diff --git a/.travis.yml b/.travis.yml
index 2131229f6..8713d9e16 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -97,6 +97,14 @@ matrix:
     ##########################################################################
     # Build with variations in the configuration
     ##########################################################################
+    # With C++17 instead of C++14, on Clang
+    - env: UNIT_TESTS=true COMPILER=default BOOST_VERSION=default CMAKE_OPTIONS="-DBOOST_HANA_ENABLE_CPP17=ON"
+      addons: *defaults
+
+    # With C++17 instead of C++14, on GCC
+    - env: UNIT_TESTS=true COMPILER=g++-6     BOOST_VERSION=default CMAKE_OPTIONS="-DBOOST_HANA_ENABLE_CPP17=ON"
+      addons: { apt: { packages: ["g++-6", "valgrind"], sources: ["ubuntu-toolchain-r-test"] } }
+
     # Without concept checks
     - env: UNIT_TESTS=true COMPILER=default BOOST_VERSION=default CMAKE_OPTIONS="-DBOOST_HANA_ENABLE_CONCEPT_CHECKS=OFF"
       addons: *defaults
diff --git a/CMakeLists.txt b/CMakeLists.txt
index d20d07619..28dd29cbb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -5,6 +5,22 @@
 cmake_minimum_required(VERSION 3.8)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")
 
+##############################################################################
+# Setup CMake options
+##############################################################################
+option(BOOST_HANA_ENABLE_CONCEPT_CHECKS "Enable concept checking in the interface methods." ON)
+option(BOOST_HANA_ENABLE_DEBUG_MODE "Enable Hana's debug mode." OFF)
+option(BOOST_HANA_ENABLE_CPP17 "Build with C++17 instead of usual required C++ standard. Useful for testing." OFF)
+
+option(BOOST_HANA_ENABLE_STRING_UDL
+"Enable the GNU extension allowing the special string literal operator\
+ template, which enables the _s suffix for creating compile-time strings." ON)
+
+option(BOOST_HANA_ENABLE_EXCEPTIONS
+"Build with exceptions enabled. Note that Hana does not make use of exceptions,\
+ but this switch can be disabled when building the tests to assess that it is\
+ really the case." ON)
+
 
 ##############################################################################
 # Setup project
@@ -31,14 +47,19 @@ include(CheckCxxCompilerSupport)
 # Setup the 'hana' header-only library target, along with its install target
 # and exports.
 ##############################################################################
+include(CheckCXXCompilerFlag)
 add_library(hana INTERFACE)
 target_include_directories(hana INTERFACE "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/include>"
                                           $<INSTALL_INTERFACE:include>)
 # With Clang on Windows, the -std=c++14 flag is incorrectly set and the compiler
-# complains about the unkown option. TODO: Remove this workaround once the
+# complains about the unknown option. TODO: Remove this workaround once the
 # underlying bug is fixed in CMake: https://gitlab.kitware.com/cmake/cmake/issues/17015
 if (NOT (MSVC AND ${CMAKE_CXX_COMPILER_ID} STREQUAL "Clang"))
-    target_compile_features(hana INTERFACE cxx_std_14)
+    if (BOOST_HANA_ENABLE_CPP17)
+        target_compile_features(hana INTERFACE cxx_std_17)
+    else()
+        target_compile_features(hana INTERFACE cxx_std_14)
+    endif()
 endif()
 
 # Export the `hana` library into a HanaConfig.cmake file
@@ -52,25 +73,8 @@ install(FILES "${CMAKE_CURRENT_BINARY_DIR}/hana.pc" DESTINATION lib/pkgconfig)
 
 
 ##############################################################################
-# Setup CMake options
-##############################################################################
-option(BOOST_HANA_ENABLE_CONCEPT_CHECKS "Enable concept checking in the interface methods." ON)
-option(BOOST_HANA_ENABLE_DEBUG_MODE "Enable Hana's debug mode." OFF)
-
-option(BOOST_HANA_ENABLE_STRING_UDL
-"Enable the GNU extension allowing the special string literal operator\
- template, which enables the _s suffix for creating compile-time strings." ON)
-
-option(BOOST_HANA_ENABLE_EXCEPTIONS
-"Build with exceptions enabled. Note that Hana does not make use of exceptions,\
- but this switch can be disabled when building the tests to assess that it is\
- really the case." ON)
-
-
-##############################################################################
 # Function to setup common compiler flags on tests and examples
 ##############################################################################
-include(CheckCXXCompilerFlag)
 function(boost_hana_set_test_properties target)
     target_link_libraries(${target} PRIVATE hana)
     set_target_properties(${target} PROPERTIES CXX_EXTENSIONS NO)
diff --git a/example/chain.cpp b/example/chain.cpp
index 04a3fe41e..0e7850b74 100644
--- a/example/chain.cpp
+++ b/example/chain.cpp
@@ -28,7 +28,7 @@ struct Person {
 };
 
 int main() {
-    Person john{30};
+    constexpr Person john{30};
 
     // Can't dereference a non-pointer.
     BOOST_HANA_CONSTANT_CHECK(f(john) == hana::nothing);
diff --git a/example/cppcon_2014/functor.cpp b/example/cppcon_2014/functor.cpp
index b447002ca..b616a5241 100644
--- a/example/cppcon_2014/functor.cpp
+++ b/example/cppcon_2014/functor.cpp
@@ -15,7 +15,7 @@ using namespace cppcon;
 int main() {
     // transform
     {
-        auto m = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto m = matrix(
             row(1,              hana::int_c<2>, 3),
             row(hana::int_c<4>, 5,              6),
             row(7,              8,              hana::int_c<9>)
diff --git a/example/cppcon_2014/matrix.cpp b/example/cppcon_2014/matrix.cpp
index 3143459c5..0d5d020f1 100644
--- a/example/cppcon_2014/matrix.cpp
+++ b/example/cppcon_2014/matrix.cpp
@@ -13,7 +13,7 @@ using namespace cppcon;
 int main() {
     // transpose
     {
-        auto m = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto m = matrix(
             row(1, 2.2, '3'),
             row(4, '5', 6)
         );
@@ -30,7 +30,7 @@ int main() {
 
     // vector
     {
-        auto v = vector(1, '2', hana::int_c<3>, 4.2f);
+        BOOST_HANA_CONSTEXPR_LAMBDA auto v = vector(1, '2', hana::int_c<3>, 4.2f);
         BOOST_HANA_CONSTEXPR_CHECK(v.size() == 4ul);
         BOOST_HANA_CONSTEXPR_CHECK(v.nrows() == 4ul);
         BOOST_HANA_CONSTEXPR_CHECK(v.ncolumns() == 1ul);
@@ -38,7 +38,7 @@ int main() {
 
     // matrix.at
     {
-        auto m = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto m = matrix(
             row(1, '2', 3),
             row('4', hana::char_c<'5'>, 6),
             row(hana::int_c<7>, '8', 9.3)
@@ -58,7 +58,7 @@ int main() {
 
     // size, ncolumns, nrows
     {
-        auto m = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto m = matrix(
             row(1, '2', 3),
             row('4', hana::char_c<'5'>, 6)
         );
diff --git a/example/cppcon_2014/ring.cpp b/example/cppcon_2014/ring.cpp
index 718539ccc..9d06400de 100644
--- a/example/cppcon_2014/ring.cpp
+++ b/example/cppcon_2014/ring.cpp
@@ -16,12 +16,12 @@ using namespace cppcon;
 int main() {
     // mult
     {
-        auto a = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto a = matrix(
             row(1, 2, 3),
             row(4, 5, 6)
         );
 
-        auto b = matrix(
+        BOOST_HANA_CONSTEXPR_LAMBDA auto b = matrix(
             row(1, 2),
             row(3, 4),
             row(5, 6)
diff --git a/example/functional/fix.cpp b/example/functional/fix.cpp
index 8547a8d1a..62ad03742 100644
--- a/example/functional/fix.cpp
+++ b/example/functional/fix.cpp
@@ -8,7 +8,7 @@
 namespace hana = boost::hana;
 
 
-BOOST_HANA_CONSTEXPR_LAMBDA auto factorial = hana::fix([](auto fact, auto n) -> int {
+BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA auto factorial = hana::fix([](auto fact, auto n) -> int {
     if (n == 0) return 1;
     else        return n * fact(n - 1);
 });
diff --git a/example/integral_constant.cpp b/example/integral_constant.cpp
index c6eef44e3..aaad126da 100644
--- a/example/integral_constant.cpp
+++ b/example/integral_constant.cpp
@@ -44,7 +44,7 @@ BOOST_HANA_RUNTIME_CHECK(s == "xxxxxyyyyyzzzzz");
 
 //! [times_higher_order]
 std::string s;
-BOOST_HANA_CONSTEXPR_LAMBDA auto functions = hana::make_tuple(
+auto functions = hana::make_tuple(
     [&] { s += "x"; },
     [&] { s += "y"; },
     [&] { s += "z"; }
diff --git a/example/monadic_fold_left.cpp b/example/monadic_fold_left.cpp
index 8a5373a3a..734c055e0 100644
--- a/example/monadic_fold_left.cpp
+++ b/example/monadic_fold_left.cpp
@@ -2,6 +2,7 @@
 // Distributed under the Boost Software License, Version 1.0.
 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
 
+#include <boost/hana/assert.hpp>
 #include <boost/hana/equal.hpp>
 #include <boost/hana/monadic_fold_left.hpp>
 #include <boost/hana/optional.hpp>
@@ -41,6 +42,12 @@ struct common_type<T1, Tn...>
 template <typename ...Ts>
 using common_type_t = typename common_type<Ts...>::type;
 
+BOOST_HANA_CONSTANT_CHECK(
+  builtin_common_t(hana::type_c<int>, hana::type_c<float>)
+    ==
+  hana::just(hana::type_c<float>)
+);
+
 static_assert(std::is_same<
     common_type_t<char, short, char, short>,
     int
diff --git a/example/optional/applicative.complex.cpp b/example/optional/applicative.complex.cpp
index 72dc9f012..f8eb84a73 100644
--- a/example/optional/applicative.complex.cpp
+++ b/example/optional/applicative.complex.cpp
@@ -39,6 +39,7 @@ BOOST_HANA_CONSTEXPR_LAMBDA auto evaluate = hana::ap(function<op>, digit<x>, dig
 
 int main() {
     BOOST_HANA_CONSTEXPR_CHECK(evaluate<'1', '+', '2'> == hana::just(1 + 2));
+    BOOST_HANA_CONSTEXPR_CHECK(evaluate<'4', '-', '2'> == hana::just(4 - 2));
 
     BOOST_HANA_CONSTANT_CHECK(evaluate<'?', '+', '2'> == hana::nothing);
     BOOST_HANA_CONSTANT_CHECK(evaluate<'1', '?', '2'> == hana::nothing);
diff --git a/example/optional/sfinae_friendly_metafunctions.cpp b/example/optional/sfinae_friendly_metafunctions.cpp
index 1db88f3be..392154b39 100644
--- a/example/optional/sfinae_friendly_metafunctions.cpp
+++ b/example/optional/sfinae_friendly_metafunctions.cpp
@@ -3,6 +3,7 @@
 // (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
 
 #include <boost/hana/assert.hpp>
+#include <boost/hana/equal.hpp>
 #include <boost/hana/not.hpp>
 #include <boost/hana/optional.hpp>
 #include <boost/hana/traits.hpp>
@@ -29,9 +30,15 @@ auto common_type_impl = hana::sfinae([](auto t, auto u) -> hana::type<
 > { return {}; });
 
 template <typename T, typename U>
-using common_type2 = decltype(common_type_impl(hana::type_c<T>, hana::type_c<U>));
+using common_type = decltype(common_type_impl(hana::type_c<T>, hana::type_c<U>));
 
-static_assert(!has_type<common_type2<int, int*>>{}, "");
-static_assert(std::is_same<common_type2<int, float>::type, float>{}, "");
+BOOST_HANA_CONSTANT_CHECK(
+  common_type_impl(hana::type_c<int>, hana::type_c<float>)
+    ==
+  hana::just(hana::type_c<float>)
+);
+
+static_assert(!has_type<common_type<int, int*>>{}, "");
+static_assert(std::is_same<common_type<int, float>::type, float>{}, "");
 
 int main() { }
diff --git a/include/boost/hana/assert.hpp b/include/boost/hana/assert.hpp
index e74691051..960310769 100644
--- a/include/boost/hana/assert.hpp
+++ b/include/boost/hana/assert.hpp
@@ -286,16 +286,35 @@ Distributed under the Boost Software License, Version 1.0.
 // BOOST_HANA_CONSTEXPR_CHECK and BOOST_HANA_CONSTEXPR_CHECK_MSG
 //////////////////////////////////////////////////////////////////////////////
 
-//! @ingroup group-assertions
-//! Equivalent to `BOOST_HANA_CONSTEXPR_ASSERT_MSG`, but not influenced by the
-//! `BOOST_HANA_CONFIG_DISABLE_ASSERTIONS` config macro. For internal use only.
+#if defined(BOOST_HANA_DOXYGEN_INVOKED)
+    //! @ingroup group-assertions
+    //! Equivalent to `BOOST_HANA_CONSTEXPR_ASSERT_MSG`, but not influenced by
+    //! the `BOOST_HANA_CONFIG_DISABLE_ASSERTIONS` config macro.
+    //! For internal use only.
+#   define BOOST_HANA_CONSTEXPR_CHECK_MSG(condition, message) implementation-defined
+
+    //! @ingroup group-assertions
+    //! Equivalent to `BOOST_HANA_CONSTEXPR_ASSERT`, but not influenced by the
+    //! `BOOST_HANA_CONFIG_DISABLE_ASSERTIONS` config macro.
+    //! For internal use only.
+#   define BOOST_HANA_CONSTEXPR_CHECK(...) implementation-defined
+
+#elif defined(BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA)
+
+#   define BOOST_HANA_CONSTEXPR_CHECK_MSG(condition, message)               \
+        static_assert(condition, message)                                   \
+/**/
+
+#   define BOOST_HANA_CONSTEXPR_CHECK(...)                                  \
+        static_assert((__VA_ARGS__), BOOST_HANA_PP_STRINGIZE(__VA_ARGS__))  \
+/**/
+
+#else
+
 #   define BOOST_HANA_CONSTEXPR_CHECK_MSG(condition, message)               \
         BOOST_HANA_RUNTIME_CHECK_MSG(condition, message)                    \
 /**/
 
-//! @ingroup group-assertions
-//! Equivalent to `BOOST_HANA_CONSTEXPR_ASSERT`, but not influenced by the
-//! `BOOST_HANA_CONFIG_DISABLE_ASSERTIONS` config macro. For internal use only.
 #   define BOOST_HANA_CONSTEXPR_CHECK(...)                                  \
         BOOST_HANA_CONSTEXPR_CHECK_MSG(                                     \
             (__VA_ARGS__),                                                  \
@@ -303,4 +322,6 @@ Distributed under the Boost Software License, Version 1.0.
         )                                                                   \
 /**/
 
+#endif
+
 #endif // !BOOST_HANA_ASSERT_HPP
diff --git a/include/boost/hana/cartesian_product.hpp b/include/boost/hana/cartesian_product.hpp
index eaf8bb4d9..556c3b523 100644
--- a/include/boost/hana/cartesian_product.hpp
+++ b/include/boost/hana/cartesian_product.hpp
@@ -49,7 +49,7 @@ BOOST_HANA_NAMESPACE_BEGIN
         template <std::size_t ...Lengths>
         struct cartesian_product_indices {
             static constexpr std::size_t total_length() {
-                std::size_t lengths[] = {Lengths...};
+                std::size_t lengths[sizeof...(Lengths)] = {Lengths...};
                 std::size_t r = 1;
                 for (std::size_t len: lengths)
                     r *= len;
@@ -59,7 +59,7 @@ BOOST_HANA_NAMESPACE_BEGIN
             static constexpr std::size_t length = total_length();
 
             static constexpr auto indices_of(std::size_t i) {
-                constexpr std::size_t lengths[] = {Lengths...};
+                constexpr std::size_t lengths[sizeof...(Lengths)] = {Lengths...};
                 constexpr std::size_t n = sizeof...(Lengths);
                 detail::array<std::size_t, n> result{};
                 for (std::size_t j = n; j--;) {
diff --git a/include/boost/hana/config.hpp b/include/boost/hana/config.hpp
index 6cf6ace71..bf70920b4 100644
--- a/include/boost/hana/config.hpp
+++ b/include/boost/hana/config.hpp
@@ -124,14 +124,21 @@ Distributed under the Boost Software License, Version 1.0.
 // Caveats and other compiler-dependent options
 //////////////////////////////////////////////////////////////////////////////
 
-// BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA enables some constructs requiring
-// `constexpr` lambdas, which are not in the language (yet).
-// Currently always disabled.
+// `BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA` enables some constructs requiring
+// `constexpr` lambdas, which are in the language starting with C++17.
 //
-// BOOST_HANA_CONSTEXPR_LAMBDA expands to `constexpr` if constexpr lambdas
+// Always disabled for now because Clang only has partial support for them
+// (captureless lambdas only).
+#if defined(__cplusplus) && __cplusplus > 201402L
+#   define BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA constexpr
+// #   define BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA
+#else
+#   define BOOST_HANA_CONSTEXPR_STATELESS_LAMBDA /* nothing */
+#endif
+
+// `BOOST_HANA_CONSTEXPR_LAMBDA` expands to `constexpr` if constexpr lambdas
 // are supported and to nothing otherwise.
-#if 0
-#   define BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA
+#if defined(BOOST_HANA_CONFIG_HAS_CONSTEXPR_LAMBDA)
 #   define BOOST_HANA_CONSTEXPR_LAMBDA constexpr
 #else
 #   define BOOST_HANA_CONSTEXPR_LAMBDA /* nothing */
diff --git a/include/boost/hana/detail/unpack_flatten.hpp b/include/boost/hana/detail/unpack_flatten.hpp
index 0c65e803b..65cb3d950 100644
--- a/include/boost/hana/detail/unpack_flatten.hpp
+++ b/include/boost/hana/detail/unpack_flatten.hpp
@@ -25,7 +25,7 @@ BOOST_HANA_NAMESPACE_BEGIN namespace detail {
     template <std::size_t ...Lengths>
     struct flatten_indices {
         // avoid empty arrays by appending 0 to `lengths`
-        static constexpr std::size_t lengths[] = {Lengths..., 0};
+        static constexpr std::size_t lengths[sizeof...(Lengths) + 1] = {Lengths..., 0};
         static constexpr auto flat_length =
             detail::accumulate(lengths, lengths + sizeof...(Lengths), 0);
 
diff --git a/include/boost/hana/group.hpp b/include/boost/hana/group.hpp
index b21cd6b5f..52a3d64f7 100644
--- a/include/boost/hana/group.hpp
+++ b/include/boost/hana/group.hpp
@@ -78,7 +78,7 @@ BOOST_HANA_NAMESPACE_BEGIN
 
         template <bool ...b>
         struct group_indices {
-            static constexpr bool bs[] = {b...};
+            static constexpr bool bs[sizeof...(b)] = {b...};
             static constexpr std::size_t n_groups =
                     detail::count(bs, bs + sizeof(bs), false) + 1;
 
diff --git a/include/boost/hana/partition.hpp b/include/boost/hana/partition.hpp
index fdea39bcf..e2131f423 100644
--- a/include/boost/hana/partition.hpp
+++ b/include/boost/hana/partition.hpp
@@ -49,9 +49,9 @@ BOOST_HANA_NAMESPACE_BEGIN
     namespace detail {
         template <bool ...B>
         struct partition_indices {
-            static constexpr bool results[] = {B..., false}; // avoid empty array
+            static constexpr detail::array<bool, sizeof...(B)> results{{B...}};
             static constexpr std::size_t left_size =
-                detail::count(results, results + sizeof...(B), true);
+                detail::count(results.begin(), results.end(), true);
             static constexpr std::size_t right_size = sizeof...(B) - left_size;
 
             static constexpr auto compute_left() {