diff --git a/lib/rouge/lexers/ruby.rb b/lib/rouge/lexers/ruby.rb
index d89cdc40be..f3094f3c1f 100644
--- a/lib/rouge/lexers/ruby.rb
+++ b/lib/rouge/lexers/ruby.rb
@@ -90,7 +90,7 @@ def self.detect?(text)
       end
 
       state :regex_flags do
-        rule %r/[mixounse]+/, Str::Regex, :pop!
+        rule %r/[mixounse]*/, Str::Regex, :pop!
       end
 
       # double-quoted string and symbol
@@ -267,7 +267,7 @@ def self.detect?(text)
       end
 
       state :test_heredoc do
-        rule %r/[^#\\\n]+$/ do |m|
+        rule %r/[^#\\\n]*$/ do |m|
           tolerant, heredoc_name = @heredoc_queue.first
           check = tolerant ? m[0].strip : m[0].rstrip