Using dmd 2.066.0-rc1

Test with the following code:
-- splittest.d --
import std.stdio : writeln;
import std.array : split;

void main()
{
  writeln("one,two,three".split(","));
}
 -- splittest.d --

Compiled with 'rdmd splittest.d' outputs ["one", "two", "three"] as expected.
Compiled with 'rdmd -inline -O splittest.d' outputs ["one,two,three"], an array with one element instead of three.

It is the combination of the -inline and -O flags that causes the issue, on their own it works.

Works fine in dmd 2.065.