Re: Internal compiler error on template of template

[Alexandre Oliva <oliva at dcc dot unicamp dot br>]

Guillaume Laurent <glaurent@worldnet.fr> writes:

> The following code produces an internal compiler error with egcs 1.0.3:

I was unable to reproduce the ICE with egcs 1.0.3 on
sparc-sun-solaris2.5; instead I got:

test2.cc:9: sorry, not implemented: `field_decl' not supported by dump_type
test2.cc: In function `void tfunc2<R>(class Foo *, void *)':
test2.cc:9: conversion from `void *' to non-scalar type `' requested

Nevertheless, it seems to me that your template function declaration
is not correct:

> template <class T>
> template <class R>
> void tfunc2(T* objptr, void *_methodptr)

This kind of syntax is used to define template member-functions of
template classes, like this:

template <class T> class foo { template <class T2> void bar(); };

template <class T> template <class T2> void foo<T>::bar<T2>() {}

However, I'm not sure the syntax is invalid.  Anyway, I'd recomment
you to use the notation:

template <class R, class T>

because the template argument R cannot be deduced, so you'll have to
specify it whenever you call tfunc2:

> void meta_tfunc(Foo *f, int (Foo::*m_ptr)(void))
> {
>   tfunc2(f, (void*)0);

    tfunc2<int>(f, (void*)0); 

Furthermore, in tfunc2, you try to cast `void*' to a pointer to
member, but this is impossible.  In C++, one cannot convert pointers
to non-members to pointers to members, nor the converse.

-- 
Alexandre Oliva
mailto:oliva@dcc.unicamp.br mailto:aoliva@acm.org
http://www.dcc.unicamp.br/~oliva
Universidade Estadual de Campinas, SP, Brasil