diff --git a/Library/Homebrew/rubocops/lines.rb b/Library/Homebrew/rubocops/lines.rb
index dc17ec2ef1..5ed08a2e03 100644
--- a/Library/Homebrew/rubocops/lines.rb
+++ b/Library/Homebrew/rubocops/lines.rb
@@ -240,18 +240,18 @@ module RuboCop
           # Avoid hard-coding compilers
           find_every_method_call_by_name(body_node, :system).each do |method|
             param = parameters(method).first
-            if match = regex_match_group(param, %r{^(/usr/bin/)?(gcc|llvm-gcc|clang)[\s"]?})
+            if match = regex_match_group(param, %r{^(/usr/bin/)?(gcc|llvm-gcc|clang)(\s|$)})
               problem "Use \"\#{ENV.cc}\" instead of hard-coding \"#{match[2]}\""
-            elsif match = regex_match_group(param, %r{^(/usr/bin/)?((g|llvm-g|clang)\+\+)[\s"]?})
+            elsif match = regex_match_group(param, %r{^(/usr/bin/)?((g|llvm-g|clang)\+\+)(\s|$)})
               problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{match[2]}\""
             end
           end
 
           find_instance_method_call(body_node, "ENV", :[]=) do |method|
             param = parameters(method)[1]
-            if match = regex_match_group(param, %r{^(/usr/bin/)?(gcc|llvm-gcc|clang)[\s"]?})
+            if match = regex_match_group(param, %r{^(/usr/bin/)?(gcc|llvm-gcc|clang)(\s|$)})
               problem "Use \"\#{ENV.cc}\" instead of hard-coding \"#{match[2]}\""
-            elsif match = regex_match_group(param, %r{^(/usr/bin/)?((g|llvm-g|clang)\+\+)[\s"]?})
+            elsif match = regex_match_group(param, %r{^(/usr/bin/)?((g|llvm-g|clang)\+\+)(\s|$)})
               problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{match[2]}\""
             end
           end