diff --git a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
index ff18605d42d11..fbd5b84252adc 100644
--- a/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
+++ b/Library/Homebrew/extend/os/mac/formula_cellar_checks.rb
@@ -65,7 +65,7 @@ def check_python_framework_links(lib)
     EOS
   end
 
-  sig { returns(T.nilable(String)) }
+  sig { void }
   def check_linkage
     return unless formula.prefix.directory?