[PR c++/84375] Fix ICE after bad friend

https://gcc.gnu.org/ml/gcc-patches/2018-02/msg00987.html
	PR c++/84375
	* name-lookup.c (do_pushdecl): Bail out on bad local friend injection.

	* g++.dg/lookup/pr84375.C: New.

From-SVN: r257739

gcc/cp/ChangeLog

+2018-02-16  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/84375
+	* name-lookup.c (do_pushdecl): Bail out on bad local friend injection.
+
 2018-02-15  Jason Merrill  <jason@redhat.com>
 
 	PR c++/83227 - C++17 ICE with init-list derived-to-base conversion.

gcc/cp/name-lookup.c

@@ -3079,12 +3079,16 @@ do_pushdecl (tree decl, bool is_friend)
 	  if (is_friend)
 	    {
 	      if (level->kind != sk_namespace)
+		{
 		  /* In a local class, a friend function declaration must
 		     find a matching decl in the innermost non-class scope.
 		     [class.friend/11] */
 		  error ("friend declaration %qD in local class without "
 			 "prior local declaration", decl);
-	      else if (!flag_friend_injection)
+		  /* Don't attempt to push it.  */
+		  return error_mark_node;
+		}
+	      if (!flag_friend_injection)
 		/* Hide it from ordinary lookup.  */
 		DECL_ANTICIPATED (decl) = DECL_HIDDEN_FRIEND_P (decl) = true;
 	    }

gcc/testsuite/ChangeLog

+2018-02-16  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/84375
+	* g++.dg/lookup/pr84375.C: New.
+
 2018-02-14  Oleg Endo  <olegendo@gcc.gnu.org>
 
 	PR target/83831

gcc/testsuite/g++.dg/lookup/pr84375.C

+// PR c++/84375 ICE after error
+
+void foo()
+{
+  struct A
+  {
+    friend void A(); // { dg-error "local class without prior local" }
+  };
+}