I'm giving Visual Studio Code (VSC) a try and am getting unexpected results. I have a program (sketch) that compiles fine in the Arduino IDE. I create a workspace in VSC, initialize the project, and after some more mucking about I get a compile there appears to succeed:
[Done] Finished verify sketch - RanchMonitor2.ino
But the console pane shows four "problems":
How can the compilation have succeeded if there are problems?
The same sort of thing is happening with one of the samples - HelloServer.ino In this case the problems are an incomplete type and memcpy_P not defined.
I wouldn't think it should make a difference, but I'm working without a board physically attached to the USB port.
UPDATE: I think "Problems" are issues identified by Intellisense. They appear even before a compilation is attempted. All I have to do is open the workspace and wait a few seconds, then the "problems" appear. Hence my conjecture they are Intellisense warnings, not compilation errors. Adding "ESP8266" to the Defines section of c_cpp_properties.json got rid of the error "WiFiManager" is undefined.