diff --git a/Library/Homebrew/dev-cmd/irb.rb b/Library/Homebrew/dev-cmd/irb.rb
index b5b09f9b1c3515512945ffd3276c6f45332e765b..2ba4d7781fa58d7f6cc40262a90ea3796722b019 100644
--- a/Library/Homebrew/dev-cmd/irb.rb
+++ b/Library/Homebrew/dev-cmd/irb.rb
@@ -1,6 +1,7 @@
 # typed: false
 # frozen_string_literal: true
 
+require "formulary"
 require "cli/parser"
 
 class Symbol