diff --git a/lib/bundler/definition.rb b/lib/bundler/definition.rb
index 4162e19c5e..ca12827579 100644
--- a/lib/bundler/definition.rb
+++ b/lib/bundler/definition.rb
@@ -245,8 +245,9 @@ module Bundler
     end
 
     def filter_relevant(dependencies)
+      platforms_array = [generic_local_platform].freeze
       dependencies.select do |d|
-        d.should_include? && !d.gem_platforms([generic_local_platform]).empty?
+        d.should_include? && !d.gem_platforms(platforms_array).empty?
       end
     end
 
@@ -270,9 +271,15 @@ module Bundler
 
     def dependencies_for(groups)
       groups.map!(&:to_sym)
-      current_dependencies.reject do |d|
-        (d.groups & groups).empty?
+      deps = current_dependencies # always returns a new array
+      deps.select! do |d|
+        if RUBY_VERSION >= "3.1"
+          d.groups.intersect?(groups)
+        else
+          !(d.groups & groups).empty?
+        end
       end
+      deps
     end
 
     # Resolve all the dependencies specified in Gemfile. It ensures that
diff --git a/lib/bundler/dependency.rb b/lib/bundler/dependency.rb
index 21a4564dcc..82c4c1866b 100644
--- a/lib/bundler/dependency.rb
+++ b/lib/bundler/dependency.rb
@@ -48,10 +48,13 @@ module Bundler
       @autorequire = Array(options["require"] || []) if options.key?("require")
     end
 
+    RUBY_PLATFORM_ARRAY = [Gem::Platform::RUBY].freeze
+    private_constant :RUBY_PLATFORM_ARRAY
+
     # Returns the platforms this dependency is valid for, in the same order as
     # passed in the `valid_platforms` parameter
     def gem_platforms(valid_platforms)
-      return [Gem::Platform::RUBY] if force_ruby_platform
+      return RUBY_PLATFORM_ARRAY if force_ruby_platform
       return valid_platforms if @platforms.empty?
 
       valid_platforms.select {|p| expanded_platforms.include?(GemHelpers.generic(p)) }