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Description
Following from wlav/cppyy#201, it seems there is an issue with (ROOT's) cppyy's handling of SFINAE functions with variadic template arguments.
Reproducer
import ROOT
import cppyy
cppyy.cppdef('''
template <typename T> struct TestSfinae {
template <typename U, typename V = T,
std::enable_if_t<std::is_arithmetic_v<V>, bool> = false>
auto test_single(U arg) {
std::cout << "good" << std::endl;
return 0;
}
template <typename... Args, typename V = T,
std::enable_if_t<std::is_arithmetic_v<V>, bool> = false>
auto test_pack(Args... args) {
std::cout << "good" << std::endl;
return 0;
}
};
''')
# call from cling
cppyy.cppdef('''auto testing = TestSfinae<float>();''')
cppyy.cppdef('''auto single_call = testing.test_single(1);''') # good
cppyy.cppdef('''auto pack_call = testing.test_pack(1,2,3);''') # good
# call from bindings
testing = cppyy.gbl.TestSfinae['float']()
testing.test_single(1) # good
testing.test_pack(1,2,3) # failsROOT version
------------------------------------------------------------------
| Welcome to ROOT 6.28/06 https://root.cern |
| (c) 1995-2023, The ROOT Team; conception: R. Brun, F. Rademakers |
| Built for macosx64 on Sep 17 2023, 12:38:14 |
| From heads/latest-stable@7745d36d |
| With Apple clang version 14.0.3 (clang-1403.0.22.14.1) |
| Try '.help'/'.?', '.demo', '.license', '.credits', '.quit'/'.q' |
------------------------------------------------------------------
Installation method
build from source
Operating system
MacOS
Additional context
input_line_24:6:70: error: no matching member function for call to 'test_pack'
new (ret) (int) (((TestSfinae<float>*)obj)->TestSfinae<float>::test_pack<int, int, int, float, false>(*(int*)args[0], *(int*)args[1],
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
input_line_18:11:8: note: candidate template ignored: invalid explicitly-specified argument for template parameter 'Args'
auto test_pack(Args... args) {
^