https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81064
Nathan Sidwell <nathan at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
--- Comment #3 from Nathan Sidwell <nathan at gcc dot gnu.org> ---
Thanks for the reduced testcase. This is caused by:
2017-05-26 Nathan Sidwell <nat...@acm.org>
Implement DR2061
* name-lookup.c (push_inline_namespaces): New.
(push_namespace): Look inside inline namespaces.
http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#2061
I think I've implemented it correctly, and that the testcase is ill-formed.
Perhaps we could check whenever creating a new namepace that it doesn't cause
an ambiguity within the 'local' inline namespace tree. (though, such an
ambiguity could occur on declaring any new name, not just a namespace).
2061. Inline namespace after simplifications
Section: 7.3.1 [namespace.def] Status: CD4 Submitter: Richard Smith
Date: 2014-12-18
[Adopted at the February, 2016 meeting.]
After the resolution of issue 1795, 7.3.1 [namespace.def] paragraph 3 now says:
In a named-namespace-definition, the identifier is the name of the
namespace. If the identifier, when looked up (3.4.1 [basic.lookup.unqual]),
refers to a namespace-name (but not a namespace-alias) introduced in the
declarative region in which the named-namespace-definition appears, the
namespace-definition extends the previously-declared namespace. Otherwise, the
identifier is introduced as a namespace-name into the declarative region in
which the named-namespace-definition appears.
This appears to break code like the following:
namespace A {
inline namespace b {
namespace C {
template<typename T> void f();
}
}
}
namespace A {
namespace C {
template<> void f<int>() { }
}
}
because (by definition of “declarative region”) C cannot be used as an
unqualified name to refer to A::b::C within A if its declarative region is
A::b.
Proposed resolution (September, 2015):
Change 7.3.1 [namespace.def] paragraph 3 as follows:
In a named-namespace-definition, the identifier is the name of the
namespace. If the identifier, when looked up (3.4.1 [basic.lookup.unqual]),
refers to a namespace-name (but not a namespace-alias) that was introduced in
the declarative region namespace in which the named-namespace-definition
appears or that was introduced in a member of the inline namespace set of that
namespace, the namespace-definition extends the previously-declared namespace.
Otherwise, the identifier is introduced as a namespace-name into the
declarative region in which the named-namespace-definition appears.
