Fix issues reported by fasterer

.fasterer.yml

@@ -1,4 +1,3 @@
 exclude_paths:
-  - lib/diff/lcs.rb # sort_vs_sort_by on priority_compare
-  - Rakefile # each_with_index vs while
-  - spec/spec_helper.rb
+  - research/**/*
+  - pkg/**/*

Gemfile

@@ -11,10 +11,14 @@ if RUBY_VERSION < '1.9'
   gem 'rdoc', '< 4'
 
   gem 'ruby-debug'
-elsif RUBY_VERSION >= '2.0'
+end
+
+if RUBY_VERSION >= '2.0'
+  gem 'standardrb'
+  gem 'fasterer'
+
   if RUBY_ENGINE == 'ruby'
     gem 'simplecov', '~> 0.18'
-
     gem 'byebug'
   end
 end

lib/diff/lcs.rb

@@ -145,7 +145,7 @@ def lcs(seq1, seq2, &block) #:yields seq1[i] for each matched:
     matches = Diff::LCS::Internals.lcs(seq1, seq2)
     ret = []
     string = seq1.kind_of? String
-    matches.each_with_index do |_e, i|
+    matches.each_index do |i|
       next if matches[i].nil?
 
       v = string ? seq1[i, 1] : seq1[i]

lib/diff/lcs/hunk.rb

@@ -22,7 +22,7 @@ def initialize(data_old, data_new, piece, flag_context, file_length_difference)
     end
 
     if String.method_defined?(:encoding)
-      @preferred_data_encoding = data_old.fetch(0, data_new.fetch(0, '')).encoding
+      @preferred_data_encoding = data_old.fetch(0) { data_new.fetch(0) { '' } }.encoding
     end
 
     @data_old = data_old

spec/spec_helper.rb

@@ -355,9 +355,7 @@ module Matchers
 
     matcher :correctly_map_sequence do |s1|
       match do |actual|
-        actual.each_with_index { |ee, ii|
-          expect(ee).to be_nil_or_match_values(ii, s1, @s2)
-        }
+        actual.each_index { |ii| expect(actual[ii]).to be_nil_or_match_values(ii, s1, @s2) }
       end
 
       chain :to_other_sequence do |s2|