diff --git a/src/parse.rs b/src/parse.rs
index 77b24b5..bc2c953 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -93,7 +93,7 @@ impl AssertSupported for FunctionDefinition {
     fn assert_supported(&self) {
         self.specifiers.assert_supported();
         self.declarator.assert_supported();
-        self.declarations.is_empty();
+        assert!(self.declarations.is_empty());
         self.statement.assert_supported();
     }
 }
diff --git a/tests/fuzz.py b/tests/fuzz.py
index da9ff98..485bc03 100644
--- a/tests/fuzz.py
+++ b/tests/fuzz.py
@@ -95,6 +95,14 @@ if __name__ == "__main__":
     raw_test_file = "raw_test.c"
     test_file = "test.c"
     try:
+        print("Building KECC..")
+        try:
+            proc = subprocess.Popen(["cargo", "build", "--release"], cwd=tests_dir)
+            proc.communicate()
+        except subprocess.TimeoutExpired as e:
+            proc.kill()
+            raise e
+
         if args.num is None:
             print("Fuzzing with infinitely many test cases.  Please press [ctrl+C] to break.")
             iterator = itertools.count(0)