[C++] Reference default argument falsely converted to pointer on instantiation of more than 2 explicit specializations

[C++] Reference default argument falsely converted to pointer on instantiation of more than 2 explicit specializations by CodingCat

Closed

as Fixed

Type:	Bug
ID:	718578
Opened:	1/14/2012 9:36:52 AM
Access Restriction:	Public
Moderator Decision:	Sent to Engineering Team for consideration

Workaround(s)

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User(s) can reproduce this bug

The VC++ 2010 compiler falsely converts default arguments of reference types to default arguments of pointer types when there are more than 2 explicit specializations of the corresponding function template and both are used in the same compilation unit. See details for example code.

Details (expand)

Visual Studio 2010 SP1

int& some_global_int()
{
    static int num;
    return num;
}

template <class Type>
int fun(int &i = some_global_int()) { return 6; }

template <>
int fun<int>(int &i) { return 2; }

template <>
int fun<float>(int &i) { return 3; }

int main()
{
    fun<int>();
    fun<float>(); // error C2440: 'default argument' : cannot convert from 'int *' to 'int &'
    return 0;
}

English

Windows 7

German

error C2440: 'default argument' : cannot convert from 'int *' to 'int &'

Should compile just fine.

0 attachments

Posted by Microsoft on 1/16/2012 at 12:30 PM

Hi:
A fix for this issue has been checked into the compiler sources. The fix should show up in the next release of Visual C++.

Xiang Fan
Visual C++ Team

Posted by MS-Moderator07 [Feedback Moderator] on 1/15/2012 at 7:05 PM

Thanks for your feedback.

We are rerouting this issue to the appropriate group within the Visual Studio Product Team for triage and resolution. These specialized experts will follow-up with your issue.

Posted by MS-Moderator01 on 1/14/2012 at 9:43 AM

Thank you for your feedback, we are currently reviewing the issue you have submitted. If this issue is urgent, please contact support directly(http://support.microsoft.com)