I do not know if the following example is considered valid code. I do not have
a copy of the standard.
The following code fails with g++-3.4 (GCC) 3.4.4 20050314 (prerelease)
(Debian 3.4.3-12).
error messages:
test.cpp:28: error: invalid explicit specialization before '>' token
test.cpp:28: error: explicit specialization in non-namespace scope `struct
heap<_T>'
test.cpp:28: error: enclosing class templates are not explicitly specialized
test.cpp:28: error: template parameters not used in partial specialization:
test.cpp:28: error: `_T'
test.cpp:31: error: `template<class _T> struct heap' used without template
parameters
test.cpp:31: error: `pointer' was not declared in this scope
test.cpp:31: error: template argument 1 is invalid
test.cpp:31: error: invalid type in declaration before ';' token
The error in line 28 occurs because the template is specialized in that scope
but declared in the base class. The error in line 31 seems to be a lookup
failure. Unless redefined 'pointer' should be inherited and visible.
--- test.cpp
template<typename _T>
class wrapper
{
public:
wrapper(_T t): _M_t(t) {}
operator _T& () { return _M_t; }
private:
_T _M_t;
};
struct container
{
struct pointer {};
struct forward {};
struct backward {};
struct bidirectional {};
struct randomaccess {};
template<typename _T> struct iterator;
};
template<typename _T>
struct heap: container
{
typedef _T value_type;
// does not make a difference
// template<typename _U> struct iterator;
template<> struct iterator<pointer>: wrapper<value_type *> {};
};
heap<int>::iterator<heap::pointer> p;
--
Summary: Templates and sub types are not inherited in g++
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: sven at clio dot in-berlin dot de
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i486-linux
GCC host triplet: i486-linux
GCC target triplet: i486-linux
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=21543
