PR c++/59480, DR 136

PR c++/59480, DR 136

/cp
2018-08-07  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/59480, DR 136
	* decl.c (check_no_redeclaration_friend_default_args): New.
	(duplicate_decls): Use the latter; also check that a friend
	declaration specifying default arguments is a definition.

/testsuite
2018-08-07  Paolo Carlini  <paolo.carlini@oracle.com>

	PR c++/59480, DR 136
	* g++.dg/other/friend8.C: New.
	* g++.dg/other/friend9.C: Likewise.
	* g++.dg/other/friend10.C: Likewise.
	* g++.dg/other/friend11.C: Likewise.
	* g++.dg/other/friend12.C: Likewise.
	* g++.dg/other/friend13.C: Likewise.
	* g++.dg/other/friend14.C: Likewise.
	* g++.dg/other/friend15.C: Likewise.
	* g++.dg/parse/defarg4.C: Compile with -fpermissive -w.
	* g++.dg/parse/defarg8.C: Likewise.

From-SVN: r263361