diff --git a/Library/Homebrew/rubocops/lines_cop.rb b/Library/Homebrew/rubocops/lines_cop.rb
index cf1ac68c30..4d2d63cce2 100644
--- a/Library/Homebrew/rubocops/lines_cop.rb
+++ b/Library/Homebrew/rubocops/lines_cop.rb
@@ -99,15 +99,15 @@ module RuboCop
             problem "\"#{m.source}\" should be \"#{match[0]}\""
           end
 
-          # # Avoid hard-coding compilers
-          # find_every_method_call_by_name(body_node, :system).each do |m|
-          #   param = parameters(m).first
-          #   if match = regex_match_group(param, %r{(/usr/bin/)?(gcc|llvm-gcc|clang)\s?})
-          #     problem "Use \"\#{ENV.cc}\" instead of hard-coding \"#{match[3]}\""
-          #   elsif match = regex_match_group(param, %r{(/usr/bin/)?((g|llvm-g|clang)\+\+)\s?})
-          #     problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{match[3]}\""
-          #   end
-          # end
+          # Avoid hard-coding compilers
+          find_every_method_call_by_name(body_node, :system).each do |m|
+            param = parameters(m).first
+            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?})
+              problem "Use \"\#{ENV.cxx}\" instead of hard-coding \"#{match[2]}\""
+            end
+          end
           #
           # find_instance_method_call(body_node, :ENV, :[]=) do |m|
           #   param = parameters(m)[1]
diff --git a/Library/Homebrew/test/rubocops/lines_cop_spec.rb b/Library/Homebrew/test/rubocops/lines_cop_spec.rb
index c0cd754b3c..7e901f0e21 100644
--- a/Library/Homebrew/test/rubocops/lines_cop_spec.rb
+++ b/Library/Homebrew/test/rubocops/lines_cop_spec.rb
@@ -859,6 +859,54 @@ describe RuboCop::Cop::FormulaAudit::Miscellaneous do
         expect_offense(expected, actual)
       end
     end
+
+    it "with hardcoded compiler 1 " do
+      source = <<-EOS.undent
+        class Foo < Formula
+          desc "foo"
+          url 'http://example.com/foo-1.0.tgz'
+          def test
+            system "/usr/bin/gcc", "foo"
+          end
+        end
+      EOS
+
+      expected_offenses = [{  message: "Use \"\#{ENV.cc}\" instead of hard-coding \"gcc\"",
+                              severity: :convention,
+                              line: 5,
+                              column: 12,
+                              source: source }]
+
+      inspect_source(cop, source)
+
+      expected_offenses.zip(cop.offenses).each do |expected, actual|
+        expect_offense(expected, actual)
+      end
+    end
+
+    it "with hardcoded compiler 2 " do
+      source = <<-EOS.undent
+        class Foo < Formula
+          desc "foo"
+          url 'http://example.com/foo-1.0.tgz'
+          def test
+            system "/usr/bin/g++", "-o", "foo", "foo.cc"
+          end
+        end
+      EOS
+
+      expected_offenses = [{  message: "Use \"\#{ENV.cxx}\" instead of hard-coding \"g++\"",
+                              severity: :convention,
+                              line: 5,
+                              column: 12,
+                              source: source }]
+
+      inspect_source(cop, source)
+
+      expected_offenses.zip(cop.offenses).each do |expected, actual|
+        expect_offense(expected, actual)
+      end
+    end
   end
   def expect_offense(expected, actual)
     expect(actual.message).to eq(expected[:message])