From bc1c5567555c1e38d931979484d01f566d171e76 Mon Sep 17 00:00:00 2001
From: Matthew Olsson <matthewcolsson@gmail.com>
Date: Sun, 7 Jun 2020 19:32:25 -0700
Subject: [PATCH] LibJS: Move regex logic to main Lexer if statement

This prevents a regex such as /=/ from lexing into TokenType::SlashEquals,
preventing the regex logic from working.
---
 Libraries/LibJS/Lexer.cpp | 45 ++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

diff --git a/Libraries/LibJS/Lexer.cpp b/Libraries/LibJS/Lexer.cpp
index 911dc6b808..2d3d36e42d 100644
--- a/Libraries/LibJS/Lexer.cpp
+++ b/Libraries/LibJS/Lexer.cpp
@@ -418,6 +418,29 @@ Token Lexer::next()
             consume();
             token_type = TokenType::StringLiteral;
         }
+    } else if (m_current_char == '/' && !slash_means_division()) {
+        consume();
+        token_type = TokenType::RegexLiteral;
+
+        while (!is_eof()) {
+            if (m_current_char == '[') {
+                m_regex_is_in_character_class = true;
+            } else if (m_current_char == ']') {
+                m_regex_is_in_character_class = false;
+            } else if (!m_regex_is_in_character_class && m_current_char == '/') {
+                break;
+            }
+
+            if (match('\\', '/') || match('\\', '[') || match('\\', '\\') || (m_regex_is_in_character_class && match('\\', ']')))
+                consume();
+            consume();
+        }
+
+        if (is_eof()) {
+            token_type = TokenType::UnterminatedRegexLiteral;
+        } else {
+            consume();
+        }
     } else if (m_current_char == EOF) {
         token_type = TokenType::Eof;
     } else {
@@ -473,28 +496,6 @@ Token Lexer::next()
         if (!found_four_char_token && !found_three_char_token && !found_two_char_token && !found_one_char_token) {
             consume();
             token_type = TokenType::Invalid;
-        } else if (token_type == TokenType::Slash && !slash_means_division()) {
-            token_type = TokenType::RegexLiteral;
-
-            while (!is_eof()) {
-                if (m_current_char == '[') {
-                    m_regex_is_in_character_class = true;
-                } else if (m_current_char == ']') {
-                    m_regex_is_in_character_class = false;
-                } else if (!m_regex_is_in_character_class && m_current_char == '/') {
-                    break;
-                }
-
-                if (match('\\', '/') || match('\\', '[') || match('\\', '\\') || (m_regex_is_in_character_class && match('\\', ']')))
-                    consume();
-                consume();
-            }
-
-            if (is_eof()) {
-                token_type = TokenType::UnterminatedRegexLiteral;
-            } else {
-                consume();
-            }
         }
     }