diff --git a/Library/Homebrew/mktemp.rb b/Library/Homebrew/mktemp.rb
index c89d01c0ed..4bbf14b5dd 100644
--- a/Library/Homebrew/mktemp.rb
+++ b/Library/Homebrew/mktemp.rb
@@ -68,7 +68,7 @@ class Mktemp
     begin
       chown(nil, group_id, @tmpdir)
     rescue Errno::EPERM
-      opoo "Failed setting group \"#{T.unsafe(Etc.getgrgid(group_id)).name}\" on #{@tmpdir}"
+      opoo "Failed setting group \"#{T.must(Etc.getgrgid(group_id)).name}\" on #{@tmpdir}"
     end
 
     begin
diff --git a/Library/Homebrew/sorbet/rbi/upstream.rbi b/Library/Homebrew/sorbet/rbi/upstream.rbi
index bfb50d9bb1..877921e54f 100644
--- a/Library/Homebrew/sorbet/rbi/upstream.rbi
+++ b/Library/Homebrew/sorbet/rbi/upstream.rbi
@@ -3,7 +3,19 @@
 # This file contains temporary definitions for fixes that have
 # been submitted upstream to https://github.com/sorbet/sorbet.
 
-# https://github.com/sorbet/sorbet/pull/7647/files
+# https://github.com/sorbet/sorbet/pull/7650
+class Etc::Group < Struct
+  sig { returns(Integer) }
+  def gid; end
+  sig { returns(T::Array[String]) }
+  def mem; end
+  sig { returns(String) }
+  def name; end
+  sig { returns(String) }
+  def passwd; end
+end
+
+# https://github.com/sorbet/sorbet/pull/7647
 module IRB
   sig { params(ap_path: T.nilable(String), argv: T::Array[String]).void }
   def self.setup(ap_path, argv: ::ARGV); end