diff --git a/Library/Homebrew/cli/parser.rb b/Library/Homebrew/cli/parser.rb
index 568ab62d06..536a100a28 100644
--- a/Library/Homebrew/cli/parser.rb
+++ b/Library/Homebrew/cli/parser.rb
@@ -296,7 +296,9 @@ module Homebrew
         [remaining, non_options]
       end
 
-      sig { params(argv: T::Array[String], ignore_invalid_options: T::Boolean).returns(Args) }
+      # @return [Args] The actual return type is `Args`, but since `Args` uses `method_missing` to handle options, the
+      #   `sig` annotates this as returning `T.untyped` to avoid spurious type errors.
+      sig { params(argv: T::Array[String], ignore_invalid_options: T::Boolean).returns(T.untyped) }
       def parse(argv = ARGV.freeze, ignore_invalid_options: false)
         raise "Arguments were already parsed!" if @args_parsed
 
diff --git a/Library/Homebrew/cmd/--env.rb b/Library/Homebrew/cmd/--env.rb
index a442e6ad4b..f9814ccd94 100644
--- a/Library/Homebrew/cmd/--env.rb
+++ b/Library/Homebrew/cmd/--env.rb
@@ -1,4 +1,4 @@
-# typed: false
+# typed: strict
 # frozen_string_literal: true
 
 require "extend/ENV"
@@ -49,7 +49,7 @@ module Homebrew
     end
 
     if shell.nil?
-      BuildEnvironment.dump ENV
+      BuildEnvironment.dump ENV.to_h
     else
       BuildEnvironment.keys(ENV.to_h).each do |key|
         puts Utils::Shell.export_value(key, ENV.fetch(key), shell)
diff --git a/Library/Homebrew/extend/ENV.rbi b/Library/Homebrew/extend/ENV.rbi
index f1fa0b4dcf..0c7c926da8 100644
--- a/Library/Homebrew/extend/ENV.rbi
+++ b/Library/Homebrew/extend/ENV.rbi
@@ -36,6 +36,7 @@ end
 
 module EnvActivation
   include EnvMethods
+  include Superenv
 end
 
 class Sorbet
diff --git a/Library/Homebrew/postinstall.rb b/Library/Homebrew/postinstall.rb
index f546df2727..ee5f1e798c 100644
--- a/Library/Homebrew/postinstall.rb
+++ b/Library/Homebrew/postinstall.rb
@@ -19,7 +19,7 @@ begin
 
   trap("INT", old_trap)
 
-  formula = T.must(args.named.to_resolved_formulae.first)
+  formula = args.named.to_resolved_formulae.first
   formula.extend(Debrew::Formula) if args.debug?
   formula.run_post_install
 rescue Exception => e # rubocop:disable Lint/RescueException