re PR c++/83796 (Abstract classes allowed to be instantiated when initialised as default parameter to function or constructor)

/cp
2018-02-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/83796
	* call.c (convert_like_real): If w're initializing from {} explicitly
	call abstract_virtuals_error_sfinae.

/testsuite
2018-02-01  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/83796
	* g++.dg/cpp0x/abstract-default1.C: New.

From-SVN: r257298