Make sure resolve works and provide some protection against deleting the handler that originates from a specific sol::state. sol::state_view users will be left out in the dark, though.

docs/source/compilation.rst

@@ -5,15 +5,21 @@ getting good final product out of sol2
 
 For individiauls who use :doc:`usertypes<api/usertype>` a lot, they can find their compilation times increase. This is due to C++11 and C++14 not having very good facilities for handling template parameters and variadic template parameters. There are a few things in cutting-edge C++17 and C++Next that sol can use, but the problem is many people cannot work with the latest and greatest: therefore, we have to use older techniques that result in a fair amount of redundant function specializations that can be subject to the pickiness of the compiler's inlining and other such techniques.
 
+what to do
+----------
+
 Here are some notes on achieving better compile-times without sacrificing too much performance:
 
 * When you bind lots of usertypes, put them all in a *single* translation unit (one C++ file) so that it is not recompiled multiple times over, only to be discarded later by the linker.
 	- Remember that the usertype binding ends up being serialized into the Lua state, so you never need them to appear in a header and cause that same compilation overhead for every compiled unit in your project.
 * For extremely large usertypes, consider using :doc:`simple_usertype<api/simple_usertype>`.
 	- It performs much more work at runtime rather than compile-time, and should still give comparative performance (but it loses out in some cases for variable bindings or when you bind all functions to a usertype).
-* If you are developing a shared library, restrict your overall surface area by specifically and explicitly marking functions as visible and exported and letting everything else as hidden or invisible by default
+* If you are developing a shared library, restrict your overall surface area by specifically and explicitly marking functions as visible and exported and leaving everything else as hidden or invisible by default
 
 
+next steps
+----------
+
 The next step for Sol from a developer standpoint is to formally make the library a C++17 one. This would mean using Fold Expressions and several other things which will reduce compilation time drastically. Unfortunately, that means also boosting compiler requirements. While most wouldn't care, others are very slow to upgrade: finding the balance is difficult, and often we have to opt for backwards compatibility and fixes for bad / older compilers (of which there are many in the codebase already).
 
 Hopefully, as things progress, we move things forward.

single/sol/sol.hpp

@@ -20,8 +20,8 @@
 // CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 // This file was generated with a script.
-// Generated 2016-12-16 10:31:09.106965 UTC
+// Generated 2016-12-26 18:50:00.916890 UTC
-// This header was generated with sol v2.15.5 (revision 87f8456)
+// This header was generated with sol v2.15.5 (revision 3aa42c5)
 // https://github.com/ThePhD/sol2
 
 #ifndef SOL_SINGLE_INCLUDE_HPP
@@ -8531,9 +8531,10 @@ namespace sol {
 // beginning of sol/resolve.hpp
 
 namespace sol {
-	// Clang has distinct problems with constexpr arguments,
+	
-	// so don't use the constexpr versions inside of clang.
 #ifndef __clang__
+	// constexpr is fine for not-clang
+
 	namespace detail {
 		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
 		inline constexpr auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
@@ -8600,6 +8601,10 @@ namespace sol {
 		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
 	}
 #else
+
+	// Clang has distinct problems with constexpr arguments,
+	// so don't use the constexpr versions inside of clang.
+
 	namespace detail {
 		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
 		inline auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
@@ -8665,7 +8670,9 @@ namespace sol {
 	inline auto resolve(F&& f) -> decltype(detail::resolve_i(types<Sig...>(), std::forward<F>(f))) {
 		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
 	}
+
 #endif
+
 } // sol
 
 // end of sol/resolve.hpp
@@ -12829,7 +12836,19 @@ namespace sol {
 			stack::luajit_exception_handler(unique_base::get());
 		}
 
+		state(const state&) = delete;
+		state(state&&) = default;
+		state& operator=(const state&) = delete;
+		state& operator=(state&&) = default;
+
 		using state_view::get;
+
+		~state() {
+			auto& handler = protected_function::get_default_handler();
+			if (handler.lua_state() == this->lua_state()) {
+				protected_function::set_default_handler(reference());
+			}
+		}
 	};
 } // sol
 

sol/resolve.hpp

@@ -26,9 +26,10 @@
 #include "tuple.hpp"
 
 namespace sol {
-	// Clang has distinct problems with constexpr arguments,
+	
-	// so don't use the constexpr versions inside of clang.
 #ifndef __clang__
+	// constexpr is fine for not-clang
+
 	namespace detail {
 		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
 		inline constexpr auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
@@ -95,6 +96,10 @@ namespace sol {
 		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
 	}
 #else
+
+	// Clang has distinct problems with constexpr arguments,
+	// so don't use the constexpr versions inside of clang.
+
 	namespace detail {
 		template<typename R, typename... Args, typename F, typename = std::result_of_t<meta::unqualified_t<F>(Args...)>>
 		inline auto resolve_i(types<R(Args...)>, F&&)->R(meta::unqualified_t<F>::*)(Args...) {
@@ -160,7 +165,9 @@ namespace sol {
 	inline auto resolve(F&& f) -> decltype(detail::resolve_i(types<Sig...>(), std::forward<F>(f))) {
 		return detail::resolve_i(types<Sig...>(), std::forward<F>(f));
 	}
+
 #endif
+
 } // sol
 
 #endif // SOL_RESOLVE_HPP

sol/state.hpp

@@ -75,7 +75,19 @@ namespace sol {
 			stack::luajit_exception_handler(unique_base::get());
 		}
 
+		state(const state&) = delete;
+		state(state&&) = default;
+		state& operator=(const state&) = delete;
+		state& operator=(state&&) = default;
+
 		using state_view::get;
+
+		~state() {
+			auto& handler = protected_function::get_default_handler();
+			if (handler.lua_state() == this->lua_state()) {
+				protected_function::set_default_handler(reference());
+			}
+		}
 	};
 } // sol