diff --git a/Library/Homebrew/extend/os/mac/keg.rb b/Library/Homebrew/extend/os/mac/keg.rb
index 8f3977018297d..5fb0fbe0e6167 100644
--- a/Library/Homebrew/extend/os/mac/keg.rb
+++ b/Library/Homebrew/extend/os/mac/keg.rb
@@ -3,6 +3,19 @@
 class Keg
   GENERIC_KEG_LINK_DIRECTORIES = (remove_const :KEG_LINK_DIRECTORIES).freeze
   KEG_LINK_DIRECTORIES = (GENERIC_KEG_LINK_DIRECTORIES + ["Frameworks"]).freeze
+  GENERIC_MUST_EXIST_SUBDIRECTORIES = (remove_const :MUST_EXIST_SUBDIRECTORIES).freeze
+  MUST_EXIST_SUBDIRECTORIES = (
+    GENERIC_MUST_EXIST_SUBDIRECTORIES +
+    [HOMEBREW_PREFIX/"Frameworks"]
+  ).sort.uniq.freeze
   GENERIC_MUST_EXIST_DIRECTORIES = (remove_const :MUST_EXIST_DIRECTORIES).freeze
-  MUST_EXIST_DIRECTORIES = (GENERIC_MUST_EXIST_DIRECTORIES + [HOMEBREW_PREFIX/"Frameworks"]).sort.uniq.freeze
+  MUST_EXIST_DIRECTORIES = (
+    GENERIC_MUST_EXIST_DIRECTORIES +
+    [HOMEBREW_PREFIX/"Frameworks"]
+  ).sort.uniq.freeze
+  GENERIC_MUST_BE_WRITABLE_DIRECTORIES = (remove_const :MUST_BE_WRITABLE_DIRECTORIES).freeze
+  MUST_BE_WRITABLE_DIRECTORIES = (
+    GENERIC_MUST_BE_WRITABLE_DIRECTORIES +
+    [HOMEBREW_PREFIX/"Frameworks"]
+  ).sort.uniq.freeze
 end