re PR c++/66445 (ICE with lambda in stmt expression in a template)

	PR c++/66445
	* constexpr.c (potential_constant_expression_1): Handle a
	DECL_EXPR of TYPE_DECL.

From-SVN: r224382

gcc/cp/ChangeLog

 2015-06-11  Jason Merrill  <jason@redhat.com>
 
+	PR c++/66445
+	* constexpr.c (potential_constant_expression_1): Handle a
+	DECL_EXPR of TYPE_DECL.
+
 	PR c++/66450
 	* constexpr.c (cxx_eval_store_expression): Avoid messing up outer
 	ctx->ctor.

gcc/cp/constexpr.c

@@ -4462,6 +4462,11 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict,
 	}
       return false;
 
+    case TYPE_DECL:
+    case TAG_DEFN:
+      /* We can see these in statement-expressions.  */
+      return true;
+
     default:
       if (objc_is_property_ref (t))
 	return false;

gcc/testsuite/g++.dg/ext/stmtexpr18.C

+// PR c++/66445
+// { dg-options "" }
+
+template <typename> void foo ()
+{
+  int a = ({ struct A{} b; 42; });
+}