Prevent ill-formed instantiation of __invoke_of<...> during the evaluation of a bind expression. Fixes PR22003.
The SFINAE on the function __mu(Fn, Args...) that evaluates nested bind
expressions always tries to deduce the return type for Fn(Args...) even when Fn
is not a nested bind expression. This can cause hard compile errors when the
instantation of Fn(Args...) is ill-formed. This patch prevents the instantation
of __invoke_of<Fn, Args...> unless Fn is actually a bind expression.
Bug reportand patch from Michel Morin.
http://llvm.org/bugs/show_bug.cgi?id=22003
llvm-svn: 224753
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 279663c1b4bfcec7f849dd2becf207841c45c0cf
diff --git a/include/functional b/include/functional
index 416a9a9..d14b46b 100644
--- a/include/functional
+++ b/include/functional
@@ -1863,10 +1863,10 @@
template <class _Ti, class ..._Uj>
inline _LIBCPP_INLINE_VISIBILITY
-typename enable_if
+typename __lazy_enable_if
<
is_bind_expression<_Ti>::value,
- typename __invoke_of<_Ti&, _Uj...>::type
+ __invoke_of<_Ti&, _Uj...>
>::type
__mu(_Ti& __ti, tuple<_Uj...>& __uj)
{
diff --git a/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp b/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
new file mode 100644
index 0000000..33bf018
--- /dev/null
+++ b/test/std/utilities/function.objects/bind/func.bind/func.bind.bind/invoke_function_object.pass.cpp
@@ -0,0 +1,49 @@
+//===----------------------------------------------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <functional>
+
+// template<CopyConstructible Fn, CopyConstructible... Types>
+// unspecified bind(Fn, Types...);
+// template<Returnable R, CopyConstructible Fn, CopyConstructible... Types>
+// unspecified bind(Fn, Types...);
+
+// http://llvm.org/bugs/show_bug.cgi?id=22003
+
+#include <functional>
+
+struct DummyUnaryFunction
+{
+ template <typename S>
+ int operator()(S const & s) const { return 0; }
+};
+
+struct BadUnaryFunction
+{
+ template <typename S>
+ constexpr int operator()(S const & s) const
+ {
+ // Trigger a compile error if this function is instantiated.
+ // The constexpr is needed so that it is instantiated while checking
+ // __invoke_of<BadUnaryFunction &, ...>.
+ static_assert(!std::is_same<S, S>::value, "Shit");
+ return 0;
+ }
+};
+
+int main(int argc, char* argv[])
+{
+ // Check that BadUnaryFunction::operator()(S const &) is not
+ // instantiated when checking if BadUnaryFunction is a nested bind
+ // expression during b(0). See PR22003.
+ auto b = std::bind(DummyUnaryFunction(), BadUnaryFunction());
+ b(0);
+ auto b2 = std::bind<long>(DummyUnaryFunction(), BadUnaryFunction());
+ b2(0);
+}