Fix an error for Style/ExactRegexpMatch when calling match withou…

…t a receiver

changelog/fix_an_error_for_style_exact_regexp_match.md

@@ -0,0 +1 @@
+* [#12781](https://github.com/rubocop/rubocop/pull/12781): Fix an error for `Style/ExactRegexpMatch` when calling `match` without a receiver. ([@earlopain][])

lib/rubocop/cop/style/exact_regexp_match.rb

@@ -38,12 +38,13 @@ class ExactRegexpMatch < Base
         PATTERN
 
         def on_send(node)
+          return unless (receiver = node.receiver)
           return unless (regexp = exact_regexp_match(node))
 
           parsed_regexp = Regexp::Parser.parse(regexp)
           return unless exact_match_pattern?(parsed_regexp)
 
-          prefer = "#{node.receiver.source} #{new_method(node)} '#{parsed_regexp[1].text}'"
+          prefer = "#{receiver.source} #{new_method(node)} '#{parsed_regexp[1].text}'"
 
           add_offense(node, message: format(MSG, prefer: prefer)) do |corrector|
             corrector.replace(node, prefer)

spec/rubocop/cop/style/exact_regexp_match_spec.rb

@@ -45,6 +45,10 @@
     RUBY
   end
 
+  it 'does not register an offense when using match without receiver' do
+    expect_no_offenses('match(/\\Astring\\z/)')
+  end
+
   it 'registers an offense when using `string.match?(/\Astring\z/)`' do
     expect_offense(<<~'RUBY')
       string.match?(/\Astring\z/)