Fix an infinite loop error for Layout/ArrayAlignment

Fixes standardrb/standard#517.

This PR fixes an infinite loop error for `Layout/ArrayAlignment`
when using assigning unbracketed array elements.

changelog/fix_infinite_loop_error_for_layout_array_alignment.md

@@ -0,0 +1 @@
+* [#11537](https://github.com/rubocop/rubocop/pull/11537): Fix an infinite loop error for `Layout/ArrayAlignment` when using assigning unbracketed array elements. ([@koic][])

lib/rubocop/cop/layout/array_alignment.rb

@@ -76,7 +76,7 @@ def base_column(node, args)
         end
 
         def target_method_lineno(node)
-          node.loc.line
+          node.bracketed? ? node.loc.line : node.parent.loc.line
         end
       end
     end

spec/rubocop/cop/layout/array_alignment_spec.rb

@@ -202,6 +202,39 @@
       RUBY
     end
 
+    it 'accepts when assigning aligned bracketed array elements' do
+      expect_no_offenses(<<~RUBY)
+        var = [
+          first,
+          second
+        ]
+      RUBY
+    end
+
+    it 'accepts when assigning aligned unbracketed array elements' do
+      expect_no_offenses(<<~RUBY)
+        var =
+          first,
+          second
+      RUBY
+    end
+
+    it 'registers an offense when assigning not aligned unbracketed array elements' do
+      expect_offense(<<~RUBY)
+        var =
+             first,
+             ^^^^^ Use one level of indentation for elements following the first line of a multi-line array.
+            second
+            ^^^^^^ Use one level of indentation for elements following the first line of a multi-line array.
+      RUBY
+
+      expect_correction(<<~RUBY)
+        var =
+          first,
+          second
+      RUBY
+    end
+
     it 'accepts single line array' do
       expect_no_offenses('array = [ a, b ]')
     end