diff --git a/Library/Homebrew/cmd/install.rb b/Library/Homebrew/cmd/install.rb
index e1e4712ea1..bacdb18f02 100644
--- a/Library/Homebrew/cmd/install.rb
+++ b/Library/Homebrew/cmd/install.rb
@@ -344,7 +344,7 @@ module Homebrew
   rescue FormulaInstallationAlreadyAttemptedError
     # We already attempted to install f as part of the dependency tree of
     # another formula. In that case, don't generate an error, just move on.
-    return
+    nil
   rescue CannotInstallFormulaError => e
     ofail e.message
   end
diff --git a/Library/Homebrew/cmd/reinstall.rb b/Library/Homebrew/cmd/reinstall.rb
index 7c62d8092a..420c08dfe8 100644
--- a/Library/Homebrew/cmd/reinstall.rb
+++ b/Library/Homebrew/cmd/reinstall.rb
@@ -47,7 +47,7 @@ module Homebrew
     fi.install
     fi.finish
   rescue FormulaInstallationAlreadyAttemptedError
-    return
+    nil
   rescue Exception # rubocop:disable Lint/RescueException
     ignore_interrupts { restore_backup(keg, keg_was_linked) }
     raise
diff --git a/Library/Homebrew/cmd/upgrade.rb b/Library/Homebrew/cmd/upgrade.rb
index 1446025805..4e6dd04631 100644
--- a/Library/Homebrew/cmd/upgrade.rb
+++ b/Library/Homebrew/cmd/upgrade.rb
@@ -139,7 +139,7 @@ module Homebrew
   rescue FormulaInstallationAlreadyAttemptedError
     # We already attempted to upgrade f as part of the dependency tree of
     # another formula. In that case, don't generate an error, just move on.
-    return
+    nil
   rescue CannotInstallFormulaError => e
     ofail e
   rescue BuildError => e
diff --git a/Library/Homebrew/diagnostic.rb b/Library/Homebrew/diagnostic.rb
index 79f5b2f1d0..1b779f226b 100644
--- a/Library/Homebrew/diagnostic.rb
+++ b/Library/Homebrew/diagnostic.rb
@@ -966,7 +966,7 @@ module Homebrew
           Putting non-prefixed coreutils in your path can cause gmp builds to fail.
         EOS
       rescue FormulaUnavailableError
-        return
+        nil
       end
 
       def check_for_non_prefixed_findutils
@@ -981,7 +981,7 @@ module Homebrew
           Putting non-prefixed findutils in your path can cause python builds to fail.
         EOS
       rescue FormulaUnavailableError
-        return
+        nil
       end
 
       def check_for_pydistutils_cfg_in_home
diff --git a/Library/Homebrew/extend/os/linux/system_config.rb b/Library/Homebrew/extend/os/linux/system_config.rb
index cf01765623..47eca7697e 100644
--- a/Library/Homebrew/extend/os/linux/system_config.rb
+++ b/Library/Homebrew/extend/os/linux/system_config.rb
@@ -31,7 +31,7 @@ class SystemConfig
       return "N/A" unless CoreTap.instance.installed?
       Formulary.factory(formula).linked_version || "N/A"
     rescue FormulaUnavailableError
-      return "N/A"
+      "N/A"
     end
 
     def dump_verbose_config(out = $stdout)
diff --git a/Library/Homebrew/formula_versions.rb b/Library/Homebrew/formula_versions.rb
index c10c69e674..67edba9c5e 100644
--- a/Library/Homebrew/formula_versions.rb
+++ b/Library/Homebrew/formula_versions.rb
@@ -44,7 +44,7 @@ class FormulaVersions
     # continue walking the history
     ohai "#{e} in #{name} at revision #{rev}", e.backtrace if ARGV.debug?
   rescue FormulaUnavailableError
-    return
+    nil
   ensure
     Homebrew.raise_deprecation_exceptions = false
   end
diff --git a/Library/Homebrew/tab.rb b/Library/Homebrew/tab.rb
index aa0208d51a..0fed724a8d 100644
--- a/Library/Homebrew/tab.rb
+++ b/Library/Homebrew/tab.rb
@@ -326,8 +326,8 @@ class Tab < OpenStruct
       "time" => time,
       "source_modified_time" => source_modified_time.to_i,
       "HEAD" => self.HEAD,
-      "stdlib" => (stdlib.to_s if stdlib),
-      "compiler" => (compiler.to_s if compiler),
+      "stdlib" => (stdlib&.to_s),
+      "compiler" => (compiler&.to_s),
       "aliases" => aliases,
       "runtime_dependencies" => runtime_dependencies,
       "source" => source,
diff --git a/Library/Homebrew/test/support/lib/config.rb b/Library/Homebrew/test/support/lib/config.rb
index e54fc111fa..a59d80c995 100644
--- a/Library/Homebrew/test/support/lib/config.rb
+++ b/Library/Homebrew/test/support/lib/config.rb
@@ -16,9 +16,9 @@ TEST_TMPDIR = ENV.fetch("HOMEBREW_TEST_TMPDIR") do |k|
 end
 
 # Paths pointing into the Homebrew code base that persist across test runs
-HOMEBREW_LIBRARY_PATH  = Pathname.new(File.expand_path("../../../..", __FILE__))
+HOMEBREW_LIBRARY_PATH  = Pathname.new(File.expand_path("../../..", __dir__))
 HOMEBREW_SHIMS_PATH    = HOMEBREW_LIBRARY_PATH.parent+"Homebrew/shims"
-HOMEBREW_LOAD_PATH     = [File.expand_path("..", __FILE__), HOMEBREW_LIBRARY_PATH].join(":")
+HOMEBREW_LOAD_PATH     = [File.expand_path(__dir__), HOMEBREW_LIBRARY_PATH].join(":")
 
 # Paths redirected to a temporary directory and wiped at the end of the test run
 HOMEBREW_PREFIX        = Pathname.new(TEST_TMPDIR).join("prefix")