parallel foreach hangs

[Daniel Kozak via Digitalmars-d-learn]

this code never end

import std.stdio;
import std.file;
import std.parallelism : parallel;
import std.algorithm : filter;
void main(string[] args)
{
    foreach(d; parallel(args[1 .. $], 1))
    {
        auto phpFiles = 
filter!`endsWith(a.name,".php")`(dirEntries(d,SpanMode.depth));
        writeln(phpFiles);
    }
}