CI fixes (3)

[CMake] Add boost core to dependency list

.travis.yml

@@ -2,38 +2,17 @@
 # subject to the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 #
-# Copyright Antony Polukhin 2014-2018.
+# Copyright Antony Polukhin 2014-2020.
 
 #
 # See https://svn.boost.org/trac/boost/wiki/TravisCoverals for description of this file
 # and how it can be used with Boost libraries.
 #
-# File revision #9
+# File revision #10
 
-sudo: false
 language: cpp
 os: linux
 
-env:
-  global:
-    # Autodetect Boost branch by using the following code: - BOOST_BRANCH=$TRAVIS_BRANCH
-    # or just directly specify it
-    - BOOST_BRANCH=develop && [ "$TRAVIS_BRANCH" == "master" ] && BOOST_BRANCH=master || true
-
-    # Files, which coverage results must be ignored (files from other projects).
-    # Example: - IGNORE_COVERAGE='*/boost/progress.hpp */filesystem/src/*'
-    - IGNORE_COVERAGE=''
-
-    # boost-local/libs/ folder to put this library into. This may be useful, if you're for example running Travis
-    # from `Boost.DLL` repo while Boost already has `dll` and with to replace `dll` with content of`Boost.DLL`.
-    #
-    # Otherwise just leave the default value - BOOST_LIBS_FOLDER=$(basename $TRAVIS_BUILD_DIR)
-    - BOOST_LIBS_FOLDER=$(basename $TRAVIS_BUILD_DIR)
-
-    # Global options for sanitizers
-    - UBSAN_OPTIONS=print_stacktrace=1
-    - LSAN_OPTIONS=verbosity=1:log_threads=1
-
 # `--coverage` flags required to generate coverage info for Coveralls
 matrix:
   include:
@@ -60,13 +39,13 @@ matrix:
 #          sources: ubuntu-toolchain-r-test
 #          packages: g++-8
 
-    - env: B2_ARGS='cxxstd=98,03,11,14,1z toolset=clang-5 cxxflags="--coverage -fsanitize=address,leak,undefined -fno-sanitize-recover=undefined -DBOOST_TRAVISCI_BUILD" linkflags="--coverage -fsanitize=address,leak,undefined"'
-      name: "Clang-5"
+    - env: B2_ARGS='cxxstd=98,03,11,14,1z toolset=clang-7 cxxflags="--coverage -fsanitize=address,leak,undefined -fno-sanitize-recover=undefined -DBOOST_TRAVISCI_BUILD" linkflags="--coverage -fsanitize=address,leak,undefined"'
+      name: "Clang-7"
       sudo: required # Required by leak sanitizer
       addons:
         apt:
-          sources: llvm-toolchain-trusty-5.0
-          packages: clang-5.0
+          sources: llvm-toolchain-trusty-7
+          packages: clang++-7
 
     - env: B2_ARGS='cxxstd=03,11,14 toolset=clang-libc++ cxxflags="--coverage -fsanitize=address,leak,undefined -fno-sanitize-recover=undefined -DBOOST_TRAVISCI_BUILD" linkflags="--coverage -fsanitize=address,leak,undefined"'
       name: "Clang-3.8, libc++"
@@ -88,22 +67,41 @@ addons:
     - python-yaml
 
 before_install:
+  # Autodetect Boost branch by using the following code: - BOOST_BRANCH=$TRAVIS_BRANCH
+  # or just directly specify it
+  - BOOST_BRANCH=develop && [ "$TRAVIS_BRANCH" == "master" ] && BOOST_BRANCH=master || true
+
+  # Files, which coverage results must be ignored (files from other projects).
+  # Example: - IGNORE_COVERAGE='*/boost/progress.hpp */filesystem/src/*'
+  - IGNORE_COVERAGE=''
+
+  # boost-local/libs/ folder to put this library into. This may be useful, if you're for example running Travis
+  # from `Boost.DLL` repo while Boost already has `dll` and with to replace `dll` with content of`Boost.DLL`.
+  #
+  # Otherwise just leave the default value - BOOST_LIBS_FOLDER=$(basename $TRAVIS_BUILD_DIR)
+  - BOOST_LIBS_FOLDER=$(basename $TRAVIS_BUILD_DIR)
+
+  # Global options for sanitizers
+  - UBSAN_OPTIONS=print_stacktrace=1
+  - LSAN_OPTIONS=verbosity=1:log_threads=1
   # Cloning minimal set of Boost libraries
   - BOOST=$HOME/boost-local
-  - git clone -b $BOOST_BRANCH --depth 1 https://github.com/boostorg/boost.git $BOOST
+  - git clone -b $BOOST_BRANCH --depth 10 https://github.com/boostorg/boost.git $BOOST
   - cd $BOOST
-  - git submodule update --init --depth 1 tools/build tools/boostdep
+  - git submodule update --init --depth 10 --jobs 2 tools/build tools/boostdep tools/inspect libs/filesystem
+  - python tools/boostdep/depinst/depinst.py --git_args "--depth 10 --jobs 2" $BOOST/libs/filesystem
 
   # Replacing Boost module with this project and installing Boost dependencies
   - echo "Testing $BOOST/libs/$BOOST_LIBS_FOLDER moved from $TRAVIS_BUILD_DIR, branch $BOOST_BRANCH"
   - rm -rf $BOOST/libs/$BOOST_LIBS_FOLDER || true
   - mv $TRAVIS_BUILD_DIR $BOOST/libs/$BOOST_LIBS_FOLDER
-  - python tools/boostdep/depinst/depinst.py --git_args "--depth 1 --jobs 2" $BOOST_LIBS_FOLDER
+  - python tools/boostdep/depinst/depinst.py --git_args "--depth 10 --jobs 2" $BOOST_LIBS_FOLDER
   - git status
 
   # Adding missing toolsets and preparing Boost headers
   - ./bootstrap.sh
   - ./b2 headers
+  - ./b2 -j4 variant=debug tools/inspect/build
   - |-
     echo "using gcc ;" >> ~/user-config.jam
     echo "using clang ;" >> ~/user-config.jam
@@ -111,13 +109,14 @@ before_install:
     echo "using clang : 4 : clang++-4.0 ;" >> ~/user-config.jam
     echo "using clang : 5 : clang++-5.0 ;" >> ~/user-config.jam
     echo "using clang : 6 : clang++-6.0 ;" >> ~/user-config.jam
-    echo "using clang : 7 : clang++-7.0 ;" >> ~/user-config.jam
-    echo "using clang : 8 : clang++-8.0 ;" >> ~/user-config.jam
+    echo "using clang : 7 : clang++-7 ;" >> ~/user-config.jam
+    echo "using clang : 8 : clang++-8 ;" >> ~/user-config.jam
     echo "using clang : libc++ : clang++-libc++ ;" >> ~/user-config.jam
   - cd $BOOST/libs/$BOOST_LIBS_FOLDER/test/
 
 script:
   - sh -c "../../../b2 -j2 $B2_ARGS"
+  - ../../../dist/bin/inspect .. -license -copyright -crlf -end -path_name -tab -ascii -apple_macro -assert_macro -deprecated_macro -minmax -unnamed
 
 after_success:
   # Copying Coveralls data to a separate folder

CMakeLists.txt

@@ -17,6 +17,7 @@ target_link_libraries( boost_conversion
     INTERFACE
         Boost::assert
         Boost::config
+        Boost::core
         Boost::smart_ptr
         Boost::throw_exception
         Boost::type_traits

doc/conversion.qbk

@@ -1,5 +1,7 @@
 [/
     Copyright 2016 Mikhail Maximov.
+    Copyright 2020 Antony Polukhin.
+
     Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)
 ]
@@ -8,15 +10,15 @@
     [quickbook 1.6]
     [compatibility-mode 1.5]
     [id conversion]
-    [version 1.6]
+    [version 1.7]
     [authors [Stroustrup, Bjarne], [Abrahams, Dave], [Rasin, Boris], [Polukhin, Antony]]
-    [copyright 2001 Beman Dawes, 2014-2019 Antony Polukhin]
+    [copyright 2001 Beman Dawes, 2014-2020 Antony Polukhin]
     [license
         Distributed under the Boost Software License, Version 1.0.
         (See accompanying file LICENSE_1_0.txt or copy at
         [@http://www.boost.org/LICENSE_1_0.txt])
     ]
-    [source-mode teletype]
+    [source-mode c++]
 ]
 
 [/ QuickBook Document version 1.5 ]
@@ -44,7 +46,7 @@ the Boost Conversion Library is supplied by several headers:
   provides [@boost:libs/lexical_cast/doc/html/index.html `lexical_cast<>`] general literal text conversions, such as an `int` represented as a `string`, or vice-versa. 
 
 [endsect]
-  
+
 [section Polymorphic casts]
 Pointers to polymorphic objects (objects of classes which define at
 least one virtual function) are sometimes downcast or crosscast.
@@ -58,6 +60,7 @@ safety, suffer poor readability, and are difficult to locate with search
 tools.
 
 [#polymorphic_downcast]
+[section polymorphic_downcast]
 
 The C++ built-in `static_cast` can be used for efficiently
 downcasting pointers to polymorphic objects, but provides no error
@@ -68,11 +71,11 @@ debug compilations adds safety via an `assert()` that a `dynamic_cast`
 succeeds.
 
 A `polymorphic_downcast` should be used for
-downcasts that you are certain should succeed.  Error checking is
+downcasts that you are certain should succeed. Error checking is
 only performed in translation units where `NDEBUG` is
 not defined, via
 ```
-	assert( dynamic_cast<Derived>(x) == x )
+    assert( dynamic_cast<Derived>(x) == x )
 ```
 where `x` is the source pointer.  This approach
 ensures that not only is a non-zero pointer returned, but also
@@ -81,10 +84,26 @@ Attempts to crosscast using `polymorphic_downcast` will
 fail to compile.
 
 [warning Because `polymorphic_downcast` uses `assert()`, it
-violates the One Definition Rule (ODR) if NDEBUG is inconsistently
+violates the One Definition Rule (ODR) if `NDEBUG` is inconsistently
 defined across translation units. See ISO Std 3.2]
 
+[h4 Example:]
+```
+    #include <boost/polymorphic_cast.hpp>
+    ...
+    class Fruit { public: virtual ~Fruit(){}; ... };
+    class Banana : public Fruit { ... };
+    ...
+    void f( Fruit * fruit ) {
+      // ... logic which leads us to believe it is a Banana
+      Banana * banana = boost::polymorphic_downcast<Banana*>(fruit);
+      ...
+    }
+```
+[endsect]
+
 [#polymorphic_cast]
+[section polymorphic_cast]
 
 The C++ built-in `dynamic_cast` can be used for downcasts and
 crosscasts of pointers to polymorphic objects, but error notification in
@@ -102,88 +121,88 @@ or when efficiency is not important, `polymorphic_cast` is preferred.
 The C++ built-in `dynamic_cast` must be used to cast references rather than pointers.
 It is also the only cast that can be used to check whether a given interface is supported; in that case a return of 0 isn't an error condition.
 
+[endsect]
+
+
 [#polymorphic_pointer_cast]
+[section polymorphic_pointer_cast]
 While `polymorphic_downcast` and `polymorphic_cast` work with built-in pointer types only,
 `polymorphic_pointer_downcast` and `polymorphic_pointer_cast` are more generic versions
 with support for any pointer type for which the following expressions would be valid:
 
 For `polymorphic_pointer_downcast`:
 ```
-	static_pointer_cast<Derived>(p);
-	dynamic_pointer_cast<Derived>(p);
+    static_pointer_cast<Derived>(p);
+    dynamic_pointer_cast<Derived>(p);
 ```
 For `polymorphic_pointer_cast`:
 ```
-	dynamic_pointer_cast<Derived>(p);
-	!p; // conversion to bool with negation
+    dynamic_pointer_cast<Derived>(p);
+    !p; // conversion to bool with negation
 ```
 
 This includes C++ built-in pointers, `std::shared_ptr`,
 `boost::shared_ptr`, `boost::intrusive_ptr`, etc.
 
-[endsect]
-[section `polymorphic_cast`, `polymorphic_downcast`, `polymorphic_pointer_cast` and `polymorphic_pointer_downcast` synopsis]
+
+[h4 Example:]
 ```
-	namespace boost {
+    #include <boost/polymorphic_pointer_cast.hpp>
 
-	template <class Derived, class Base>
-	inline Derived polymorphic_cast(Base* x);
-	// Throws: std::bad_cast if ( dynamic_cast<Derived>(x) == 0 )
-	// Returns: dynamic_cast<Derived>(x)
+    class Fruit { public: virtual ~Fruit(){} };
+    class Banana : public Fruit {};
 
-	template <class Derived, class Base>
-	inline Derived polymorphic_downcast(Base* x);
-	// Effects: assert( dynamic_cast<Derived>(x) == x );
-	// Returns: static_cast<Derived>(x)
+    // Use one of these:
+    typedef Fruit* FruitPtr;
+    typedef std::shared_ptr<Fruit> FruitPtr;
+    typedef boost::shared_ptr<Fruit> FruitPtr;
+    typedef boost::intrusive_ptr<Fruit> FruitPtr;
 
-	template <class Derived, class Base>
-	inline auto polymorphic_pointer_cast(Base x);
-	// Throws: std::bad_cast if ( dynamic_pointer_cast<Derived>(x) == 0 )
-	// Returns: dynamic_pointer_cast<Derived>(x)
+    void f(FruitPtr fruit) {
+      // ... logic which leads us to believe it is a banana
+      auto banana = boost::polymorphic_pointer_downcast<Banana>(fruit);
+      ...
+    }
+```
 
-	template <class Derived, class Base>
-	inline auto polymorphic_pointer_downcast(Base x);
-	// Effects: assert( dynamic_pointer_cast<Derived>(x) == x );
-	// Returns: static_pointer_cast<Derived>(x)
+[endsect]
 
-	}
+[endsect]
+
+[section Synopsis]
+```
+    namespace boost {
+
+    // Throws: std::bad_cast if ( dynamic_cast<Derived>(x) == 0 )
+    // Returns: dynamic_cast<Derived>(x)
+    template <class Derived, class Base>
+    inline Derived polymorphic_cast(Base* x);
+
+    // Effects: assert( dynamic_cast<Derived>(x) == x );
+    // Returns: static_cast<Derived>(x)
+    template <class Derived, class Base>
+    inline Derived polymorphic_downcast(Base* x);
+
+    // Effects: assert( dynamic_cast<Derived>(&x) == &x );
+    // Returns: static_cast<Derived>(x)
+    template <class Derived, class Base>
+    inline Derived polymorphic_downcast(Base& x);
+
+    // Throws: std::bad_cast if ( dynamic_pointer_cast<Derived>(x) == 0 )
+    // Returns: dynamic_pointer_cast<Derived>(x)
+    template <class Derived, class Base>
+    inline auto polymorphic_pointer_cast(Base x);
+
+    // Effects: assert( dynamic_pointer_cast<Derived>(x) == x );
+    // Returns: static_pointer_cast<Derived>(x)
+    template <class Derived, class Base>
+    inline auto polymorphic_pointer_downcast(Base x);
+
+    }
 ```
 [endsect]
-[section `polymorphic_downcast` example]
-```
-	#include <boost/polymorphic_cast.hpp>
-	...
-	class Fruit { public: virtual ~Fruit(){}; ... };
-	class Banana : public Fruit { ... };
-	...
-	void f( Fruit * fruit ) {
-	  // ... logic which leads us to believe it is a Banana
-	  Banana * banana = boost::polymorphic_downcast<Banana*>(fruit);
-	  ...
-	}
-```
-[endsect]
-[section `polymorphic_pointer_downcast` example]
-```
-	#include <boost/polymorphic_pointer_cast.hpp>
 
-	class Fruit { public: virtual ~Fruit(){} };
-	class Banana : public Fruit {};
 
-	// use one of these:
-
-	typedef Fruit* FruitPtr;
-	typedef std::shared_ptr<Fruit> FruitPtr;
-	typedef boost::shared_ptr<Fruit> FruitPtr;
-	typedef boost::intrusive_ptr<Fruit> FruitPtr;
-
-	void f(FruitPtr fruit) {
-	  // ... logic which leads us to believe it is a banana
-	  auto banana = boost::polymorphic_pointer_downcast<Banana>(fruit);
-	  ...
-	}
-```
-[endsect]
 [section History]
 `polymorphic_cast` was suggested by Bjarne Stroustrup in "The C++ Programming Language".
 
@@ -192,6 +211,8 @@ This includes C++ built-in pointers, `std::shared_ptr`,
 `polymorphic_pointer_downcast` was contributed by [@http://www.boost.org/people/boris_rasin.htm Boris Rasin]
 and `polymorphic_pointer_cast` by Antony Polukhin.
 
+`polymorphic_downcast` overload for references was contributed by Julien Delacroix.
+
 An old `numeric_cast` that was contributed by [@http://www.boost.org/people/kevlin_henney.htm Kevlin Henney]
-is now superseeded by the [@boost:numeric_conversion/doc/html/html/boost_numericconversion/improved_numeric_cast__.html Boost Numeric Conversion Library]
+is now superseded by the [@boost:numeric_conversion/doc/html/html/boost_numericconversion/improved_numeric_cast__.html Boost Numeric Conversion Library]
 [endsect]

include/boost/implicit_cast.hpp

@@ -2,8 +2,9 @@
 // Distributed under the Boost Software License, Version 1.0. (See
 // accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
-#ifndef IMPLICIT_CAST_DWA200356_HPP
-# define IMPLICIT_CAST_DWA200356_HPP
+
+#ifndef BOOST_IMPLICIT_CAST_DWA200356_HPP
+#define BOOST_IMPLICIT_CAST_DWA200356_HPP
 
 namespace boost {
 
@@ -26,11 +27,7 @@ inline T implicit_cast (typename boost::detail::icast_identity<T>::type x) {
     return x;
 }
 
-// incomplete return type now is here
-//template <typename T>
-//void implicit_cast (...);
-
 } // namespace boost
 
 
-#endif // IMPLICIT_CAST_DWA200356_HPP
+#endif // BOOST_IMPLICIT_CAST_DWA200356_HPP

include/boost/polymorphic_cast.hpp

@@ -50,14 +50,20 @@
 #define BOOST_POLYMORPHIC_CAST_HPP
 
 # include <boost/config.hpp>
-# include <boost/assert.hpp>
-# include <boost/throw_exception.hpp>
-# include <typeinfo>
 
 #ifdef BOOST_HAS_PRAGMA_ONCE
 #   pragma once
 #endif
 
+# include <boost/assert.hpp>
+# include <boost/core/addressof.hpp>
+# include <boost/core/enable_if.hpp>
+# include <boost/throw_exception.hpp>
+# include <boost/type_traits/is_reference.hpp> 
+# include <boost/type_traits/remove_reference.hpp>
+
+# include <typeinfo>
+
 namespace boost
 {
 //  See the documentation for descriptions of how to choose between
@@ -79,7 +85,7 @@ namespace boost
 
 //  polymorphic_downcast  ----------------------------------------------------//
 
-    //  BOOST_ASSERT() checked polymorphic downcast.  Crosscasts prohibited.
+    //  BOOST_ASSERT() checked raw pointer polymorphic downcast.  Crosscasts prohibited.
 
     //  WARNING: Because this cast uses BOOST_ASSERT(), it violates
     //  the One Definition Rule if used in multiple translation units
@@ -95,6 +101,26 @@ namespace boost
         return static_cast<Target>(x);
     }
 
+    //  BOOST_ASSERT() checked reference polymorphic downcast.  Crosscasts prohibited.
+
+    //  WARNING: Because this cast uses BOOST_ASSERT(), it violates
+    //  the One Definition Rule if used in multiple translation units
+    //  where BOOST_DISABLE_ASSERTS, BOOST_ENABLE_ASSERT_HANDLER
+    //  NDEBUG are defined inconsistently.
+
+    //  Contributed by Julien Delacroix
+
+    template <class Target, class Source>
+    inline typename boost::enable_if_c<
+        boost::is_reference<Target>::value, Target
+    >::type polymorphic_downcast(Source& x)
+    {
+        typedef typename boost::remove_reference<Target>::type* target_pointer_type;
+        return *boost::polymorphic_downcast<target_pointer_type>(
+            boost::addressof(x)
+        );
+    }
+
 } // namespace boost
 
 #endif  // BOOST_POLYMORPHIC_CAST_HPP

index.html

@@ -29,7 +29,7 @@
     <a href="../../doc/html/conversion.html">../../doc/html/conversion.html</a>
   </p>
   <p>
-    &copy; 2014 Antony Polukhin
+    &copy; 2014-2020 Antony Polukhin
   </p>
 </body>
-</html>
+</html>

test/appveyor.yml

@@ -2,7 +2,7 @@
 # subject to the Boost Software License, Version 1.0. (See accompanying
 # file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 #
-# Copyright Antony Polukhin 2016-2018.
+# Copyright Antony Polukhin 2016-2019.
 
 #
 # See https://svn.boost.org/trac/boost/wiki/TravisCoverals for description of this file
@@ -21,7 +21,7 @@ init:
 # From this point and below code is same for all the Boost libs
 ###############################################################################################################
 
-version: 1.64.{build}-{branch}
+version: 1.71.{build}-{branch}
  
 # branches to build
 branches:
@@ -32,25 +32,25 @@ skip_tags: true
 
 environment:
   matrix:
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       TOOLSET: msvc-9.0,msvc-10.0,msvc-11.0,msvc-12.0
     - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2017
       TOOLSET: msvc-14.1,clang-win
       CXXSTD: 14,17
       ADDRMD: 32,64
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       ADDPATH: C:\cygwin\bin;
       TOOLSET: gcc
       CXXSTD: 03,11,14,1z
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       ADDPATH: C:\cygwin64\bin;
       TOOLSET: gcc
       CXXSTD: 03,11,14,1z
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       ADDPATH: C:\mingw\bin;
       TOOLSET: gcc
       CXXSTD: 03,11,14,1z
-    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2013
+    - APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
       ADDPATH: C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin;
       TOOLSET: gcc
       CXXSTD: 03,11,14,1z
@@ -61,9 +61,9 @@ before_build:
     - echo "Testing %APPVEYOR_PROJECT_NAME%"
     # Cloning Boost libraries (fast nondeep cloning)
     - set BOOST=C:/boost-local
-    - git clone -b %BOOST_BRANCH% --depth 1 https://github.com/boostorg/boost.git %BOOST%
+    - git clone -b %BOOST_BRANCH% --depth 10 https://github.com/boostorg/boost.git %BOOST%
     - cd %BOOST%
-    - git submodule update --init --depth 1 tools/build tools/boostdep
+    - git submodule update --init --depth 10 tools/build tools/boostdep
 
     - rm -rf %BOOST%/libs/%BOOST_LIBS_FOLDER%
     - mv -f %APPVEYOR_BUILD_FOLDER% %BOOST%/libs/%BOOST_LIBS_FOLDER%

test/polymorphic_cast_test.cpp

@@ -172,20 +172,23 @@ static void test_polymorphic_pointer_cast()
 
 static void test_polymorphic_downcast()
 {
-    Base * base = new Derived;
+    Base *base_pointer = new Derived;
 
-    Derived * derived = boost::polymorphic_downcast<Derived*>( base );
+    // test raw pointer cast
+    Derived *derived_pointer = boost::polymorphic_downcast<Derived *>(base_pointer);
 
-    BOOST_TEST( derived != 0 );
+    BOOST_TEST(derived_pointer != 0);
 
-    if( derived != 0 )
+    if (derived_pointer != 0)
     {
-        BOOST_TEST_EQ( derived->kind(), "Derived" );
+        BOOST_TEST_EQ(derived_pointer->kind(), "Derived");
     }
 
-    // polymorphic_downcast can't do crosscasts
+    // test reference cast
+    Derived& derived_ref = boost::polymorphic_downcast<Derived&>(*base_pointer);
+    BOOST_TEST_EQ(derived_ref.kind(), "Derived");
 
-    delete base;
+    delete base_pointer;
 }
 
 static void test_polymorphic_pointer_downcast_builtin()
@@ -278,17 +281,32 @@ static void test_polymorphic_pointer_cast_fail()
 
 static void test_polymorphic_downcast_fail()
 {
-    Base * base = new Base;
+    Base * base_pointer = new Base;
 
-    int old_count = assertion_failed_count;
-    expect_assertion = true;
+    {
+        // test raw pointer cast
 
-    BOOST_TEST_THROWS( boost::polymorphic_downcast<Derived*>( base ), expected_assertion ); // should assert
+        int old_count = assertion_failed_count;
+        expect_assertion = true;
 
-    BOOST_TEST_EQ( assertion_failed_count, old_count + 1 );
-    expect_assertion = false;
+        BOOST_TEST_THROWS(boost::polymorphic_downcast<Derived *>(base_pointer), expected_assertion); // should assert
 
-    delete base;
+        BOOST_TEST_EQ(assertion_failed_count, old_count + 1);
+        expect_assertion = false;
+    }
+    {
+        // test reference cast
+
+        int old_count = assertion_failed_count;
+        expect_assertion = true;
+
+        BOOST_TEST_THROWS(boost::polymorphic_downcast<Derived &>(*base_pointer), expected_assertion); // should assert
+
+        BOOST_TEST_EQ(assertion_failed_count, old_count + 1);
+        expect_assertion = false;
+    }
+
+    delete base_pointer;
 }
 
 static void test_polymorphic_pointer_downcast_builtin_fail()