Fix copy_node of TEMPLATE_INFO.

build_clone uses copy_node to duplicate the TEMPLATE_INFO for a clone, but
this clears TREE_CHAIN, which was TI_ARGS in a TEMPLATE_INFO.

	* cp-tree.h (struct tree_template_info): Use tree_base instead of
	tree_common.  Add tmpl and args fields.
	(TI_TEMPLATE, TI_ARGS): Adjust.

From-SVN: r273943

gcc/cp/ChangeLog

+2019-07-31  Jason Merrill  <jason@redhat.com>
+
+	Fix copy_node of TEMPLATE_INFO.
+	* cp-tree.h (struct tree_template_info): Use tree_base instead of
+	tree_common.  Add tmpl and args fields.
+	(TI_TEMPLATE, TI_ARGS): Adjust.
+
 2019-07-30  Martin Liska  <mliska@suse.cz>
 
 	PR tree-optimization/91270

gcc/cp/cp-objcp-common.c

@@ -373,7 +373,6 @@ cp_common_init_ts (void)
   MARK_TS_COMMON (TEMPLATE_TYPE_PARM);
   MARK_TS_COMMON (TEMPLATE_PARM_INDEX);
   MARK_TS_COMMON (OVERLOAD);
-  MARK_TS_COMMON (TEMPLATE_INFO);
   MARK_TS_COMMON (TYPENAME_TYPE);
   MARK_TS_COMMON (TYPEOF_TYPE);
   MARK_TS_COMMON (UNDERLYING_TYPE);

gcc/cp/cp-tree.h

@@ -1437,7 +1437,9 @@ typedef struct qualified_typedef_usage_s qualified_typedef_usage_t;
   (TREE_LANG_FLAG_1 (TEMPLATE_INFO_CHECK (NODE)))
 
 struct GTY(()) tree_template_info {
-  struct tree_common common;
+  struct tree_base base;
+  tree tmpl;
+  tree args;
   vec<qualified_typedef_usage_t, va_gc> *typedefs_needing_access_checking;
 };
 
@@ -3420,8 +3422,10 @@ struct GTY(()) lang_decl {
    ? (TYPE_LANG_SLOT_1 (NODE) = (VAL))				\
    : (DECL_TEMPLATE_INFO (TYPE_NAME (NODE)) = (VAL)))
 
-#define TI_TEMPLATE(NODE) TREE_TYPE (TEMPLATE_INFO_CHECK (NODE))
-#define TI_ARGS(NODE) TREE_CHAIN (TEMPLATE_INFO_CHECK (NODE))
+#define TI_TEMPLATE(NODE) \
+  ((struct tree_template_info*)TEMPLATE_INFO_CHECK (NODE))->tmpl
+#define TI_ARGS(NODE) \
+  ((struct tree_template_info*)TEMPLATE_INFO_CHECK (NODE))->args
 #define TI_PENDING_TEMPLATE_FLAG(NODE) \
   TREE_LANG_FLAG_1 (TEMPLATE_INFO_CHECK (NODE))
 /* For a given TREE_VEC containing a template argument list,