[Bug c++/58449] New: templated cast operator and failed template deduction on copy-construction via assign operator

[Bug c++/58449] New: templated cast operator and failed template deduction on copy-construction via assign operator

[forestshade at hotmail dot de]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58449

            Bug ID: 58449
           Summary: templated cast operator and failed template deduction
                    on copy-construction via assign operator
           Product: gcc
           Version: 4.8.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: forestshade at hotmail dot de

The following code produces a compiler error:

-------------------------
#include <iostream>

using namespace std;

struct S {
};

class A {
public:
    A(void* ptr) : ptr(ptr) {}    
    void* ptr;

    template<typename T>
    operator const T&() const {
        return *static_cast<T*>(ptr);
    }
};

int main() {
    S test;    
    A a(&test);    
    S s = a;
    return 0;
}
-------------------------

while this one doesn't:

-------------------------
#include <iostream>

using namespace std;

struct S {
};

class A {
public:
    A(void* ptr) : ptr(ptr) {}    
    void* ptr;

    operator const S&() const {
        return *static_cast<S*>(ptr);
    }
};

int main() {
    S test;    
    A a(&test);    
    S s = a;
    return 0;
}
-------------------------

I'm not exactly sure if the standard allows the line "S s = a;" in this case
but the code above should either both succeed or both fail.

[Bug c++/58449] templated cast operator and failed template deduction on copy initialization

[redi at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58449

Jonathan Wakely <redi at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-09-17
     Ever confirmed|0                           |1

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
I think there's another bug similar to this but I can't find it now.

[Bug c++/58449] templated cast operator and failed template deduction on copy initialization

[gcc-im5revto at tobiasrenger dot name]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58449

Tobias Renger <gcc-im5revto at tobiasrenger dot name> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |gcc-im5revto at tobiasrenger dot n
                   |                            |ame

--- Comment #2 from Tobias Renger <gcc-im5revto at tobiasrenger dot name> ---
> I'm not exactly sure if the standard allows the line "S s = a;" in this case

I know this says nothing about standard conformance but both code examples
compile fine with clang 11.0.0 so this could actually be a bug in GCC.