diff --git a/lib/step.rb b/lib/step.rb
index 660066be..09955588 100644
--- a/lib/step.rb
+++ b/lib/step.rb
@@ -214,7 +214,7 @@ def run(dry_run: false, fail_fast: false)
       end
 
       os_string = if OS.mac?
-        str = +"macOS #{MacOS.version.pretty_name} (#{MacOS.version})"
+        str = "macOS #{MacOS.version.pretty_name} (#{MacOS.version})"
         str << " on Apple Silicon" if Hardware::CPU.arm?
 
         str
diff --git a/lib/tests/formulae_dependents.rb b/lib/tests/formulae_dependents.rb
index 1015ee3c..4880f583 100644
--- a/lib/tests/formulae_dependents.rb
+++ b/lib/tests/formulae_dependents.rb
@@ -345,7 +345,7 @@ def install_dependent(dependent, testable_dependents, args:, build_from_source:
            all_tests_passed &&
            dependent.deps.all? { |d| bottled?(d.to_formula, no_older_versions: true) }
           os_string = if OS.mac?
-            str = +"macOS #{MacOS.version.pretty_name} (#{MacOS.version})"
+            str = "macOS #{MacOS.version.pretty_name} (#{MacOS.version})"
             str << " on Apple Silicon" if Hardware::CPU.arm?
 
             str