re PR c++/68434 ([concepts] function tsubst sets TYPE_CANONICAL before setting a…

re PR c++/68434 ([concepts] function tsubst sets TYPE_CANONICAL before setting a type's PLACEHOLDER_TYPE_CONSTRAINTS)

	PR c++/68434

	* pt.c (tsubst): Set PLACEHOLDER_TYPE_CONSTRAINTS before
	calling canonical_type_parameter.

From-SVN: r230909

gcc/cp/ChangeLog

+2015-11-25  Ryan Burn  <contact@rnburn.com>
+
+	PR c++/68434
+	* pt.c (tsubst): Set PLACEHOLDER_TYPE_CONSTRAINTS before
+	calling canonical_type_parameter.
+
 2015-11-25  Jason Merrill  <jason@redhat.com>
 
 	* lambda.c (maybe_add_lambda_conv_op): Only set

gcc/cp/pt.c

@@ -12977,6 +12977,12 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 		TYPE_POINTER_TO (r) = NULL_TREE;
 		TYPE_REFERENCE_TO (r) = NULL_TREE;
 
+		/* Propagate constraints on placeholders.  */
+                if (TREE_CODE (t) == TEMPLATE_TYPE_PARM)
+                  if (tree constr = PLACEHOLDER_TYPE_CONSTRAINTS (t))
+		    PLACEHOLDER_TYPE_CONSTRAINTS (r)
+		      = tsubst_constraint (constr, args, complain, in_decl);
+
 		if (TREE_CODE (r) == TEMPLATE_TEMPLATE_PARM)
 		  /* We have reduced the level of the template
 		     template parameter, but not the levels of its
@@ -12991,12 +12997,6 @@ tsubst (tree t, tree args, tsubst_flags_t complain, tree in_decl)
 		else
 		  TYPE_CANONICAL (r) = canonical_type_parameter (r);
 
-		/* Propagate constraints on placeholders.  */
-                if (TREE_CODE (t) == TEMPLATE_TYPE_PARM)
-                  if (tree constr = PLACEHOLDER_TYPE_CONSTRAINTS (t))
-		    PLACEHOLDER_TYPE_CONSTRAINTS (r)
-		      = tsubst_constraint (constr, args, complain, in_decl);
-
 		if (code == BOUND_TEMPLATE_TEMPLATE_PARM)
 		  {
 		    tree argvec = tsubst (TYPE_TI_ARGS (t), args,

gcc/testsuite/g++.dg/concepts/pr68434.C

+// { dg-options "-std=c++1z" }
+
+template <class>
+concept bool C1 () {
+  return true;
+}
+
+template <class>
+concept bool C2 () {
+  return true;
+}
+
+template <class Expr>
+concept bool C3 () {
+  return requires (Expr expr) {
+      {expr}->C1;
+      {expr}->C2;
+  };
+}
+
+auto f (C3);