From f24cdf468977ce114c6460107823b747034b498c Mon Sep 17 00:00:00 2001
From: sudalqueen <abbey17@cnu.ac.kr>
Date: Tue, 4 Aug 2020 23:56:33 +0900
Subject: [PATCH 1/3] test: add test case to prefer-includes.test.ts

Add test cases for RegExp in prefer-includes.test.ts
---
 packages/eslint-plugin/tests/rules/prefer-includes.test.ts | 6 ++++++
 1 file changed, 6 insertions(+)

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

From 18d1c1e5ed2271d9190aaf43a6a4a5965f14cf3e Mon Sep 17 00:00:00 2001
From: sudalqueen <abbey17@cnu.ac.kr>
Date: Thu, 13 Aug 2020 23:02:28 +0900
Subject: [PATCH 2/3] fix: add logic to check the argument type of test method

---
 .../src/rules/prefer-includes.ts              | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/eslint-plugin/src/rules/prefer-includes.ts b/packages/eslint-plugin/src/rules/prefer-includes.ts
index 721c53850df..9cc86ddcdce 100644
--- a/packages/eslint-plugin/src/rules/prefer-includes.ts
+++ b/packages/eslint-plugin/src/rules/prefer-includes.ts
@@ -191,6 +191,25 @@ export default createRule({
           return;
         }
 
+        const argument = callNode.arguments[0];
+        const tsNode = services.esTreeNodeToTSNodeMap.get(argument);
+        const argumentDeclarations = types
+          .getSymbolAtLocation(tsNode)
+          ?.getDeclarations();
+        if (argumentDeclarations == null || argumentDeclarations.length === 0) {
+          return;
+        }
+
+        for (const argumentDecl of argumentDeclarations) {
+          const type = types.getTypeAtLocation(argumentDecl);
+          const includesMethodDecl = type
+            .getProperty('includes')
+            ?.getDeclarations();
+          if (includesMethodDecl == null || includesMethodDecl == undefined) {
+            return;
+          }
+        }
+
         context.report({
           node: callNode,
           messageId: 'preferStringIncludes',

From d7891a3beeabda814d60513cfc90566a390db971 Mon Sep 17 00:00:00 2001
From: sudalqueen <abbey17@cnu.ac.kr>
Date: Thu, 13 Aug 2020 23:50:12 +0900
Subject: [PATCH 3/3] fix: edit type checking logic

use `getConstrainedTypeAtLocation` method for check argument type of `test` method.
---
 .../src/rules/prefer-includes.ts              | 26 +++++++++----------
 1 file changed, 12 insertions(+), 14 deletions(-)

diff --git a/packages/eslint-plugin/src/rules/prefer-includes.ts b/packages/eslint-plugin/src/rules/prefer-includes.ts
index 9cc86ddcdce..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',
@@ -191,25 +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 argumentDeclarations = types
-          .getSymbolAtLocation(tsNode)
+        const type = getConstrainedTypeAtLocation(types, tsNode);
+
+        const includesMethodDecl = type
+          .getProperty('includes')
           ?.getDeclarations();
-        if (argumentDeclarations == null || argumentDeclarations.length === 0) {
+        if (includesMethodDecl == null) {
           return;
         }
 
-        for (const argumentDecl of argumentDeclarations) {
-          const type = types.getTypeAtLocation(argumentDecl);
-          const includesMethodDecl = type
-            .getProperty('includes')
-            ?.getDeclarations();
-          if (includesMethodDecl == null || includesMethodDecl == undefined) {
-            return;
-          }
-        }
-
         context.report({
           node: callNode,
           messageId: 'preferStringIncludes',