[Bug c++/53573] template type dependent name resolution broken

["keean at fry-it dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53573

--- Comment #12 from Keean Schupke <keean@fry-it.com> 2012-06-05 11:14:00 UTC ---
(In reply to comment #10)

although -fpermissive allows the code to compile (in some circumstances) it
does not in all, and it also produces incorrect output, for example:



#include <iostream>

char g(char x) {
    return x - 1;
}

template <typename T> T f(T t) {
    return g(t);
}

double g(double x) {
    return x;
}

main() {
    double x(f(1.0L));
    std::cout << x << "\n";
}



will output "0" instead of "1" choosing the wrong overloaded function. In the
case below:



#include <iostream>

char g(char x) {
    return x - 1;
}

int g(int x) {
    return x + 1;
}

template <typename T> T f(T t) {
    return g(t);
}

double g(double x) {
    return x;
}

main() {
    double x(f(1.0L));
    std::cout << x << "\n";
}



compilation still fails with:

test.cpp: In instantiation of âT f(T) [with T = long double]â:
test.cpp:20:17:   required from here
test.cpp:12:12: error: call of overloaded âg(long double&)â is ambiguous
test.cpp:12:12: note: candidates are:
test.cpp:3:6: note: char g(char)
test.cpp:7:5: note: int g(int)

even with -fpermissive 

> (In reply to comment #6)
> > The suggested work around in the error message 'adding -fpermissive' to
> > gcc-4.7.0 does not fix the problem as suggested by the error message. 
> 
> As Manu says, -fpermissive changes the error to a warning, allowing the code to
> compile. Please check it again.
> 
> I'm going to close this, as I think G++ handles comment 1 correctly and both
> EDG and Clang agree.
> 
> I didn't check all your other examples in detail but I don't think they show
> anything different: ADL doesn't find anything for built-in types such as int or
> char.