Problem with aggregate initialization of std::string

Created by: mattiasm83

There seems to be a problem with aggregate initialization of std::string.

The variables b and c in the code below uses this:

std::string a = mqttConf[F("server")];
std::string b = {mqttConf[F("server")]};
std::string c{mqttConf[F("server")]};

Serial.println("----");
Serial.println(a.c_str());
Serial.println(b.c_str());
Serial.println(c.c_str());
Serial.println("----");

The output of the following code shows this:

----
192.168.1.1


----

Only the first initialization works.

If I use explicit casts to std::string on the aggregate intializations, like this:

std::string a = mqttConf[F("server")];
std::string b = {mqttConf[F("server")].as<std::string>()};
std::string c{mqttConf[F("server")].as<std::string>()};

then the output shows this (the expected output):

----
192.168.1.1
192.168.1.1
192.168.1.1
----

It this a known limitation, or is it a bug?