1 files changed, 85 insertions, 3 deletions
diff --git a/spec/ruby/core/proc/parameters_spec.rb b/spec/ruby/core/proc/parameters_spec.rb
index 5fb5cf418d..972596d2ea 100644
--- a/spec/ruby/core/proc/parameters_spec.rb
+++ b/spec/ruby/core/proc/parameters_spec.rb
@@ -20,6 +20,31 @@ describe "Proc#parameters" do
     proc {|x| }.parameters.first.first.should == :opt
   end
 
+  ruby_version_is "3.2" do
+    it "sets the first element of each sub-Array to :req for required argument if lambda keyword used" do
+      proc {|x| }.parameters(lambda: true).first.first.should == :req
+      proc {|y,*x| }.parameters(lambda: true).first.first.should == :req
+    end
+
+    it "regards named parameters in procs as required if lambda keyword used" do
+      proc {|x| }.parameters(lambda: true).first.first.should == :req
+    end
+
+    it "regards named parameters in lambda as optional if lambda: false keyword used" do
+      -> x { }.parameters(lambda: false).first.first.should == :opt
+    end
+
+    it "regards named parameters in procs and lambdas as required if lambda keyword is truthy" do
+      proc {|x| }.parameters(lambda: 123).first.first.should == :req
+      -> x { }.parameters(lambda: 123).first.first.should == :req
+    end
+
+    it "ignores the lambda keyword if it is nil" do
+      proc {|x|}.parameters(lambda: nil).first.first.should == :opt
+      -> x { }.parameters(lambda: nil).first.first.should == :req
+    end
+  end
+
   it "regards optional keyword parameters in procs as optional" do
     proc {|x: :y| }.parameters.first.first.should == :key
   end
@@ -76,12 +101,39 @@ describe "Proc#parameters" do
     proc {|&block| }.parameters.first.last.should == :block
   end
 
-  it "ignores unnamed rest args" do
+  it "ignores unnamed rest arguments" do
     -> x {}.parameters.should == [[:req, :x]]
   end
 
-  it "adds nameless rest arg for \"star\" argument" do
-    -> x, * {}.parameters.should == [[:req, :x], [:rest]]
+  it "ignores implicit rest arguments" do
+    proc { |x, | }.parameters.should == [[:opt, :x]]
+    -> x { }.parameters.should == [[:req, :x]]
+  end
+
+  ruby_version_is '3.2' do
+    it "adds rest arg with name * for \"star\" argument" do
+      -> * {}.parameters.should == [[:rest, :*]]
+    end
+
+    it "adds keyrest arg with ** as a name for \"double star\" argument" do
+      -> ** {}.parameters.should == [[:keyrest, :**]]
+    end
+  end
+
+  ruby_version_is ''...'3.2' do
+    it "adds nameless rest arg for \"star\" argument" do
+      -> * {}.parameters.should == [[:rest]]
+    end
+
+    it "adds nameless keyrest arg for \"double star\" argument" do
+      -> ** {}.parameters.should == [[:keyrest]]
+    end
+  end
+
+  ruby_version_is '3.1' do
+    it "adds block arg with name & for anonymous block argument" do
+      eval('-> & {}.parameters').should == [[:block, :&]]
+    end
   end
 
   it "does not add locals as block options with a block and splat" do
@@ -92,4 +144,34 @@ describe "Proc#parameters" do
       local_is_not_parameter = {}
     end.parameters.should == [[:rest, :args], [:block, :blk]]
   end
+
+  it "returns all parameters defined with the name _ as _" do
+    proc = proc {|_, _, _ = 1, *_, _:, _: 2, **_, &_| }
+    proc.parameters.should == [
+      [:opt, :_],
+      [:opt, :_],
+      [:opt, :_],
+      [:rest, :_],
+      [:keyreq, :_],
+      [:key, :_],
+      [:keyrest, :_],
+      [:block, :_]
+    ]
+
+    lambda = -> _, _, _ = 1, *_, _:, _: 2, **_, &_ {}
+    lambda.parameters.should == [
+      [:req, :_],
+      [:req, :_],
+      [:opt, :_],
+      [:rest, :_],
+      [:keyreq, :_],
+      [:key, :_],
+      [:keyrest, :_],
+      [:block, :_]
+    ]
+  end
+
+  it "returns :nokey for **nil parameter" do
+    proc { |**nil| }.parameters.should == [[:nokey]]
+  end
 end