1 files changed, 4 insertions, 0 deletions
diff --git a/build2/bin/rule b/build2/bin/rule
index f733e5a..5031be1 100644
--- a/build2/bin/rule
+++ b/build2/bin/rule
@@ -17,6 +17,8 @@ namespace build2
     class obj_rule: public rule
     {
     public:
+      obj_rule () {}
+
       virtual match_result
       match (action, target&, const string& hint) const override;
 
@@ -27,6 +29,8 @@ namespace build2
     class lib_rule: public rule
     {
     public:
+      lib_rule () {}
+
       virtual match_result
       match (action, target&, const string& hint) const override;