Merge pull request rubocop#12782 from Earlopain/fix-error-for-style-a…

…lias-spec

Fix an error for `Style/Alias` when calling `alias_method` with fewer than 2 arguments.

changelog/fix_an_error_for_style_alias.md

@@ -0,0 +1 @@
+* [#12782](https://github.com/rubocop/rubocop/pull/12782): Fix an error for `Style/Alias` with `EnforcedStyle: prefer_alias` when calling `alias_method` with fewer than 2 arguments. ([@earlopain][])

lib/rubocop/cop/style/alias.rb

@@ -41,6 +41,7 @@ class Alias < Base
         def on_send(node)
           return unless node.command?(:alias_method)
           return unless style == :prefer_alias && alias_keyword_possible?(node)
+          return unless node.arguments.count == 2
 
           msg = format(MSG_ALIAS_METHOD, current: lexical_scope_type(node))
           add_offense(node.loc.selector, message: msg) do |corrector|

spec/rubocop/cop/style/alias_spec.rb

@@ -56,6 +56,14 @@ def foo
         end
       RUBY
     end
+
+    it 'register an offense for alias_method when calling with no arguments' do
+      expect_no_offenses('alias_method')
+    end
+
+    it 'registers no offense for alias_method when calling with one argument' do
+      expect_no_offenses('alias_method :foo')
+    end
   end
 
   context 'when EnforcedStyle is prefer_alias' do
@@ -208,5 +216,13 @@ def foo
         end
       RUBY
     end
+
+    it 'registers no offense for alias_method when calling with no arguments' do
+      expect_no_offenses('alias_method')
+    end
+
+    it 'registers no offense for alias_method when calling with one argument' do
+      expect_no_offenses('alias_method :foo')
+    end
   end
 end