diff --git a/example/features/ifdef.cpp b/example/features/ifdef.cpp
index 6cf52e0..1736f32 100644
--- a/example/features/ifdef.cpp
+++ b/example/features/ifdef.cpp
@@ -125,7 +125,7 @@ public:
             boost::contract::guard c = boost::contract::constructor(this)
                 #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
                     .postcondition([&] {
-                        BOOST_CONTRACT_ASSERT(size() == (to - from + 1));
+                        BOOST_CONTRACT_ASSERT(int(size()) == (to - from + 1));
                     })
                 #endif
             ;
diff --git a/example/n1962/vector.cpp b/example/n1962/vector.cpp
index 52ef7cb..c27aa85 100644
--- a/example/n1962/vector.cpp
+++ b/example/n1962/vector.cpp
@@ -658,7 +658,9 @@ int main() {
     vector<x> z(y);
 
     typename vector<x>::iterator j = y.begin();
+    assert(j != y.end());
     typename vector<x>::const_iterator cj = cy.begin();
+    assert(cj != cy.end());
 
     y.insert(j, 2, x());
     y.push_back(x());
diff --git a/include/boost/contract.hpp b/include/boost/contract.hpp
index 4524ced..b56ca51 100644
--- a/include/boost/contract.hpp
+++ b/include/boost/contract.hpp
@@ -37,9 +37,9 @@ never be used directly by programmers.
 #include <boost/contract/override.hpp>
 #include <boost/contract/public_function.hpp>
 
-// TODO: Review all warnings for examples, tests, and also lib compilation...
-
 // TODO: Add all copyright and licencing info (to all files, etc.).
 
+// TODO: Document that the correct way of programming contracts for overridden protected and overriding public functions is as follows: Both must use virtual_ (otherwise C++ won't override because mismatching parameters), but overridden protected does not use public_function. See test/public_function/protected.cpp.
+
 #endif // #include guard
 
diff --git a/include/boost/contract/core/exception.hpp b/include/boost/contract/core/exception.hpp
index ec43544..6e85d35 100644
--- a/include/boost/contract/core/exception.hpp
+++ b/include/boost/contract/core/exception.hpp
@@ -48,6 +48,12 @@ public:
     virtual ~exception() /** @cond */ BOOST_NOEXCEPT_OR_NOTHROW /** @endcond */;
 };
 
+#ifdef BOOST_MSVC
+    #pragma warning(push)
+    #pragma warning(disable: 4275) // Bases w/o DLL spec (bad_cast, etc).
+    #pragma warning(disable: 4251) // Members w/o DLL spec (string for what_).
+#endif
+
 /**
 Exception thrown when inconsistent return values are passed to overridden
 virtual public functions.
@@ -181,6 +187,10 @@ private:
 /** @endcond */
 };
 
+#ifdef BOOST_MSVC
+    #pragma warning(pop)
+#endif
+
 /**
 Represent the operation where the contract assertion failed.
 This is passed as a parameter to the assertion failure handler functions.
diff --git a/include/boost/contract/detail/check_guard.hpp b/include/boost/contract/detail/check_guard.hpp
index 9b40c2c..489326a 100644
--- a/include/boost/contract/detail/check_guard.hpp
+++ b/include/boost/contract/detail/check_guard.hpp
@@ -15,6 +15,11 @@
 
 namespace boost { namespace contract { namespace detail {
 
+#ifdef BOOST_MSVC
+    #pragma warning(push)
+    #pragma warning(disable: 4251) // Member w/o DLL spec (mutex_ type).
+#endif
+
 class BOOST_CONTRACT_DETAIL_DECLSPEC check_guard :
     private boost::noncopyable // Non-copyable resource (might use mutex, etc.).
 {
@@ -31,6 +36,10 @@ private:
     #endif
 };
 
+#ifdef BOOST_MSVC
+    #pragma warning(pop)
+#endif
+
 } } } // namespace
 
 /** @cond Needed because this header included by other public headers. */
diff --git a/include/boost/contract/detail/inlined/core/exception.hpp b/include/boost/contract/detail/inlined/core/exception.hpp
index 1969bb7..c123fc3 100644
--- a/include/boost/contract/detail/inlined/core/exception.hpp
+++ b/include/boost/contract/detail/inlined/core/exception.hpp
@@ -46,7 +46,7 @@
 
 namespace boost { namespace contract {
 
-exception::~exception() {}
+exception::~exception() BOOST_NOEXCEPT_OR_NOTHROW {}
 
 bad_virtual_result_cast::bad_virtual_result_cast(char const* from_type_name,
             char const* to_type_name) {
@@ -59,7 +59,7 @@ bad_virtual_result_cast::bad_virtual_result_cast(char const* from_type_name,
     what_ = text.str();
 }
 
-bad_virtual_result_cast::~bad_virtual_result_cast() {}
+bad_virtual_result_cast::~bad_virtual_result_cast() BOOST_NOEXCEPT_OR_NOTHROW {}
 
 char const* bad_virtual_result_cast::what() const BOOST_NOEXCEPT_OR_NOTHROW {
     return what_.c_str();
@@ -74,7 +74,7 @@ assertion_failure::assertion_failure(char const* const code) :
     file_(""), line_(0), code_(code)
 { init(); }
 
-assertion_failure::~assertion_failure() {}
+assertion_failure::~assertion_failure() BOOST_NOEXCEPT_OR_NOTHROW {}
 
 char const* assertion_failure::what() const BOOST_NOEXCEPT_OR_NOTHROW {
     return what_.c_str();
diff --git a/test/Jamfile.v2 b/test/Jamfile.v2
index 117d09f..8249dd6 100644
--- a/test/Jamfile.v2
+++ b/test/Jamfile.v2
@@ -260,11 +260,6 @@ test-suite specify
     [ subdir-compile-fail specify : post_pre_error ]
 ;
 
-test-suite misc
-:
-    [ subdir-run-with-no misc : mutex ]
-;
-
 test-suite call_if
 :
     [ subdir-run call_if : true_ ]
diff --git a/test/call_if/check_if.cpp b/test/call_if/check_if.cpp
index 27f4736..9420265 100644
--- a/test/call_if/check_if.cpp
+++ b/test/call_if/check_if.cpp
@@ -18,11 +18,12 @@ void push_back(std::vector<T>& vect, T const& val) {
     boost::contract::guard c = boost::contract::function()
         .postcondition([&] {
             BOOST_CONTRACT_ASSERT(
-                boost::contract::call_if<boost::has_equal_to<T> >(
+                boost::contract::check_if<boost::has_equal_to<T> >(
                     boost::bind(std::equal_to<T>(), boost::cref(vect.back()),
                             boost::cref(val))
-                ).else_([] { ++equal_skips; return true; })
+                )
             );
+            if(!boost::has_equal_to<T>::value) ++equal_skips;
         })
     ;
     vect.push_back(val);
@@ -38,7 +39,7 @@ int main() {
     std::vector<int> vi;
     equal_skips = 0;
     push_back(vi, 123);
-    BOOST_TEST_EQ(equal_skips, 0);
+    BOOST_TEST_EQ(equal_skips, 0u);
         
     unsigned const cnt =
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
diff --git a/test/constructor/contracts.cpp b/test/constructor/contracts.cpp
index e3cb2f5..74503d8 100644
--- a/test/constructor/contracts.cpp
+++ b/test/constructor/contracts.cpp
@@ -349,77 +349,77 @@ int main() {
     #endif
 
     BOOST_TEST_EQ(a::x_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::x_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::x_type::ctors(), a::x_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(c::y_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::y_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::y_type::ctors(), c::y_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(t<'d'>::z_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'d'>::z_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'d'>::z_type::ctors(), t<'d'>::z_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(t<'p'>::z_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'p'>::z_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'p'>::z_type::ctors(), t<'p'>::z_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(t<'q'>::z_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'q'>::z_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'q'>::z_type::ctors(), t<'q'>::z_type::dtors()); // No leak.
 
     BOOST_TEST_EQ(t<'e'>::z_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::z_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::z_type::ctors(), t<'e'>::z_type::dtors()); // No leak.
 
     // Following destroy only copies (actual objects are static data members).
 
     BOOST_TEST_EQ(a::n_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::n_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::n_type::copies(), a::n_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(c::m_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::m_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::m_type::copies(), c::m_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(t<'d'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'d'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::copies(), t<'e'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'p'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'p'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::copies(), t<'e'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'q'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'q'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::copies(), t<'e'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'e'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::copies(), t<'e'>::l_type::dtors()); // No leak
 
     #undef BOOST_CONTRACT_TEST_post
diff --git a/test/constructor/decl_entry_static_inv_all.cpp b/test/constructor/decl_entry_static_inv_all.cpp
index 6865050..6b46928 100644
--- a/test/constructor/decl_entry_static_inv_all.cpp
+++ b/test/constructor/decl_entry_static_inv_all.cpp
@@ -12,7 +12,7 @@
 #include <string>
 
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
diff --git a/test/constructor/decl_entry_static_inv_ends.cpp b/test/constructor/decl_entry_static_inv_ends.cpp
index 3c78cff..b919e2a 100644
--- a/test/constructor/decl_entry_static_inv_ends.cpp
+++ b/test/constructor/decl_entry_static_inv_ends.cpp
@@ -12,7 +12,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
diff --git a/test/constructor/decl_entry_static_inv_mid.cpp b/test/constructor/decl_entry_static_inv_mid.cpp
index 5792da8..fe791cd 100644
--- a/test/constructor/decl_entry_static_inv_mid.cpp
+++ b/test/constructor/decl_entry_static_inv_mid.cpp
@@ -12,7 +12,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
diff --git a/test/constructor/decl_exit_inv_all.cpp b/test/constructor/decl_exit_inv_all.cpp
index 8a1405a..92b4f74 100644
--- a/test/constructor/decl_exit_inv_all.cpp
+++ b/test/constructor/decl_exit_inv_all.cpp
@@ -11,7 +11,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -76,7 +76,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "a::ctor::post" << std::endl
         #endif
diff --git a/test/constructor/decl_exit_inv_ends.cpp b/test/constructor/decl_exit_inv_ends.cpp
index 655e9b1..2d0b334 100644
--- a/test/constructor/decl_exit_inv_ends.cpp
+++ b/test/constructor/decl_exit_inv_ends.cpp
@@ -11,7 +11,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -76,7 +76,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "a::ctor::post" << std::endl
         #endif
diff --git a/test/constructor/decl_exit_inv_mid.cpp b/test/constructor/decl_exit_inv_mid.cpp
index ecabd51..2e3d36f 100644
--- a/test/constructor/decl_exit_inv_mid.cpp
+++ b/test/constructor/decl_exit_inv_mid.cpp
@@ -11,7 +11,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -76,7 +76,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "a::ctor::post" << std::endl
         #endif
diff --git a/test/constructor/decl_exit_static_inv_all.cpp b/test/constructor/decl_exit_static_inv_all.cpp
index 8712df0..de618b5 100644
--- a/test/constructor/decl_exit_static_inv_all.cpp
+++ b/test/constructor/decl_exit_static_inv_all.cpp
@@ -12,7 +12,7 @@
 #include <string>
 
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -80,7 +80,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
             << "a::inv" << std::endl
         #endif
diff --git a/test/constructor/decl_exit_static_inv_ends.cpp b/test/constructor/decl_exit_static_inv_ends.cpp
index 724a050..6dd67ec 100644
--- a/test/constructor/decl_exit_static_inv_ends.cpp
+++ b/test/constructor/decl_exit_static_inv_ends.cpp
@@ -12,7 +12,7 @@
 #include <string>
 
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -74,7 +74,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
             << "a::inv" << std::endl
         #endif
diff --git a/test/constructor/decl_exit_static_inv_mid.cpp b/test/constructor/decl_exit_static_inv_mid.cpp
index 91278bd..6bfafb0 100644
--- a/test/constructor/decl_exit_static_inv_mid.cpp
+++ b/test/constructor/decl_exit_static_inv_mid.cpp
@@ -12,7 +12,7 @@
 #include <string>
             
 std::string ok_c() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "a::ctor::pre" << std::endl
             << "b::ctor::pre" << std::endl
@@ -70,7 +70,7 @@ std::string ok_a() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
             << "a::inv" << std::endl
         #endif
diff --git a/test/destructor/contracts.cpp b/test/destructor/contracts.cpp
index 7b070ea..3480c91 100644
--- a/test/destructor/contracts.cpp
+++ b/test/destructor/contracts.cpp
@@ -268,39 +268,39 @@ int main() {
     // Followings destroy only copies (actual objects are static data members).
 
     BOOST_TEST_EQ(a::n_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::n_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(a::n_type::copies(), a::n_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(c::m_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::m_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(c::m_type::copies(), c::m_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(t<'d'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'d'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'d'>::l_type::copies(), t<'d'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'p'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'p'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'p'>::l_type::copies(), t<'p'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'q'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'q'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'q'>::l_type::copies(), t<'q'>::l_type::dtors()); // No leak
     
     BOOST_TEST_EQ(t<'e'>::l_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(t<'e'>::l_type::copies(), t<'e'>::l_type::dtors()); // No leak
 
     #undef BOOST_CONTRACT_TEST_post
diff --git a/test/destructor/decl_entry_inv_all.cpp b/test/destructor/decl_entry_inv_all.cpp
index 720c808..1d9998f 100644
--- a/test/destructor/decl_entry_inv_all.cpp
+++ b/test/destructor/decl_entry_inv_all.cpp
@@ -11,7 +11,7 @@
 #include <string>
         
 std::string ok_a(bool failed = false) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "a::static_inv" << std::endl
             << "a::inv" << std::endl // This can fail.
@@ -35,7 +35,7 @@ std::string ok_a(bool failed = false) {
 enum checked { passed, failed, threw };
 
 std::string ok_b(checked check = passed) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "b::static_inv" << std::endl
             << "b::inv" << std::endl // This can fail.
@@ -58,7 +58,7 @@ std::string ok_b(checked check = passed) {
 }
 
 std::string ok_c(checked check = passed) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "c::static_inv" << std::endl
             << "c::inv" << std::endl // This can fail.
diff --git a/test/destructor/decl_entry_inv_ends.cpp b/test/destructor/decl_entry_inv_ends.cpp
index cac7c1e..baa28ca 100644
--- a/test/destructor/decl_entry_inv_ends.cpp
+++ b/test/destructor/decl_entry_inv_ends.cpp
@@ -11,7 +11,7 @@
 #include <string> 
 
 std::string ok_a(bool failed = false) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "a::static_inv" << std::endl
             << "a::inv" << std::endl // This can fail.
@@ -33,7 +33,7 @@ std::string ok_a(bool failed = false) {
 }
 
 std::string ok_b(bool threw = false) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "b::static_inv" << std::endl
         #endif
@@ -55,7 +55,7 @@ std::string ok_b(bool threw = false) {
 enum checked { passed, failed, threw };
         
 std::string ok_c(checked check = passed) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "c::static_inv" << std::endl
             << "c::inv" << std::endl // This can fail.
diff --git a/test/destructor/decl_entry_inv_mid.cpp b/test/destructor/decl_entry_inv_mid.cpp
index ab98d69..25b8aa1 100644
--- a/test/destructor/decl_entry_inv_mid.cpp
+++ b/test/destructor/decl_entry_inv_mid.cpp
@@ -30,7 +30,7 @@ std::string ok_a() {
 }
 
 std::string ok_b(bool failed = false) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "b::static_inv" << std::endl
             << "b::inv" << std::endl // This can fail.
@@ -126,7 +126,7 @@ int main() {
             ok.str(""); ok
                 << ok_a()
                 // Test entry b::inv failed...
-                << ok_b(BOOST_CONTRACT_TEST_entry_inv)
+                << ok_b(bool(BOOST_CONTRACT_TEST_entry_inv))
             ;
             out.str("");
         }
@@ -135,7 +135,7 @@ int main() {
             } catch(err const&) {
         #endif
         ok // ...then exec other dtors and check inv on throw (as dtor threw).
-            << ok_c(BOOST_CONTRACT_TEST_entry_inv)
+            << ok_c(bool(BOOST_CONTRACT_TEST_entry_inv))
         ;
         BOOST_TEST(out.eq(ok.str()));
     } catch(...) { BOOST_TEST(false); }
@@ -173,7 +173,7 @@ int main() {
         << ok_a() // Test no entry a::inv so no failure here.
         
         // Test entry b::inv failed (as all did).
-        << ok_b(BOOST_CONTRACT_TEST_entry_inv)
+        << ok_b(bool(BOOST_CONTRACT_TEST_entry_inv))
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "b::dtor::body" << std::endl
         #endif
diff --git a/test/function/contracts.cpp b/test/function/contracts.cpp
index b15e6a7..1531a0d 100644
--- a/test/function/contracts.cpp
+++ b/test/function/contracts.cpp
@@ -81,15 +81,15 @@ int main() {
     #endif
 
     BOOST_TEST_EQ(x_type::copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(x_type::evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(x_type::ctors(), x_type::dtors()); // No leak.
     
     BOOST_TEST_EQ(y_type::copies(),
-        BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+        BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(y_type::evals(),
-        BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+        BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(y_type::ctors(), y_type::dtors()); // No leak.
 
     #undef BOOST_CONTRACT_TEST_post
diff --git a/test/function/decl_pre_all.cpp b/test/function/decl_pre_all.cpp
index 1da790a..232b55c 100644
--- a/test/function/decl_pre_all.cpp
+++ b/test/function/decl_pre_all.cpp
@@ -9,7 +9,7 @@
 #include <string>
 
 std::string ok_f(bool failed = false) {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
             << "f::pre" << std::endl // Test no failure here.
         #endif
diff --git a/test/function/old_throw.cpp b/test/function/old_throw.cpp
index 9d87d7e..cada567 100644
--- a/test/function/old_throw.cpp
+++ b/test/function/old_throw.cpp
@@ -36,7 +36,7 @@ int main() {
             BOOST_TEST(false);
         #endif
     } catch(err const&) {
-        ok.str(""); ok
+        ok.str(""); ok << "" // Suppress a warning.
             #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
                 << "f::pre" << std::endl
             #endif
diff --git a/test/misc/mutex.cpp b/test/misc/mutex.cpp
deleted file mode 100644
index 32d8b67..0000000
--- a/test/misc/mutex.cpp
+++ /dev/null
@@ -1,258 +0,0 @@
-
-// Test scoped mutex locks before contracts (no need to also test ctors, etc.).
-
-#include "../detail/oteststream.hpp"
-#include <boost/contract.hpp>
-#include <boost/thread/mutex.hpp>
-#include <boost/thread/thread.hpp>
-#include <boost/detail/lightweight_test.hpp>
-#include <sstream>
-
-boost::contract::test::detail::oteststream out;
-
-struct b : private boost::contract::constructor_precondition<b> {
-    static void static_invariant() { out << "b::static_inv" << std::endl; }
-    void invariant() const { out << "b::inv" << std::endl; }
-    
-    b() : boost::contract::constructor_precondition<b>(
-            [&] { out << "b::ctor::pre" << std::endl; }) {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::constructor(this)
-            .old([&] { out << "b::ctor::old" << std::endl; })
-            .postcondition([&] { out << "b::ctor::post" << std::endl; })
-        ;
-        out << "b::ctor::body" << std::endl;
-    }
-
-    virtual ~b() {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::destructor(this)
-            .old([&] { out << "b::dtor::old" << std::endl; })
-            .postcondition([&] { out << "b::dtor::post" << std::endl; })
-        ;
-        out << "b::dtor::body" << std::endl;
-    }
-
-    virtual void f(boost::contract::virtual_* v = 0) const {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::public_function(v, this)
-            .precondition([&] { out << "b::f::pre" << std::endl; })
-            .old([&] { out << "b::f::old" << std::endl; })
-            .postcondition([&] { out << "b::f::post" << std::endl; })
-        ;
-        out << "b::f::body" << std::endl;
-    }
-    
-    virtual void g(boost::contract::virtual_* v = 0) const {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::public_function(v, this)
-            .precondition([&] { out << "b::g::pre" << std::endl; })
-            .old([&] { out << "b::g::old" << std::endl; })
-            .postcondition([&] { out << "b::g::post" << std::endl; })
-        ;
-        out << "b::g::body" << std::endl;
-    }
-
-private:
-    mutable boost::mutex mutex_;
-};
-
-struct a
-    #define BASES private boost::contract::constructor_precondition<a>, public b
-    : BASES
-{
-    typedef BOOST_CONTRACT_BASE_TYPES(BASES) base_types;
-    #undef BASES
-
-    static void static_invariant() { out << "a::static_inv" << std::endl; }
-    void invariant() const { out << "a::inv" << std::endl; }
-
-    a() : boost::contract::constructor_precondition<a>(
-            [&] { out << "a::ctor::pre" << std::endl; }) {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::constructor(this)
-            .old([&] { out << "a::ctor::old" << std::endl; })
-            .postcondition([&] { out << "a::ctor::post" << std::endl; })
-        ;
-        out << "a::ctor::body" << std::endl;
-    }
-    
-    ~a() {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::destructor(this)
-            .old([&] { out << "a::dtor::old" << std::endl; })
-            .postcondition([&] { out << "a::dtor::post" << std::endl; })
-        ;
-        out << "a::dtor::body" << std::endl;
-    }
-    
-    void f(boost::contract::virtual_* v = 0) const /* override */ {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::public_function<override_f>(
-                v, &a::f, this)
-            .precondition([&] { out << "a::f::pre" << std::endl; })
-            .old([&] { out << "a::f::old" << std::endl; })
-            .postcondition([&] { out << "a::f::post" << std::endl; })
-        ;
-        out << "a::f::body" << std::endl;
-    }
-    BOOST_CONTRACT_OVERRIDE(f)
-    
-    void g(boost::contract::virtual_* v = 0) const /* override */ {
-        boost::mutex::scoped_lock lock(mutex_);
-        boost::contract::guard c = boost::contract::public_function<override_g>(
-                v, &a::g, this)
-            .precondition([&] { out << "a::g::pre" << std::endl; })
-            .old([&] { out << "a::g::old" << std::endl; })
-            .postcondition([&] { out << "a::g::post" << std::endl; })
-        ;
-        out << "a::g::body" << std::endl;
-    }
-    BOOST_CONTRACT_OVERRIDE(g)
-
-private:
-    mutable boost::mutex mutex_;
-};
-
-int main() {
-    // Unfortunately, I cannot compile Boost.Thread on Cygwin with GCC and
-    // CLang... I get linker errors even if I use `threadapi=pthread` and add
-    // `<library>/boost/thread//boost_thread` to the Jamfile.
-#ifdef BOOST_MSVC
-    {
-        a aa;
-        boost::thread tf([&aa] { aa.f(); });
-        boost::thread tg([&aa] { aa.g(); });
-        tf.join();
-        tg.join();
-    }
-
-    std::ostringstream ok; ok // Mutexes also guarantee order of text in `out`.
-        // Test constructor.
-        
-        #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
-            << "a::ctor::pre" << std::endl
-            << "b::ctor::pre" << std::endl
-        #endif
-
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "b::static_inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::ctor::old" << std::endl
-        #endif
-        << "b::ctor::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::ctor::post" << std::endl
-        #endif
-        
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "a::static_inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "a::ctor::old" << std::endl
-        #endif
-        << "a::ctor::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "a::ctor::post" << std::endl
-        #endif
-
-        // Test public functions.
-
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
-            << "b::f::pre" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::f::old" << std::endl
-            << "a::f::old" << std::endl
-        #endif
-        << "a::f::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::f::old" << std::endl
-            << "b::f::post" << std::endl
-            << "a::f::post" << std::endl
-        #endif
-
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_PRECONDITIONS
-            << "b::g::pre" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::g::old" << std::endl
-            << "a::g::old" << std::endl
-        #endif
-        << "a::g::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::g::old" << std::endl
-            << "b::g::post" << std::endl
-            << "a::g::post" << std::endl
-        #endif
-
-        // Test destructor.
-
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "a::static_inv" << std::endl
-            << "a::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "a::dtor::old" << std::endl
-        #endif
-        << "a::dtor::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "a::static_inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "a::dtor::post" << std::endl
-        #endif
-
-        #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
-            << "b::static_inv" << std::endl
-            << "b::inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::dtor::old" << std::endl
-        #endif
-        << "b::dtor::body" << std::endl
-        #ifndef BOOST_CONTRACT_NO_EXIT_INVARIANTS
-            << "b::static_inv" << std::endl
-        #endif
-        #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
-            << "b::dtor::post" << std::endl
-        #endif
-    ;
-    BOOST_TEST(out.eq(ok.str()));
-#endif
-    return boost::report_errors();
-}
-
diff --git a/test/old/noncopyable.cpp b/test/old/noncopyable.cpp
index 92b520f..6a8a7dc 100644
--- a/test/old/noncopyable.cpp
+++ b/test/old/noncopyable.cpp
@@ -121,7 +121,7 @@ int main() {
 
     old_checks = 0;
     next(n);
-    BOOST_TEST_EQ(old_checks, 0);
+    BOOST_TEST_EQ(old_checks, 0u);
 
     // Test virtual functions (old values with `v`).
     
@@ -146,7 +146,7 @@ int main() {
     a<ncp> an;
     old_checks = 0;
     an.next(n);
-    BOOST_TEST_EQ(old_checks, 0);
+    BOOST_TEST_EQ(old_checks, 0u);
 
     return boost::report_errors();
 }
diff --git a/test/public_function/contracts.cpp b/test/public_function/contracts.cpp
index 571f216..2e8f33c 100644
--- a/test/public_function/contracts.cpp
+++ b/test/public_function/contracts.cpp
@@ -70,37 +70,37 @@ int main() {
     BOOST_TEST_EQ(r.value, "A");
     BOOST_TEST_EQ(s.value, "acde");
     BOOST_TEST_EQ(s.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4u, 0u));
     BOOST_TEST_EQ(s.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4u, 0u));
     BOOST_TEST_EQ(s.ctors(), s.dtors() + 1); // 1 for local var.
 
     BOOST_TEST_EQ(aa.x.value, "aA");
     BOOST_TEST_EQ(aa.x.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.x.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.x.ctors(), aa.x.dtors() + 1); // 1 for member var.
 
     BOOST_TEST_EQ(aa.y.value, "cA");
     BOOST_TEST_EQ(aa.y.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.y.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.y.ctors(), aa.y.dtors() + 1); // 1 for member var.
     
     BOOST_TEST_EQ(aa.t<'d'>::z.value, "dA");
     BOOST_TEST_EQ(aa.t<'d'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.t<'d'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.t<'d'>::z.ctors(), aa.t<'d'>::z.dtors() + 1); // 1 member.
 
     BOOST_TEST_EQ(aa.t<'e'>::z.value, "eA");
     BOOST_TEST_EQ(aa.t<'e'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.t<'e'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.t<'e'>::z.ctors(), aa.t<'e'>::z.dtors() + 1); // 1 member.
 
     #undef BOOST_CONTRACT_TEST_post
diff --git a/test/public_function/contracts.hpp b/test/public_function/contracts.hpp
index 3df0162..2c40970 100644
--- a/test/public_function/contracts.hpp
+++ b/test/public_function/contracts.hpp
@@ -151,7 +151,8 @@ struct b {
 
     virtual ~b() {}
 
-    virtual result_type& f(s_type& s) { // No contract.
+    // No contract (no virtual_ so this is not actually overridden by a::f).
+    virtual result_type& f(s_type& s) {
         static result_type result("none-b");
         out << "b::f::body" << std::endl;
         result.value = s.value;
diff --git a/test/public_function/decl_exit_inv_all.cpp b/test/public_function/decl_exit_inv_all.cpp
index f19de5a..00cee36 100644
--- a/test/public_function/decl_exit_inv_all.cpp
+++ b/test/public_function/decl_exit_inv_all.cpp
@@ -35,7 +35,7 @@ std::string ok_begin() {
 }
         
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_exit_inv_ends.cpp b/test/public_function/decl_exit_inv_ends.cpp
index c293a1f..4982328 100644
--- a/test/public_function/decl_exit_inv_ends.cpp
+++ b/test/public_function/decl_exit_inv_ends.cpp
@@ -34,7 +34,7 @@ std::string ok_begin() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_exit_inv_mid.cpp b/test/public_function/decl_exit_inv_mid.cpp
index fe382da..ecadc28 100644
--- a/test/public_function/decl_exit_inv_mid.cpp
+++ b/test/public_function/decl_exit_inv_mid.cpp
@@ -33,7 +33,7 @@ std::string ok_begin() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_exit_inv_none.cpp b/test/public_function/decl_exit_inv_none.cpp
index 2e8d313..de92935 100644
--- a/test/public_function/decl_exit_inv_none.cpp
+++ b/test/public_function/decl_exit_inv_none.cpp
@@ -74,6 +74,7 @@ int main() {
     
     a_exit_inv = true;
     b_exit_inv = false;
+    a_entering_inv = b_entering_inv = c_entering_inv =
             BOOST_PP_IIF(BOOST_CONTRACT_TEST_entry_inv, true, false);
     out.str("");
     aa.f();
diff --git a/test/public_function/decl_exit_static_inv_all.cpp b/test/public_function/decl_exit_static_inv_all.cpp
index b0d2720..1b4df70 100644
--- a/test/public_function/decl_exit_static_inv_all.cpp
+++ b/test/public_function/decl_exit_static_inv_all.cpp
@@ -35,7 +35,7 @@ std::string ok_begin() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_exit_static_inv_ends.cpp b/test/public_function/decl_exit_static_inv_ends.cpp
index 87a0818..7dea82a 100644
--- a/test/public_function/decl_exit_static_inv_ends.cpp
+++ b/test/public_function/decl_exit_static_inv_ends.cpp
@@ -34,7 +34,7 @@ std::string ok_begin() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_exit_static_inv_mid.cpp b/test/public_function/decl_exit_static_inv_mid.cpp
index 822c786..a3326ae 100644
--- a/test/public_function/decl_exit_static_inv_mid.cpp
+++ b/test/public_function/decl_exit_static_inv_mid.cpp
@@ -33,7 +33,7 @@ std::string ok_begin() {
 }
 
 std::string ok_end() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_POSTCONDITIONS
             << "c::f::old" << std::endl
             << "c::f::post" << std::endl
diff --git a/test/public_function/decl_pre_all.cpp b/test/public_function/decl_pre_all.cpp
index 7c878a6..5735833 100644
--- a/test/public_function/decl_pre_all.cpp
+++ b/test/public_function/decl_pre_all.cpp
@@ -11,7 +11,7 @@
 #include <string>
 
 std::string ok_begin() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "c::static_inv" << std::endl
             << "c::inv" << std::endl
diff --git a/test/public_function/decl_pre_ends.cpp b/test/public_function/decl_pre_ends.cpp
index faf99ef..cfea274 100644
--- a/test/public_function/decl_pre_ends.cpp
+++ b/test/public_function/decl_pre_ends.cpp
@@ -11,7 +11,7 @@
 #include <string>
         
 std::string ok_begin() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "c::static_inv" << std::endl
             << "c::inv" << std::endl
diff --git a/test/public_function/decl_pre_mid.cpp b/test/public_function/decl_pre_mid.cpp
index aa33279..dfcb6f7 100644
--- a/test/public_function/decl_pre_mid.cpp
+++ b/test/public_function/decl_pre_mid.cpp
@@ -11,7 +11,7 @@
 #include <string>
 
 std::string ok_begin() {
-    std::ostringstream ok; ok
+    std::ostringstream ok; ok << "" // Suppress a warning.
         #ifndef BOOST_CONTRACT_NO_ENTRY_INVARIANTS
             << "c::static_inv" << std::endl
             << "c::inv" << std::endl
diff --git a/test/public_function/protected.cpp b/test/public_function/protected.cpp
index c2ac7b9..54427b5 100644
--- a/test/public_function/protected.cpp
+++ b/test/public_function/protected.cpp
@@ -11,15 +11,16 @@
 
 boost::contract::test::detail::oteststream out;
 
-// NOTE: This is the correct way of programming contracts for base protected
-// and public overriding function.
-
 struct b {
     static void static_invariant() { out << "b::static_inv" << std::endl; }
     void invariant() const { out << "b::inv" << std::endl; }
 
 protected:
-    virtual void f() { // Protected do not use public_function (or virtual_).
+    // NOTE: This is the correct way of programming contracts for overridden
+    // protected and overriding public functions: Both must use virtual_
+    // (otherwise C++ won't override because mismatching parameters), but
+    // overridden protected does not use public_function.
+    virtual void f(boost::contract::virtual_* v = 0) {
         boost::contract::guard c = boost::contract::function()
             .precondition([] { out << "b::f::pre" << std::endl; })
             .old([] { out << "b::f::old" << std::endl; })
diff --git a/test/public_function/virtual.cpp b/test/public_function/virtual.cpp
index 10752b9..2915d0e 100644
--- a/test/public_function/virtual.cpp
+++ b/test/public_function/virtual.cpp
@@ -71,38 +71,38 @@ int main() {
     BOOST_TEST_EQ(r.value, "A");
     BOOST_TEST_EQ(s.value, "acde");
     BOOST_TEST_EQ(s.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4u, 0u));
     BOOST_TEST_EQ(s.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 4u, 0u));
     BOOST_TEST_EQ(s.ctors(), s.dtors() + 1); // 1 local var.
 
     // Cannot access x via ca, but only via aa.
     BOOST_TEST_EQ(aa.x.value, "aA");
     BOOST_TEST_EQ(aa.x.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.x.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(aa.x.ctors(), aa.x.dtors() + 1); // 1 data member.
 
     BOOST_TEST_EQ(ca.y.value, "cA");
     BOOST_TEST_EQ(ca.y.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.y.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.y.ctors(), ca.y.dtors() + 1); // 1 data member.
     
     BOOST_TEST_EQ(ca.t<'d'>::z.value, "dA");
     BOOST_TEST_EQ(ca.t<'d'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.t<'d'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.t<'d'>::z.ctors(), ca.t<'d'>::z.dtors() + 1); // 1 member.
 
     BOOST_TEST_EQ(ca.t<'e'>::z.value, "eA");
     BOOST_TEST_EQ(ca.t<'e'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.t<'e'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(ca.t<'e'>::z.ctors(), ca.t<'e'>::z.dtors() + 1); // 1 member.
 
     #undef BOOST_CONTRACT_TEST_post
diff --git a/test/public_function/virtual_branch.cpp b/test/public_function/virtual_branch.cpp
index c41bf4f..e0baa3b 100644
--- a/test/public_function/virtual_branch.cpp
+++ b/test/public_function/virtual_branch.cpp
@@ -61,30 +61,30 @@ int main() {
     BOOST_TEST_EQ(r.value, "C");
     BOOST_TEST_EQ(s.value, "cde");
     BOOST_TEST_EQ(s.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 3, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 3u, 0u));
     BOOST_TEST_EQ(s.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 3, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 3u, 0u));
     BOOST_TEST_EQ(s.ctors(), s.dtors() + 1); // 1 local var.
 
     BOOST_TEST_EQ(cc.y.value, "cC");
     BOOST_TEST_EQ(cc.y.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.y.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.y.ctors(), cc.y.dtors() + 1); // 1 data member.
     
     BOOST_TEST_EQ(cc.t<'d'>::z.value, "dC");
     BOOST_TEST_EQ(cc.t<'d'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.t<'d'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.t<'d'>::z.ctors(), cc.t<'d'>::z.dtors() + 1); // 1 member.
 
     BOOST_TEST_EQ(cc.t<'e'>::z.value, "eC");
     BOOST_TEST_EQ(cc.t<'e'>::z.copies(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.t<'e'>::z.evals(),
-            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1, 0));
+            BOOST_PP_IIF(BOOST_CONTRACT_TEST_post, 1u, 0u));
     BOOST_TEST_EQ(cc.t<'e'>::z.ctors(), cc.t<'e'>::z.dtors() + 1); // 1 member.
 
     return boost::report_errors();