Merge pull request #2312 from kachick/fix-symbol-to_proc

Returned Proc of Symbol#to_proc should raise an ArgumentError when calling #call without receiver parameter

kernel/common/symbol18.rb

@@ -26,6 +26,9 @@ def to_proc
     # we leave the symbol in sym and use it in the block.
     #
     sym = self
-    Proc.new { |*args| args.shift.__send__(sym, *args) }
+    Proc.new do |*args|
+      raise ArgumentError, "no receiver given" if args.empty?
+      args.shift.__send__(sym, *args)
+    end
   end
 end

kernel/common/symbol19.rb

@@ -113,6 +113,9 @@ def to_proc
     # we leave the symbol in sym and use it in the block.
     #
     sym = self
-    Proc.new { |*args, &b| args.shift.__send__(sym, *args, &b) }
+    Proc.new do |*args, &b|
+      raise ArgumentError, "no receiver given" if args.empty?
+      args.shift.__send__(sym, *args, &b)
+    end
   end
 end

spec/ruby/core/symbol/to_proc_spec.rb

@@ -12,6 +12,10 @@
       obj.should_receive(:to_s).and_return("Received #to_s")
       :to_s.to_proc.call(obj).should == "Received #to_s"
     end
+
+    it "raises an ArgumentError when calling #call on the Proc without receiver" do
+      lambda { :object_id.to_proc.call }.should raise_error(ArgumentError)
+    end
   end
 
   describe "Symbol#to_proc" do