diff --git a/rspec-core/lib/rspec/core/metadata.rb b/rspec-core/lib/rspec/core/metadata.rb
index 094a7a3b3..c68627ac5 100644
--- a/rspec-core/lib/rspec/core/metadata.rb
+++ b/rspec-core/lib/rspec/core/metadata.rb
@@ -169,7 +169,7 @@ def file_path_and_line_number_from(backtrace)
         end
 
         def description_separator(parent_part, child_part)
-          if parent_part.is_a?(Module) && child_part =~ /^(#|::|\.)/
+          if parent_part.is_a?(Module) && /^(?:#|::|\.)/.match(child_part.to_s)
             ''.freeze
           else
             ' '.freeze