diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 2737da80e7..c6e43af8b2 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -71,6 +71,9 @@ jobs:
         else
           # Link old gettext (otherwise `brew doctor` is sad)
           brew link gettext
+
+          # remove deleted formula
+          brew uninstall --force python@2
         fi
         brew doctor
 
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index cdf37ee2fe..ae7bb34fa9 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -3,6 +3,7 @@
 require "keg"
 require "language/python"
 require "formula"
+require "formulary"
 require "version"
 require "development_tools"
 require "utils/shell"
@@ -832,6 +833,23 @@ module Homebrew
         EOS
       end
 
+      def check_deleted_formula
+        kegs = Keg.all
+        deleted_formulae = []
+        kegs.each do |keg|
+          keg_name = keg.name
+          deleted_formulae << keg_name if Formulary.tap_paths(keg_name).blank?
+        end
+        return if deleted_formulae.blank?
+
+        message = <<~EOS
+          Some installed formulae were deleted!
+          You should find replacements for the following formulae:
+            #{deleted_formulae.join("\n  ")}
+        EOS
+        message
+      end
+
       def all
         methods.map(&:to_s).grep(/^check_/)
       end