diff --git a/SConstruct b/SConstruct
index c5d0df6..282fb9e 100644
--- a/SConstruct
+++ b/SConstruct
@@ -33,6 +33,7 @@ env = Environment(
     "-g",
     "-fPIC",
     "-O2",
+    "-Wunused",
     "-Werror",
   ] + ccflags_asan,
   LDFLAGS=ldflags_asan,
diff --git a/can/parser.cc b/can/parser.cc
index 54e4ebe..5addd41 100644
--- a/can/parser.cc
+++ b/can/parser.cc
@@ -171,7 +171,6 @@ CANParser::CANParser(int abus, const std::string& dbc_name,
 
 void CANParser::UpdateCans(uint64_t sec, const capnp::List<cereal::CanData>::Reader& cans) {
     int msg_count = cans.size();
-    uint64_t p;
 
     DEBUG("got %d messages\n", msg_count);