https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77386
Bug ID: 77386 Summary: Explicit constructor is allowed causing ambiguous initialization call when it shouldn't be allowed Product: gcc Version: 4.9.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: hpmv at google dot com Target Milestone: --- Using g++ 4.8.4, compiling the following code struct X{ X(int, int) {} }; struct Y { explicit Y(X) {} explicit Y(int, int) {} }; int main() { Y({1, 2}); } with the command line g++ -Wall -Wextra --std=c++11 main.cpp fails with the errors main.cpp: In function ‘int main()’: main.cpp:11:11: error: call of overloaded ‘Y(<brace-enclosed initializer list>)’ is ambiguous Y({1, 2}); ^ main.cpp:11:11: note: candidates are: main.cpp:6:11: note: Y::Y(X) explicit Y(X) {} ^ main.cpp:5:8: note: constexpr Y::Y(const Y&) struct Y { ^ main.cpp:5:8: note: constexpr Y::Y(Y&&) This doesn't make sense because the overload Y::Y(const Y&) and Y::Y(Y&&) should not be considered since it's not possible to interpret {1, 2} as Y(1, 2) due to that constructor being marked explicit. The code compiles in clang 3.4.