re PR c++/66536 (ICE in build_ctor_subob_ref, at cp/tree.c:2534)

	PR c++/66536
	* tree.c (replace_placeholders_r) [CONSTRUCTOR]: Handle type
	mismatch.

From-SVN: r224534

gcc/cp/ChangeLog

 2015-06-16  Jason Merrill  <jason@redhat.com>
 
+	PR c++/66536
+	* tree.c (replace_placeholders_r) [CONSTRUCTOR]: Handle type
+	mismatch.
+
 	PR c++/58063
 	* tree.c (bot_manip): Remap SAVE_EXPR.
 

gcc/cp/tree.c

@@ -2599,7 +2599,12 @@ replace_placeholders_r (tree* t, int* walk_subtrees, void* data_)
 	    if (TREE_CODE (*valp) == CONSTRUCTOR
 		&& AGGREGATE_TYPE_P (type))
 	      {
-		subob = build_ctor_subob_ref (ce->index, type, obj);
+		/* If we're looking at the initializer for OBJ, then build
+		   a sub-object reference.  If we're looking at an
+		   initializer for another object, just pass OBJ down.  */
+		if (same_type_ignoring_top_level_qualifiers_p
+		    (TREE_TYPE (*t), TREE_TYPE (obj)))
+		  subob = build_ctor_subob_ref (ce->index, type, obj);
 		if (TREE_CODE (*valp) == TARGET_EXPR)
 		  valp = &TARGET_EXPR_INITIAL (*valp);
 	      }

gcc/testsuite/g++.dg/cpp1y/var-templ30.C

+// PR c++/66536
+// { dg-do compile { target c++14 } }
+
+template <typename> struct make_impl;
+struct Tuple;
+template <> struct make_impl<Tuple> {};
+struct A {
+  template <typename X> auto operator()(X) { return make_impl<Tuple>(); }
+};
+template <typename> A make;
+template <typename _Tp, int> struct array { _Tp _M_elems; };
+struct Tracked {
+  Tracked(int);
+};
+struct B {
+  Tracked tracker{0};
+};
+template <int> using ct_eq = B;
+auto eq_arrays = make<Tuple>(array<ct_eq<0>, 0>{});