diff --git a/core/file/new_spec.rb b/core/file/new_spec.rb
index 715ac1aaf3..3e2641aed3 100644
--- a/core/file/new_spec.rb
+++ b/core/file/new_spec.rb
@@ -188,6 +188,12 @@
     }.should raise_error(Errno::EEXIST, /File exists/)
   end
 
+  it "does not use the given block and warns to use File::open" do
+    -> {
+      @fh = File.new(@file) { raise }
+    }.should complain(/warning: File::new\(\) does not take block; use File::open\(\) instead/)
+  end
+
   it "raises a TypeError if the first parameter can't be coerced to a string" do
     -> { File.new(true) }.should raise_error(TypeError)
     -> { File.new(false) }.should raise_error(TypeError)
diff --git a/core/io/new_spec.rb b/core/io/new_spec.rb
index 9d14ec18ad..979ac0efcb 100644
--- a/core/io/new_spec.rb
+++ b/core/io/new_spec.rb
@@ -5,6 +5,12 @@
 
 describe "IO.new" do
   it_behaves_like :io_new, :new
+
+  it "does not use the given block and warns to use IO::open" do
+    -> {
+      @io = IO.send(@method, @fd) { raise }
+    }.should complain(/warning: IO::new\(\) does not take block; use IO::open\(\) instead/)
+  end
 end
 
 describe "IO.new" do
diff --git a/library/socket/tcpserver/new_spec.rb b/library/socket/tcpserver/new_spec.rb
index 8d9696c9d8..dd1ba676bd 100644
--- a/library/socket/tcpserver/new_spec.rb
+++ b/library/socket/tcpserver/new_spec.rb
@@ -97,6 +97,12 @@
     addr[1].should be_kind_of(Integer)
   end
 
+  it "does not use the given block and warns to use TCPServer::open" do
+    -> {
+      @server = TCPServer.new(0) { raise }
+    }.should complain(/warning: TCPServer::new\(\) does not take block; use TCPServer::open\(\) instead/)
+  end
+
   it "raises Errno::EADDRNOTAVAIL when the address is unknown" do
     -> { TCPServer.new("1.2.3.4", 0) }.should raise_error(Errno::EADDRNOTAVAIL)
   end
diff --git a/library/socket/udpsocket/new_spec.rb b/library/socket/udpsocket/new_spec.rb
index 6cc0cadbcb..79bfcb624d 100644
--- a/library/socket/udpsocket/new_spec.rb
+++ b/library/socket/udpsocket/new_spec.rb
@@ -26,6 +26,12 @@
     @socket.should be_an_instance_of(UDPSocket)
   end
 
+  it "does not use the given block and warns to use UDPSocket::open" do
+    -> {
+      @socket = UDPSocket.new { raise }
+    }.should complain(/warning: UDPSocket::new\(\) does not take block; use UDPSocket::open\(\) instead/)
+  end
+
   it 'raises Errno::EAFNOSUPPORT or Errno::EPROTONOSUPPORT if unsupported family passed' do
     -> { UDPSocket.new(-1) }.should raise_error(SystemCallError) { |e|
       [Errno::EAFNOSUPPORT, Errno::EPROTONOSUPPORT].should include(e.class)
diff --git a/library/socket/unixserver/new_spec.rb b/library/socket/unixserver/new_spec.rb
index f831f40bc6..0ff6787559 100644
--- a/library/socket/unixserver/new_spec.rb
+++ b/library/socket/unixserver/new_spec.rb
@@ -2,5 +2,13 @@
 require_relative 'shared/new'
 
 describe "UNIXServer.new" do
-  it_behaves_like :unixserver_new, :new
+  platform_is_not :windows do
+    it_behaves_like :unixserver_new, :new
+
+      it "does not use the given block and warns to use UNIXServer::open" do
+        -> {
+          @server = UNIXServer.new(@path) { raise }
+        }.should complain(/warning: UNIXServer::new\(\) does not take block; use UNIXServer::open\(\) instead/)
+      end
+  end
 end
diff --git a/library/socket/unixsocket/new_spec.rb b/library/socket/unixsocket/new_spec.rb
index 05a6b3eda2..341c922808 100644
--- a/library/socket/unixsocket/new_spec.rb
+++ b/library/socket/unixsocket/new_spec.rb
@@ -2,5 +2,13 @@
 require_relative 'shared/new'
 
 describe "UNIXSocket.new" do
-  it_behaves_like :unixsocket_new, :new
+  platform_is_not :windows do
+    it_behaves_like :unixsocket_new, :new
+
+    it "does not use the given block and warns to use UNIXSocket::open" do
+      -> {
+        @client = UNIXSocket.new(@path) { raise }
+      }.should complain(/warning: UNIXSocket::new\(\) does not take block; use UNIXSocket::open\(\) instead/)
+    end
+  end
 end