diff --git a/Library/Homebrew/development_tools.rb b/Library/Homebrew/development_tools.rb
index a0f0fd5c6d325..5a379a04f12de 100644
--- a/Library/Homebrew/development_tools.rb
+++ b/Library/Homebrew/development_tools.rb
@@ -16,7 +16,7 @@ def locate(tool)
       # Don't call tools (cc, make, strip, etc.) directly!
       # Give the name of the binary you look for as a string to this method
       # in order to get the full path back as a Pathname.
-      (@locate ||= T.let({}, T.nilable(T::Hash[T.untyped, T.untyped]))).fetch(tool) do |key|
+      (@locate ||= T.let({}, T.nilable(T::Hash[T.any(String, Symbol), T.untyped]))).fetch(tool) do |key|
         @locate[key] = if File.executable?((path = "/usr/bin/#{tool}"))
           Pathname.new path
         # Homebrew GCCs most frequently; much faster to check this before xcrun
@@ -63,8 +63,9 @@ def default_compiler
     sig { returns(Version) }
     def clang_version
       @clang_version ||= T.let(
-        if (path = locate("clang")) && (bv = `#{path} --version`[/(?:clang|LLVM) version (\d+\.\d(?:\.\d)?)/, 1])
-          Version.new(bv)
+        if (path = locate("clang")) &&
+           (build_version = `#{path} --version`[/(?:clang|LLVM) version (\d+\.\d(?:\.\d)?)/, 1])
+          Version.new(build_version)
         else
           Version::NULL
         end, T.nilable(Version)
@@ -93,8 +94,8 @@ def clang_build_version
     def llvm_clang_build_version
       @llvm_clang_build_version ||= T.let(begin
         path = Formulary.factory("llvm").opt_prefix/"bin/clang"
-        if path.executable? && (bv = `#{path} --version`[/clang version (\d+\.\d\.\d)/, 1])
-          Version.new(bv)
+        if path.executable? && (build_version = `#{path} --version`[/clang version (\d+\.\d\.\d)/, 1])
+          Version.new(build_version)
         else
           Version::NULL
         end
@@ -109,8 +110,9 @@ def gcc_version(cc)
       (@gcc_version ||= T.let({}, T.nilable(T::Hash[String, Version]))).fetch(cc) do
         path = HOMEBREW_PREFIX/"opt/#{CompilerSelector.preferred_gcc}/bin"/cc
         path = locate(cc) unless path.exist?
-        version = if path && (bv = `#{path} --version`[/gcc(?:(?:-\d+(?:\.\d)?)? \(.+\))? (\d+\.\d\.\d)/, 1])
-          Version.new(bv)
+        version = if path &&
+                     (build_version = `#{path} --version`[/gcc(?:(?:-\d+(?:\.\d)?)? \(.+\))? (\d+\.\d\.\d)/, 1])
+          Version.new(build_version)
         else
           Version::NULL
         end
diff --git a/Library/Homebrew/unpack_strategy.rb b/Library/Homebrew/unpack_strategy.rb
index 44f47999d4f0a..a56e76ca58378 100644
--- a/Library/Homebrew/unpack_strategy.rb
+++ b/Library/Homebrew/unpack_strategy.rb
@@ -7,6 +7,7 @@
 module UnpackStrategy
   extend T::Helpers
 
+  # FIXME: Enable cop again when https://github.com/sorbet/sorbet/issues/3532 is fixed.
   AnyStrategy = T.type_alias do # rubocop:disable Style/MutableConstant
     T.any(
       T.class_of(UnpackStrategy::Tar),
@@ -101,6 +102,8 @@ def self.from_type(type)
 
   sig { params(extension: String).returns(T.nilable(AnyStrategy)) }
   def self.from_extension(extension)
+    return unless strategies
+
     strategies&.sort_by { |s| s.extensions.map(&:length).max || 0 }
               &.reverse
               &.find { |s| s.extensions.any? { |ext| extension.end_with?(ext) } }
@@ -113,15 +116,15 @@ def self.from_magic(path)
 
   sig {
     params(path: Pathname, prioritize_extension: T::Boolean, type: T.nilable(Symbol), ref_type: T.nilable(String),
-           ref: T.nilable(String), merge_xattrs: T.nilable(T::Boolean)).returns(T.untyped)
+           ref: T.nilable(String), merge_xattrs: T::Boolean).returns(T.untyped)
   }
-  def self.detect(path, prioritize_extension: false, type: nil, ref_type: nil, ref: nil, merge_xattrs: nil)
+  def self.detect(path, prioritize_extension: false, type: nil, ref_type: nil, ref: nil, merge_xattrs: false)
     strategy = from_type(type) if type
 
     if prioritize_extension && path.extname.present?
       strategy ||= from_extension(path.extname)
-      strategy ||= strategies&.select { |s| s < Directory || s == Fossil }
-                             &.find { |s| s.can_extract?(path) }
+
+      strategy ||= strategies&.find { |s| (s < Directory || s == Fossil) && s.can_extract?(path) }
     else
       strategy ||= from_magic(path)
       strategy ||= from_extension(path.extname)
@@ -135,14 +138,14 @@ def self.detect(path, prioritize_extension: false, type: nil, ref_type: nil, ref
   sig { returns(Pathname) }
   attr_reader :path
 
-  sig { returns(T.nilable(T::Boolean)) }
+  sig { returns(T::Boolean) }
   attr_reader :merge_xattrs
 
   sig {
     params(path: T.any(String, Pathname), ref_type: T.nilable(String), ref: T.nilable(String),
-           merge_xattrs: T.nilable(T::Boolean)).void
+           merge_xattrs: T::Boolean).void
   }
-  def initialize(path, ref_type: nil, ref: nil, merge_xattrs: nil)
+  def initialize(path, ref_type: nil, ref: nil, merge_xattrs: false)
     @path = T.let(Pathname(path).expand_path, Pathname)
     @ref_type = ref_type
     @ref = ref