[Fix rubocop#257] Fix an incorrect auto-correct for `Performance/MapC…

…ompact`

Fixes rubocop#257.

This PR fixes an incorrect auto-correct for `Performance/MapCompact` when
using multi-line `collection.map { ... }.compact` as a method argument.

CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## master (unreleased)
 
+### Bug fixes
+
+* [#257](https://github.com/rubocop/rubocop-performance/issues/257): Fix an incorrect auto-correct for `Performance/MapCompact` when using multi-line `collection.map { ... }.compact` as a method argument. ([@koic][])
+
 ## 1.11.4 (2021-07-07)
 
 ### Bug fixes

lib/rubocop/cop/performance/map_compact.rb

@@ -66,7 +66,7 @@ def remove_compact_method(corrector, compact_node)
           chained_method = compact_node.parent
           compact_method_range = compact_node.loc.selector
 
-          if compact_node.multiline? && chained_method&.loc.respond_to?(:selector) &&
+          if compact_node.multiline? && chained_method&.loc.respond_to?(:selector) && chained_method.dot? &&
              !invoke_method_after_map_compact_on_same_line?(compact_node, chained_method)
             compact_method_range = range_by_whole_lines(compact_method_range, include_final_newline: true)
           else

spec/rubocop/cop/performance/map_compact_spec.rb

@@ -128,6 +128,23 @@
       RUBY
     end
 
+    it 'registers an offense when using multi-line `collection.map { ... }.compact` as a method argument' do
+      expect_offense(<<~RUBY)
+        do_something(
+          collection.map { |item|
+                     ^^^^^^^^^^^^ Use `filter_map` instead.
+          }.compact
+        )
+      RUBY
+
+      expect_correction(<<~RUBY)
+        do_something(
+          collection.filter_map { |item|
+          }
+        )
+      RUBY
+    end
+
     it 'registers an offense when using multiline `map { ... }.compact` and assigning to return value' do
       expect_offense(<<~RUBY)
         ret = collection.map do |item|