diff --git a/rules/regex-shorthand.js b/rules/regex-shorthand.js
index 63e3b2f426..39f4455b82 100644
--- a/rules/regex-shorthand.js
+++ b/rules/regex-shorthand.js
@@ -1,6 +1,6 @@
 'use strict';
 const cleanRegexp = require('clean-regexp');
-const {generate, optimize, parse} = require('regexp-tree');
+const {optimize} = require('regexp-tree');
 const getDocumentationUrl = require('./utils/get-documentation-url');
 const quoteString = require('./utils/quote-string');
 
@@ -9,32 +9,21 @@ const message = 'Use regex shorthands to improve readability.';
 const create = context => {
 	return {
 		'Literal[regex]': node => {
-			const {type, value} = context.getSourceCode().getFirstToken(node);
+			const {raw: original, regex} = node;
 
-			if (type !== 'RegularExpression') {
+			// Regular Expressions with `u` flag are not well handled by `regexp-tree`
+			// https://github.com/DmitrySoshnikov/regexp-tree/issues/162
+			if (regex.flags.includes('u')) {
 				return;
 			}
 
-			let parsedSource;
-			try {
-				parsedSource = parse(value);
-			} catch (error) {
-				context.report({
-					node,
-					message: '{{original}} can\'t be parsed: {{message}}',
-					data: {
-						original: value,
-						message: error.message
-					}
-				});
+			let optimized = original;
 
-				return;
-			}
-
-			const originalRegex = generate(parsedSource).toString();
-			const optimizedRegex = optimize(value).toString();
+			try {
+				optimized = optimize(original).toString();
+			} catch (_) {}
 
-			if (originalRegex === optimizedRegex) {
+			if (original === optimized) {
 				return;
 			}
 
@@ -42,12 +31,10 @@ const create = context => {
 				node,
 				message: '{{original}} can be optimized to {{optimized}}',
 				data: {
-					original: value,
-					optimized: optimizedRegex
+					original,
+					optimized
 				},
-				fix(fixer) {
-					return fixer.replaceText(node, optimizedRegex);
-				}
+				fix: fixer => fixer.replaceText(node, optimized)
 			});
 		},
 		'NewExpression[callee.name="RegExp"]': node => {
diff --git a/test/regex-shorthand.js b/test/regex-shorthand.js
index d1a6fd6f20..dcceeab680 100644
--- a/test/regex-shorthand.js
+++ b/test/regex-shorthand.js
@@ -3,11 +3,8 @@ import avaRuleTester from 'eslint-ava-rule-tester';
 import rule from '../rules/regex-shorthand';
 
 const ruleTester = avaRuleTester(test, {
-	env: {
-		es6: true
-	},
 	parserOptions: {
-		sourceType: 'module'
+		ecmaVersion: 2020
 	}
 });
 
@@ -20,20 +17,36 @@ ruleTester.run('regex-shorthand', rule, {
 	valid: [
 		'const foo = /\\d/',
 		'const foo = /\\W/i',
-		'const foo = /\\w/ig',
-		'const foo = /[a-z]/ig',
-		'const foo = /\\d*?/ig',
+		'const foo = /\\w/gi',
+		'const foo = /[a-z]/gi',
+		'const foo = /\\d*?/gi',
 		'const foo = new RegExp(\'\\d\')',
 		'const foo = new RegExp(\'\\d\', \'ig\')',
 		'const foo = new RegExp(\'\\d*?\')',
 		'const foo = new RegExp(\'[a-z]\', \'i\')',
 		'const foo = new RegExp(/\\d/)',
-		'const foo = new RegExp(/\\d/ig)',
+		'const foo = new RegExp(/\\d/gi)',
 		'const foo = new RegExp(/\\d/, \'ig\')',
 		'const foo = new RegExp(/\\d*?/)',
-		'const foo = new RegExp(/[a-z]/, \'i\')'
+		'const foo = new RegExp(/[a-z]/, \'i\')',
+
+		// Should not crash ESLint (#446 and #448)
+		'/\\{\\{verificationUrl\\}\\}/gu',
+		'/^test-(?<name>[a-zA-Z-\\d]+)$/u',
+
+		// Should not suggest wrong regex (#447)
+		'/(\\s|\\.|@|_|-)/u',
+		'/[\\s.@_-]/u'
 	],
 	invalid: [
+		{
+			code: 'const foo = /\\w/ig',
+			errors: [{
+				...error,
+				message: '/\\w/ig can be optimized to /\\w/gi'
+			}],
+			output: 'const foo = /\\w/gi'
+		},
 		{
 			code: 'const foo = /[0-9]/',
 			errors: [{