diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 5d6e2de74f..a86867c2af 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -1107,7 +1107,7 @@ class FormulaInstaller
   end
 
   def forbidden_license_check
-    forbidden_licenses = (Homebrew::EnvConfig.forbidden_licenses || "").split(" ")
+    forbidden_licenses = Homebrew::EnvConfig.forbidden_licenses.to_s.split(" ")
     return if forbidden_licenses.blank?
 
     if forbidden_licenses.include? formula.license