https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70563
Bug ID: 70563
Summary: SFINEA fails when trying invalid template
instantiation
Product: gcc
Version: 5.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: webmaster at havogt dot de
Target Milestone: ---
vogt@fermi03:~/temp2> cat test_SFINAE_with_template_binding.ii
# 1 "test_SFINAE_with_template_binding.cc"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "/usr/include/stdc-predef.h" 1 3 4
# 1 "<command-line>" 2
# 1 "test_SFINAE_with_template_binding.cc"
template<typename... T> using void_t = void;
template<typename T> struct TemporaryBindObject
{
};
struct MyTrueType
{
static constexpr bool value = true;
};
struct MyFalseType
{
static constexpr bool value = false;
};
template<template<typename...> class Dest> struct TestValidBind
{
template<typename T, typename = void_t<>> struct toTypesOf : MyFalseType
{};
template<template<typename...> class Src, typename... Ts> struct
toTypesOf<Src<Ts...>, void_t<Dest<Ts...,float>>> : MyTrueType
{};
};
template<typename T> struct OneParamStruct
{
};
template<typename T1, typename T2> struct TwoParamStruct
{
};
using tmp = TemporaryBindObject<int>;
int main()
{
bool value1 =
TestValidBind<TwoParamStruct>::toTypesOf<TemporaryBindObject<int>>::value;
bool value2 =
TestValidBind<OneParamStruct>::toTypesOf<TemporaryBindObject<int>>::value;
}
vogt@fermi03:~/temp2> g++-5 -std=c++11 test_SFINAE_with_template_binding.ii
test_SFINAE_with_template_binding.cc: In function ‘int main()’:
test_SFINAE_with_template_binding.cc:41:16: error: incomplete type
‘TestValidBind<OneParamStruct>::toTypesOf<TemporaryBindObject<int> >’ used in
nested name specifier
bool value2 =
TestValidBind<OneParamStruct>::toTypesOf<TemporaryBindObject<int>>::value;
^
vogt@fermi03:~/temp2> g++-5 --version
g++-5 (SUSE Linux) 5.3.1 20160301 [gcc-5-branch revision 233849]
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
The example works with clang. I am not a standard expert to decide who is
right. Actually, a simplified version works with gcc, however I don't see the
reason why this shouldn't, see http://stackoverflow.com/a/36411945/5085250
Same problem with
vogt@fermi03:~/temp2> g++-6 --version
g++-6 (SUSE Linux) 6.0.0 20160324 (experimental) [trunk revision 234449]
Copyright (C) 2016 Free Software Foundation, Inc.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
