improve linting settings

.eslintrc.js

@@ -379,6 +379,8 @@ const base = {
   'unicorn/no-hex-escape': 'error',
   // disallow if as the only statement in an else block
   'unicorn/no-lonely-if': 'error',
+  // forbid classes that only have static members
+  'unicorn/no-static-only-class': 'error',
   // disallow unreadable array destructuring
   'unicorn/no-unreadable-array-destructuring': 'error',
   // disallow unsafe regular expressions
@@ -457,12 +459,18 @@ const base = {
   'regexp/no-escape-backspace': 'error',
   // disallow invisible raw character
   'regexp/no-invisible-character': 'error',
+  // disallow legacy RegExp features
+  'regexp/no-legacy-features': 'error',
   // disallow octal escape sequence
   'regexp/no-octal': 'error',
+  // disallow unused capturing group
+  'regexp/no-unused-capturing-group': 'error',
   // disallow useless backreferences in regular expressions
   'regexp/no-useless-backreference': 'error',
   // disallow character class with one character
   'regexp/no-useless-character-class': 'error',
+  // disallow useless `$` replacements in replacement string
+  'regexp/no-useless-dollar-replacements': 'error',
   // disallow unnecessary string escaping
   'regexp/no-useless-escape': 'error',
   // disallow unnecessary exactly quantifier
@@ -479,8 +487,10 @@ const base = {
   'regexp/order-in-character-class': 'error',
   // enforce using character class
   'regexp/prefer-character-class': 'error',
-  // enforce using '\d'
+  // enforce using `\d`
   'regexp/prefer-d': 'error',
+  // enforces escape of replacement `$` character (`$$`)
+  'regexp/prefer-escape-replacement-dollar-char': 'error',
   // enforce using `+` quantifier
   'regexp/prefer-plus-quantifier': 'error',
   // enforce using quantifier

package.json

@@ -40,8 +40,8 @@
     "eslint-plugin-optimize-regex": "^1.2.0",
     "eslint-plugin-qunit": "^6.0.0",
     "eslint-plugin-radar": "~0.2.1",
-    "eslint-plugin-regexp": "~0.5.0",
-    "eslint-plugin-unicorn": "^28.0.2",
+    "eslint-plugin-regexp": "~0.6.1",
+    "eslint-plugin-unicorn": "^29.0.0",
     "karma": "^6.2.0",
     "karma-chrome-launcher": "^3.1.0",
     "karma-phantomjs-launcher": "~1.0.4",

packages/core-js/internals/fix-regexp-well-known-symbol-logic.js

@@ -25,6 +25,7 @@ var REPLACE_SUPPORTS_NAMED_GROUPS = !fails(function () {
 // IE <= 11 replaces $0 with the whole match, as if it was $&
 // https://stackoverflow.com/questions/6024666/getting-ie-to-replace-a-regex-with-the-literal-string-0
 var REPLACE_KEEPS_$0 = (function () {
+  // eslint-disable-next-line regexp/prefer-escape-replacement-dollar-char -- required for testing
   return 'a'.replace(/./, '$0') === '$0';
 })();
 

tests/compat/tests.js

@@ -870,6 +870,7 @@ GLOBAL.tests = {
     return ''.replace(O) == 7
       && execCalled
       && ''.replace(re2, '$<a>') === '7'
+      // eslint-disable-next-line regexp/prefer-escape-replacement-dollar-char -- required for testing
       && 'a'.replace(/./, '$0') === '$0'
       && /./[Symbol.replace]('a', '$0') === '$0';
   },

tests/tests/es.string.replace.js

@@ -1,3 +1,4 @@
+/* eslint-disable regexp/no-unused-capturing-group -- required for testibg */
 import { GLOBAL, NATIVE, STRICT } from '../helpers/constants';
 import { patchRegExp$exec } from '../helpers/helpers';
 
@@ -124,7 +125,9 @@ const run = assert => {
   assert.strictEqual('aaaaaaaaaa,aaaaaaaaaaaaaaa'.replace(/^(a+)\1*,\1+$/, '$1'), 'aaaaa', 'S15.5.4.11_A5_T1');
 
   // https://github.com/zloirock/core-js/issues/471
+  // eslint-disable-next-line regexp/no-useless-dollar-replacements -- required for testing
   assert.strictEqual('{price} Retail'.replace(/{price}/g, '$25.00'), '$25.00 Retail');
+  // eslint-disable-next-line regexp/prefer-escape-replacement-dollar-char -- required for testing
   assert.strictEqual('a'.replace(/(.)/, '$0'), '$0');
 };
 
@@ -203,12 +206,15 @@ QUnit.test('RegExp#@@replace correctly handles substitutions', assert => {
     result.index = 1;
     return result;
   };
+  // eslint-disable-next-line regexp/no-useless-dollar-replacements -- false positive
   assert.strictEqual('1234'.replace(re, '$1'), '174');
+  // eslint-disable-next-line regexp/no-useless-dollar-replacements -- required for testing
   assert.strictEqual('1234'.replace(re, '$<!!!>'), '174');
   assert.strictEqual('1234'.replace(re, '$`'), '114');
   assert.strictEqual('1234'.replace(re, '$\''), '144');
   assert.strictEqual('1234'.replace(re, '$$'), '1$4');
   assert.strictEqual('1234'.replace(re, '$&'), '1234');
+  // eslint-disable-next-line regexp/prefer-escape-replacement-dollar-char -- required for testing
   assert.strictEqual('1234'.replace(re, '$x'), '1$x4');
 
   let args;