start_with.rb in rubocop-performance-1.5.1

- old
+ new

@@ -7,23 +7,27 @@
       # `String#start_with?` would suffice.
       #
       # @example
       #   # bad
       #   'abc'.match?(/\Aab/)
+      #   /\Aab/.match?('abc')
       #   'abc' =~ /\Aab/
+      #   /\Aab/ =~ 'abc'
       #   'abc'.match(/\Aab/)
+      #   /\Aab/.match('abc')
       #
       #   # good
       #   'abc'.start_with?('ab')
       class StartWith < Cop
         MSG = 'Use `String#start_with?` instead of a regex match anchored to ' \
               'the beginning of the string.'
         SINGLE_QUOTE = "'"
 
         def_node_matcher :redundant_regex?, <<-PATTERN
           {(send $!nil? {:match :=~ :match?} (regexp (str $#literal_at_start?) (regopt)))
-           (send (regexp (str $#literal_at_start?) (regopt)) {:match :=~} $_)}
+           (send (regexp (str $#literal_at_start?) (regopt)) {:match :match?} $_)
+           (match-with-lvasgn (regexp (str $#literal_at_start?) (regopt)) $_)}
         PATTERN
 
         def literal_at_start?(regex_str)
           # is this regexp 'literal' in the sense of only matching literal
           # chars, rather than using metachars like `.` and `*` and so on?
@@ -37,9 +41,10 @@
         def on_send(node)
           return unless redundant_regex?(node)
 
           add_offense(node)
         end
+        alias on_match_with_lvasgn on_send
 
         def autocorrect(node)
           redundant_regex?(node) do |receiver, regex_str|
             receiver, regex_str = regex_str, receiver if receiver.is_a?(String)
             regex_str = regex_str[2..-1] # drop \A anchor