Explicit template member function call from return value of function

Question

i couldn't see this in the list of C++ standards not implemented <http://developers.sun.com/tools/cc/documentation/ss9_docs/mr/READMEs/c++.html> but sun studio 9 doesn't seem to allow explicit calls to template member functions where the left-hand-side is the return value of a function. here's a test-case:
template <typename T> class Ptr {
public:
  T* p_;
  Ptr(T* p) : p_(p) { }
  template <typename U> Ptr(const Ptr<U>& u) : p_(u.p_) { }
  template <typename U> Ptr<U> cast() const { return Ptr<U>(*this); }
class A {
class B : public A {
Ptr<A> test_cast_1(const Ptr<B>& b) { return b.cast<A>(); }
Ptr<A> test_cast_2(const Ptr<B>& b) { return Ptr<B>(b).cast<A>(); }sun studio 9 CC complains with the following message:
"sunstudio9-template-explicit-call.cc", line 18: Error: Unexpected type name "A" encountered.
"sunstudio9-template-explicit-call.cc", line 18: Error: Operand expected instead of ")".
2 Error(s) detected.
(line 18 is test_cast_2)
is this a known bug?
cheers,
/lib

Answer 1

you omitted the required keyword template:
template <typename T> class Ptr {
public:
  T* p_;
  Ptr(T* p) : p_(p) { }
  template <typename U> Ptr(const Ptr<U>& u) : p_(u.p_) { }
  template <typename U> Ptr<U> cast() const { return Ptr<U>(*this); }
class A {
class B : public A {
Ptr<A> test_cast_1(const Ptr<B>& b) { return b.cast<A>(); }
Ptr<A> test_cast_2(const Ptr<B>& b) { return Ptr<B>(b).template cast<A>(); }