diff --git a/lib/coffee-script/lexer.js b/lib/coffee-script/lexer.js
index 9d08d678..1d02d9cf 100644
--- a/lib/coffee-script/lexer.js
+++ b/lib/coffee-script/lexer.js
@@ -946,7 +946,7 @@
 
   HEREDOC_INDENT = /\n+([^\n\S]*)(?=\S)/g;
 
-  REGEX = /^\/(?!\/)((?:[^[\/\n\\]|\\[^\n]|\[(?:\\[^\n]|[^\]\n\\])*])*)(\/)?/;
+  REGEX = /^\/(?!\/)((?:[^\[\/\n\\]|\\[^\n]|\[(?:\\[^\n]|[^\]\n\\])*\])*)(\/)?/;
 
   REGEX_FLAGS = /^\w*/;
 
diff --git a/src/lexer.coffee b/src/lexer.coffee
index d4957137..2c46e649 100644
--- a/src/lexer.coffee
+++ b/src/lexer.coffee
@@ -837,11 +837,11 @@ HEREDOC_INDENT     = /\n+([^\n\S]*)(?=\S)/g
 # Regex-matching-regexes.
 REGEX = /// ^
   / (?!/) ((
-  ?: [^ [ / \n \\ ]  # every other thing
+  ?: [^ \[ / \n \\ ] # every other thing
    | \\[^\n]         # anything but newlines escaped
    | \[              # character class
        (?: \\[^\n] | [^ \] \n \\ ] )*
-     ]
+     \]
   )*) (/)?
 ///