re PR c++/50491 ([C++0x] [4.6/4.7 Regression] "unexpected ast of kind using_decl" on call to using'ed grandparent member function)

/cp
2011-09-22  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/50491
	* semantics.c (potential_constant_expression_1): Handle USING_DECL.

/testsuite
2011-09-22  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/50491
	* g++.dg/cpp0x/pr50491.C: New.

From-SVN: r179109