diff --git a/src/script/context.cpp b/src/script/context.cpp
index cd8c12f9..b630daf4 100644
--- a/src/script/context.cpp
+++ b/src/script/context.cpp
@@ -265,12 +265,22 @@ ScriptValueP Context::makeClosure(const ScriptValueP& fun) {
 
 size_t Context::openScope() {
 	level += 1;
+	#ifdef _DEBUG
+		scopes.push_back(shadowed.size());
+		assert(scopes.size() == level);
+	#endif
 	return shadowed.size();
 }
 void Context::closeScope(size_t scope) {
 	assert(level > 0);
 	assert(scope <= shadowed.size());
 	level -= 1;
+	#ifdef _DEBUG
+		assert(!scopes.empty());
+		assert(scopes.back() == scope);
+		scopes.pop_back();
+		assert(scopes.size() == level);
+	#endif
 	// restore shadowed variables
 	while (shadowed.size() > scope) {
 		variables[shadowed.back().variable] = shadowed.back().value;
diff --git a/src/script/context.hpp b/src/script/context.hpp
index cc034eff..81da61a9 100644
--- a/src/script/context.hpp
+++ b/src/script/context.hpp
@@ -102,7 +102,11 @@ class Context {
 	/// Number of scopes opened
 	unsigned int level;
 	/// Stack of values
-	vector<ScriptValueP> stack;	
+	vector<ScriptValueP> stack;
+	#ifdef _DEBUG
+		/// The opened scopes, for sanity checking
+		vector<size_t> scopes;
+	#endif
 	
 	// utility types for dependency analysis
 	struct Jump;
diff --git a/src/script/dependency.cpp b/src/script/dependency.cpp
index ab4038df..7b22c3ef 100644
--- a/src/script/dependency.cpp
+++ b/src/script/dependency.cpp
@@ -159,7 +159,7 @@ ScriptValueP Context::dependencies(const Dependency& dep, const Script& script)
 				}
 				// unify bindings
 				FOR_EACH(v, j->bindings) {
-					unify(variables[v.variable].value, v.value.value);
+					setVariable(v.variable, unified(variables[v.variable].value, v.value.value) );
 				}
 				delete j;
 			}
@@ -368,9 +368,8 @@ void Context::getBindings(size_t scope, vector<Binding>& bindings) {
 }
 
 void Context::resetBindings(size_t scope) {
-	// same as closeScope()
-	while (shadowed.size() > scope) {
-		variables[shadowed.back().variable] = shadowed.back().value;
-		shadowed.pop_back();
-	}
+	// close and re-open the scope
+	closeScope(scope);
+	size_t same_scope = openScope();
+	assert(scope == same_scope);
 }