diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 9e55565..77b640e 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -3,18 +3,11 @@ name: test
 on: [push, pull_request]
 
 jobs:
-  ruby-versions:
-    uses: ruby/actions/.github/workflows/ruby_versions.yml@master
-    with:
-      engine: cruby
-      min_version: 3.0
-
   build:
-    needs: ruby-versions
     name: build (${{ matrix.ruby }} / ${{ matrix.os }})
     strategy:
       matrix:
-        ruby: ${{ fromJson(needs.ruby-versions.outputs.versions) }}
+        ruby: ["3.0", 3.1, 3.2, 3.3, 3.4]
         os: [ ubuntu-latest, macos-latest ]
     runs-on: ${{ matrix.os }}
     steps:
diff --git a/lib/set.rb b/lib/set.rb
index 295750f..ad04b85 100644
--- a/lib/set.rb
+++ b/lib/set.rb
@@ -1,11 +1,6 @@
 # frozen_string_literal: true
 
-if RUBY_VERSION >= '3.5'
-  if defined?(Set) && defined?(Set.[]) && Set.method(:[]).source_location.nil?
-    # Remove defined? ... conditional after Ruby 3.5.0-preview2
-    return
-  end
-end
+return if RUBY_VERSION >= '4'
 
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