C++ PATCH for c++/70468, ICE with constructor delegation via typedef.

[Jason Merrill]

tsubst_initializer_list needs the same error checking as
cp_parser_mem_initializer_list.

Tested x86_64-pc-linux-gnu, applying to trunk.

commit f51f20ad47d24aee54bfbe26f31c48e0f8a78def
Author: Jason Merrill <ja...@redhat.com>
Date:   Thu Feb 22 18:06:53 2018 -0500

            PR c++/70468 - ICE with constructor delegation via typedef.
    
            * pt.c (tsubst_initializer_list): Check for other mem-initializers
            with constructor delegation.

diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index bc03f0e818e..85d1adbbe3c 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -23558,6 +23558,7 @@ static tree
 tsubst_initializer_list (tree t, tree argvec)
 {
   tree inits = NULL_TREE;
+  tree target_ctor = error_mark_node;
 
   for (; t; t = TREE_CHAIN (t))
     {
@@ -23674,6 +23675,28 @@ tsubst_initializer_list (tree t, tree argvec)
               in_base_initializer = 0;
             }
 
+         if (target_ctor != error_mark_node
+             && init != error_mark_node)
+           {
+             error ("mem-initializer for %qD follows constructor delegation",
+                    decl);
+             return inits;
+           }
+         /* Look for a target constructor. */
+         if (init != error_mark_node
+             && decl && CLASS_TYPE_P (decl)
+             && same_type_p (decl, current_class_type))
+           {
+             maybe_warn_cpp0x (CPP0X_DELEGATING_CTORS);
+             if (inits)
+               {
+                 error ("constructor delegation follows mem-initializer for 
%qD",
+                        TREE_PURPOSE (inits));
+                 continue;
+               }
+             target_ctor = init;
+           }
+
           if (decl)
             {
               init = build_tree_list (decl, init);
diff --git a/gcc/testsuite/g++.dg/cpp0x/dc9.C b/gcc/testsuite/g++.dg/cpp0x/dc9.C
new file mode 100644
index 00000000000..b87f5ce618d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/dc9.C
@@ -0,0 +1,30 @@
+// PR c++/70468
+// { dg-do compile { target c++11 } }
+// { dg-additional-options -w }
+
+struct S {}; 
+
+template < typename = S > 
+class A 
+{
+public:
+  A () : f0 (), f1 () {}       // { dg-error "" }
+
+private:
+  typedef A<> f0; 
+  int f1;
+};
+
+template < typename = S, typename = S > 
+class B
+{
+}; 
+
+template < typename T1, typename T2 > 
+B < T1, T2 > &operator<< (B < T1, T2 >&, const int) 
+{
+  A<> (); 
+}
+
+template 
+B < S, S > &operator<< (B < S, S >&, const int);