It can inline library functions, since, at latest, 1.4.2 (this is just what I happened to have handy on this computer). It's pretty easy to test by writing a pa

It can inline library functions, since, at latest, 1.4.2 (this is just what I happened to have handy on this computer). It's pretty easy to test by writing a package containing a simple function like "func Square(x int) int { return x * x }", compiling a main package that imports that package and calls Square, and then disassembling the executable to see whether it calls Square or inlines it.