';
 
 export default createRule({
   name: 'prefer-includes',
@@ -191,6 +196,18 @@ export default createRule({
           return;
         }
 
+        //check the argument type of test methods
+        const argument = callNode.arguments[0];
+        const tsNode = services.esTreeNodeToTSNodeMap.get(argument);
+        const type = getConstrainedTypeAtLocation(types, tsNode);
+
+        const includesMethodDecl = type
+          .getProperty('includes')
+          ?.getDeclarations();
+        if (includesMethodDecl == null) {
+          return;
+        }
+
         context.report({
           node: callNode,
           messageId: 'preferStringIncludes',
diff --git a/packages/eslint-plugin/tests/rules/prefer-includes.test.ts b/packages/eslint-plugin/tests/rules/prefer-includes.test.ts
index 17a05d08c4c..c72488a4937 100644
--- a/packages/eslint-plugin/tests/rules/prefer-includes.test.ts
+++ b/packages/eslint-plugin/tests/rules/prefer-includes.test.ts
@@ -115,6 +115,12 @@ ruleTester.run('prefer-includes', rule, {
         something.test(a)
       }
     `,
+    `
+      const pattern = new RegExp("bar")
+      function f(a) {
+        return pattern.test(a)
+      }
+    `,
   ]),
   invalid: addOptional([
     // positive