[SQUASH] Assert special nodes are null.

Author: chriseth

libyul/ControlFlowSideEffectsCollector.cpp

@@ -80,9 +80,7 @@ void ControlFlowBuilder::operator()(Switch const& _switch)
 void ControlFlowBuilder::operator()(FunctionDefinition const& _function)
 {
 	ScopedSaveAndRestore currentNode(m_currentNode, nullptr);
-	ScopedSaveAndRestore leaveNode(m_leave, nullptr);
-	ScopedSaveAndRestore breakNode(m_break, nullptr);
-	ScopedSaveAndRestore continueNode(m_continue, nullptr);
+	yulAssert(!m_leave && !m_break && !m_continue, "Function hoister has not been used.");
 
 	FunctionFlow flow;
 	flow.exit = newNode();
@@ -95,6 +93,8 @@ void ControlFlowBuilder::operator()(FunctionDefinition const& _function)
 	m_currentNode->successors.emplace_back(flow.exit);
 
 	m_functionFlows[_function.name] = move(flow);
+
+	m_leave = nullptr;
 }
 
 void ControlFlowBuilder::operator()(ForLoop const& _for)