From 2afa8497c096ba85489b4f242c64a0cdf1b06214 Mon Sep 17 00:00:00 2001
From: Bo Anderson <mail@boanderson.me>
Date: Thu, 9 Jul 2020 10:40:00 +0100
Subject: [PATCH] formula: consider aliases in installed_prefixes

---
 Library/Homebrew/formula.rb | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/Library/Homebrew/formula.rb b/Library/Homebrew/formula.rb
index 97027612ea..f408bff786 100644
--- a/Library/Homebrew/formula.rb
+++ b/Library/Homebrew/formula.rb
@@ -598,7 +598,16 @@ class Formula
   # All currently installed prefix directories.
   # @private
   def installed_prefixes
-    rack.directory? ? rack.subdirs.sort : []
+    prefixes = rack.directory? ? rack.subdirs : []
+
+    prefixes += (aliases + Array(oldname)).flat_map do |alias_name|
+      rack_alias = HOMEBREW_CELLAR/alias_name
+      next unless rack_alias.directory?
+
+      rack_alias.subdirs
+    end.compact
+
+    prefixes.sort_by(&:basename)
   end
 
   # All currently installed kegs.