[Bug c++/40685] New: explicit constructor is used where only implicit ctors are allowed

kretz at kde dot org gcc-bugzilla@gcc.gnu.org
Wed Jul 8 16:03:00 GMT 2009


The following testcase fails on g++ 4.4.0 and 4.3.2:

#include <cstdlib>

enum Enum {
    Foo
};

class A
{
    public:
        A(int y) : x(y) {}
        explicit A(Enum) : x(1) {}

        int x;
};

static void fun(A a = Foo)
{
    if (a.x != static_cast<int>(Foo)) {
        abort();
    }
}

int main()
{
    fun();
    return 0;
}

If the A(int) ctor is removed the program does not compile, as is expected. If
the line "A a = Foo" appears inside the function instead of the parameter list
then g++ correctly uses the A(int) ctor.

While on that topic: The code above was meant to use the Enum ctor, it would be
nice if g++ emits a warning about the emitted code probably using the wrong
ctor.


-- 
           Summary: explicit constructor is used where only implicit ctors
                    are allowed
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kretz at kde dot org
 GCC build triplet: x86_64-unknown-linux-gnu
  GCC host triplet: x86_64-unknown-linux-gnu
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=40685



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