Copy map before looping over it because it might be modified.

libdevcore/CommonData.h

@@ -349,6 +349,24 @@ std::vector<T> keysOf(std::unordered_map<T, U> const& _m)
 	return ret;
 }
 
+template<class T, class U>
+std::vector<U> valuesOf(std::map<T, U> const& _m)
+{
+	std::vector<U> ret(_m.size());
+	for (auto const& i: _m)
+		ret.push_back(i.second);
+	return ret;
+}
+
+template<class T, class U>
+std::vector<U> valuesOf(std::unordered_map<T, U> const& _m)
+{
+	std::vector<U> ret(_m.size());
+	for (auto const& i: _m)
+		ret.push_back(i.second);
+	return ret;
+}
+
 template <class T, class V>
 bool contains(T const& _t, V const& _v)
 {

libethcore/Common.h

@@ -154,9 +154,9 @@ public:
 		friend class Signal;
 
 	public:
-		~HandlerAux() { if (m_s) m_s->m_fire.erase(m_i); m_s = nullptr; }
+		~HandlerAux() { if (m_s) m_s->m_fire.erase(m_i); }
 		void reset() { m_s = nullptr; }
-		void fire(Args&&... _args) { m_h(std::forward<Args>(_args)...); }
+		void fire(Args const&... _args) { m_h(_args...); }
 
 	private:
 		HandlerAux(unsigned _i, Signal* _s, Callback const& _h): m_i(_i), m_s(_s), m_h(_h) {}
@@ -181,11 +181,11 @@ public:
 		return h;
 	}
 
-	void operator()(Args&... _args)
+	void operator()(Args const&... _args)
 	{
-		for (auto const& f: m_fire)
-			if (auto h = f.second.lock())
-				h->fire(std::forward<Args>(_args)...);
+		for (auto const& f: valuesOf(m_fire))
+			if (auto h = f.lock())
+				h->fire(_args...);
 	}
 
 private: