[patch libstdc++] Fix assignability check in uninitialized_copy

[Eelis]

On 2014-12-28 00:18, Eelis wrote:
> Trivial fix attached.

Please don't commit this patch.

I just noticed that the assignability test is wrong in an additional way: it should look at assignability of /output/ elements, not /input/ elements.

As a result, this code is currently rejected (because uninitialized_copy doesn't notice in time that chars can't be assigned to Xs):

	struct X
	{
		X() = default;
		X(char) {}
		X(X const &) = default;
		X & operator=(X const&) = default;

		X & operator=(char) = delete;
	};

	#include <memory>

	int main()
	{
		char a[100];
		X b[100];

		std::uninitialized_copy(a, a+10, b);
	}

Updated fix attached. With it, the code is accepted again. Testing as we speak.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: fix-uninitialized-copy-assignability-check.patch
Type: text/x-patch
Size: 1374 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/libstdc++/attachments/20141228/d992502e/attachment.bin>