From 2ac03343f0f9382fbe459c43c5feacedf1d8b50e Mon Sep 17 00:00:00 2001
From: QQ <me@quang.be>
Date: Fri, 3 Jun 2022 15:08:22 +1000
Subject: [PATCH] Fix `Performance/MapCompact` autocorrect causing invalid
 syntax

This commit fixes the issue when `Performance/MapCompact` auto-correction
fails to detect the argument block of an assignment method so it deletes
the block ending (i.e. `end` or `}`) when `map { ... }.compact` is
multiline.

Before

```ruby
object.new_collection = collection.map do |item|
end.compact

object.new_collection = collection.filter_map do |item|
```

After

```ruby
object.new_collection = collection.map do |item|
end.compact

object.new_collection = collection.filter_map do |item|
end
```
---
 CHANGELOG.md                                        |  1 +
 ...mapcompact_autocorrect_causing_invalid_syntax.md |  1 +
 lib/rubocop/cop/performance/map_compact.rb          |  2 +-
 spec/rubocop/cop/performance/map_compact_spec.rb    | 13 +++++++++++++
 4 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 changelog/fix_performance_mapcompact_autocorrect_causing_invalid_syntax.md

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 36551bceef..fd02b1908d 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -362,3 +362,4 @@
 [@mvz]: https://github.com/mvz
 [@leoarnold]: https://github.com/leoarnold
 [@ydah]: https://github.com/ydah
+[@QQism]: https://github.com/QQism
diff --git a/changelog/fix_performance_mapcompact_autocorrect_causing_invalid_syntax.md b/changelog/fix_performance_mapcompact_autocorrect_causing_invalid_syntax.md
new file mode 100644
index 0000000000..763b896833
--- /dev/null
+++ b/changelog/fix_performance_mapcompact_autocorrect_causing_invalid_syntax.md
@@ -0,0 +1 @@
+* [#291](https://github.com/rubocop/rubocop-performance/pull/291): Fix `Performance/MapCompact` autocorrect causing invalid syntax when using multiline `map { ... }.compact` as an argument for an assignment method. ([@QQism][])
diff --git a/lib/rubocop/cop/performance/map_compact.rb b/lib/rubocop/cop/performance/map_compact.rb
index 3ae66f4b28..b3a168d772 100644
--- a/lib/rubocop/cop/performance/map_compact.rb
+++ b/lib/rubocop/cop/performance/map_compact.rb
@@ -83,7 +83,7 @@ def map_method_and_compact_method_on_same_line?(map_node, compact_node)
         end
 
         def invoke_method_after_map_compact_on_same_line?(compact_node, chained_method)
-          compact_node.loc.selector.line == chained_method.loc.selector.line
+          compact_node.loc.selector.line == chained_method.loc.last_line
         end
 
         def compact_method_with_final_newline_range(compact_method_range)
diff --git a/spec/rubocop/cop/performance/map_compact_spec.rb b/spec/rubocop/cop/performance/map_compact_spec.rb
index 5326f83b90..28f8d699ba 100644
--- a/spec/rubocop/cop/performance/map_compact_spec.rb
+++ b/spec/rubocop/cop/performance/map_compact_spec.rb
@@ -248,6 +248,19 @@
       RUBY
     end
 
+    it 'registers an offense when using multiline `map { ... }.compact` as an argument of an assignment method' do
+      expect_offense(<<~RUBY)
+        object.new_collection = collection.map do |item|
+                                           ^^^^^^^^^^^^^ Use `filter_map` instead.
+        end.compact
+      RUBY
+
+      expect_correction(<<~RUBY)
+        object.new_collection = collection.filter_map do |item|
+        end
+      RUBY
+    end
+
     it 'does not register an offense when using `collection.map(&:do_something).compact!`' do
       expect_no_offenses(<<~RUBY)
         collection.map(&:do_something).compact!