1 files changed, 1 insertions, 0 deletions
diff --git a/src/gc.cpp b/src/gc.cpp
index 01848d2..9367921 100644
--- a/src/gc.cpp
+++ b/src/gc.cpp
@@ -79,6 +79,7 @@ GC::collect(const Roots& roots)
 
 		if ((*i)->marked()) {
 			(*i)->mark(false);
+			assert(!(*i)->marked());
 		} else {
 			if ((*i)->tag() == Object::AST)
 				((AST*)*i)->~AST();