Errors with enums

[Kaba]

Consider the following code:

template <typename T>
class A
{
public:
class Direction
{
public:
enum Enum
{
Left, Right
};
};

void f()
{
Direction::Enum a = Direction::Left;
}
};

int main()
{
return 0;
}

Comeau and GCC (4.4.5) give a similar error:

"In member function ?void A<T>::f()?:
error: expected ?;? before ?a?"

Visual Studio 2008 compiles fine.

If the 'template <typename T>' is removed, then Comeau and Visual Studio
2008 compile it, while GCC gives:

/tmp/ccHbZ8n.eh_frame+0x12): undefined reference to
`__gxx_personality_v0'
collect2: ld returned 1 exit status

Explanations for the behaviours?

 

[Ian Collins]

Consider the following code:

template<typename T>
class A
{
public:
class Direction
{
public:
enum Enum
{
Left, Right
};
};

void f()
{
Direction::Enum a = Direction::Left;

typename Direction::Enum a = Direction::Left;

 

[Kaba]

typename Direction::Enum a = Direction::Left;

Why is typename needed here? Enum does not seem like a dependent type to
me.

 

[Johannes Schaub (litb)]

Why is typename needed here? Enum does not seem like a dependent type to
me.

It is, starting from C++03. See http://www.open-
std.org/jtc1/sc22/wg21/docs/cwg_defects.html#108

 

[Kaba]

It is, starting from C++03. See http://www.open-
std.org/jtc1/sc22/wg21/docs/cwg_defects.html#108

Interesting, thanks.