From ed5c108802bab7c5baaf04298da7f8f369c28f48 Mon Sep 17 00:00:00 2001
From: Koichi ITO <koic.ito@gmail.com>
Date: Sat, 19 Aug 2023 14:44:12 +0900
Subject: [PATCH] [Fix #365] Fix false positives for
 `Performance/ArraySemiInfiniteRangeSlice`

Fixes #365.

This PR fixes false positives for `Performance/ArraySemiInfiniteRangeSlice`
when using `[]` with string literals.
What this can do is accept string literals, as they are already marked as unsafe.
---
 ...formance_array_semi_infinite_range_slice.md |  1 +
 .../array_semi_infinite_range_slice.rb         |  2 +-
 .../array_semi_infinite_range_slice_spec.rb    | 18 ++++++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)
 create mode 100644 changelog/fix_false_positives_for_performance_array_semi_infinite_range_slice.md

diff --git a/changelog/fix_false_positives_for_performance_array_semi_infinite_range_slice.md b/changelog/fix_false_positives_for_performance_array_semi_infinite_range_slice.md
new file mode 100644
index 0000000000..27fa490e5d
--- /dev/null
+++ b/changelog/fix_false_positives_for_performance_array_semi_infinite_range_slice.md
@@ -0,0 +1 @@
+* [#365](https://github.com/rubocop/rubocop-performance/issues/365): Fix false positives for `Performance/ArraySemiInfiniteRangeSlice` when using `[]` with string literals. ([@koic][])
diff --git a/lib/rubocop/cop/performance/array_semi_infinite_range_slice.rb b/lib/rubocop/cop/performance/array_semi_infinite_range_slice.rb
index eaee567d77..3658ab3e79 100644
--- a/lib/rubocop/cop/performance/array_semi_infinite_range_slice.rb
+++ b/lib/rubocop/cop/performance/array_semi_infinite_range_slice.rb
@@ -39,7 +39,7 @@ class ArraySemiInfiniteRangeSlice < Base
         RESTRICT_ON_SEND = SLICE_METHODS
 
         def_node_matcher :endless_range_slice?, <<~PATTERN
-          (call $_ $%SLICE_METHODS $#endless_range?)
+          (call $!{str dstr xstr} $%SLICE_METHODS $#endless_range?)
         PATTERN
 
         def_node_matcher :endless_range?, <<~PATTERN
diff --git a/spec/rubocop/cop/performance/array_semi_infinite_range_slice_spec.rb b/spec/rubocop/cop/performance/array_semi_infinite_range_slice_spec.rb
index fe528119dd..399d299a73 100644
--- a/spec/rubocop/cop/performance/array_semi_infinite_range_slice_spec.rb
+++ b/spec/rubocop/cop/performance/array_semi_infinite_range_slice_spec.rb
@@ -77,5 +77,23 @@
         array[-2..]
       RUBY
     end
+
+    it 'does not registers an offense when using `[]` with endless range for string literal' do
+      expect_no_offenses(<<~RUBY)
+        'str'[3..]
+      RUBY
+    end
+
+    it 'does not registers an offense when using `[]` with endless range for interpolated string literal' do
+      expect_no_offenses(<<~'RUBY')
+        "string#{interpolation}"[3..]
+      RUBY
+    end
+
+    it 'does not registers an offense when using `[]` with endless range for backquote string literal' do
+      expect_no_offenses(<<~RUBY)
+        `str`[3..]
+      RUBY
+    end
   end
 end