https://llvm.org/bugs/show_bug.cgi?id=27221
Bug ID: 27221
Summary: member function of template instantiated even though
only declaration is needed
Product: clang
Version: unspecified
Hardware: PC
OS: Linux
Status: NEW
Severity: normal
Priority: P
Component: C++11
Assignee: unassignedclangb...@nondot.org
Reporter: rb...@eudoxos.de
CC: dgre...@apple.com, llvm-bugs@lists.llvm.org
Classification: Unclassified
This code fails to compile:
template<typename T>
struct X
{
X(X&&) { static_assert(sizeof(T) < 1, "Intentional Failure"); }
};
auto impl() -> X<int>;
auto test() -> decltype(impl())
{
return impl();
}
int main()
{
test();
}
My understanding is that it should compile just fine. I admit, I started a
discussion on stackoverflow for this (see
http://stackoverflow.com/questions/36371571/clang-and-gcc-vs-msvc-and-icc-is-a-static-assert-in-the-copy-move-constructor-r)
Citing from the answer I deem correct:
Copy elision requires declaration of copy/move constructors but doesn't require
definition.
Member function definitions of templates are not instantiated unless their
definitions are required.
If a definition is not instantiated it cannot be tested for being ill-formed.
References:
14.7.1.1 …The implicit instantiation of a class template specialization causes
the implicit instantiation of the declarations, but not of the definitions,
default arguments, or exception-specifications of the class member functions…
14.7.1.2 Unless a member of a class template… has been explicitly instantiated
or explicitly specialized, the specialization of the member is implicitly
instantiated when the specialization is referenced in a context that requires
the member definition to exist…
--
You are receiving this mail because:
You are on the CC list for the bug.
_______________________________________________
llvm-bugs mailing list
llvm-bugs@lists.llvm.org
http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-bugs
