Rudimentary fix for jashkenas/coffee-script#3379.

lib/coffee-script/lexer.js

@@ -169,7 +169,7 @@
       var octalEsc, quote, string, trimmed;
       switch (quote = this.chunk.charAt(0)) {
         case "'":
-          string = SIMPLESTR.exec(this.chunk)[0];
+          string = (SIMPLESTR.exec(this.chunk) || [])[0];
           break;
         case '"':
           string = this.balancedString(this.chunk, '"');

src/lexer.coffee

@@ -187,7 +187,7 @@ exports.Lexer = class Lexer
   # are balanced within the string's contents, and within nested interpolations.
   stringToken: ->
     switch quote = @chunk.charAt 0
-      when "'" then [string] = SIMPLESTR.exec @chunk
+      when "'" then [string] = SIMPLESTR.exec(@chunk) || []
       when '"' then string = @balancedString @chunk, '"'
     return 0 unless string
     trimmed = @removeNewlines string[1...-1]