PR c++/68666 - member variable template-id

	* typeck.c (finish_class_member_access_expr): Handle variable
	template-id.
	* pt.c (lookup_and_finish_template_variable): No longer static.
	* cp-tree.h: Declare it.

From-SVN: r244599

gcc/cp/ChangeLog

+2017-01-18  Jason Merrill  <jason@redhat.com>
+
+	PR c++/68666 - member variable template-id
+	* typeck.c (finish_class_member_access_expr): Handle variable
+	template-id.
+	* pt.c (lookup_and_finish_template_variable): No longer static.
+	* cp-tree.h: Declare it.
+
 2017-01-18  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/78488

gcc/cp/cp-tree.h

@@ -6449,6 +6449,7 @@ extern cp_expr perform_koenig_lookup		(cp_expr, vec<tree, va_gc> *,
 						 tsubst_flags_t);
 extern tree finish_call_expr			(tree, vec<tree, va_gc> **, bool,
 						 bool, tsubst_flags_t);
+extern tree lookup_and_finish_template_variable (tree, tree, tsubst_flags_t = tf_warning_or_error);
 extern tree finish_template_variable		(tree, tsubst_flags_t = tf_warning_or_error);
 extern cp_expr finish_increment_expr		(cp_expr, enum tree_code);
 extern tree finish_this_expr			(void);

gcc/cp/pt.c

@@ -9035,7 +9035,7 @@ finish_template_variable (tree var, tsubst_flags_t complain)
 /* Construct a TEMPLATE_ID_EXPR for the given variable template TEMPL having
    TARGS template args, and instantiate it if it's not dependent.  */
 
-static tree
+tree
 lookup_and_finish_template_variable (tree templ, tree targs,
 				     tsubst_flags_t complain)
 {

gcc/cp/typeck.c

@@ -2875,7 +2875,10 @@ finish_class_member_access_expr (cp_expr object, tree name, bool template_p,
 	  tree templ = member;
 
 	  if (BASELINK_P (templ))
-	    templ = lookup_template_function (templ, template_args);
+	    member = lookup_template_function (templ, template_args);
+	  else if (variable_template_p (templ))
+	    member = (lookup_and_finish_template_variable
+		      (templ, template_args, complain));
 	  else
 	    {
 	      if (complain & tf_error)

gcc/testsuite/g++.dg/concepts/var-templ3.C

+// PR c++/68666
+// { dg-options "-std=c++1z -fconcepts" }
+
+struct A {
+  template <class>
+  static constexpr bool val = true;
+};
+
+template <class T>
+concept bool C = A::val<T>;
+
+C{T} struct B {};

gcc/testsuite/g++.dg/cpp1y/var-templ55.C

+// { dg-do compile { target c++14 } }
+
+template <class T> struct A {
+  template <class U> static const U x = 1;
+  static const int y = 2;
+};
+
+int main() {
+  A<int> a;
+  int y = a.y;         // OK
+  int x = a.x<int>;     // ???
+}