Slightly reduced test case:

-------------------------------------

import std.array : staticArray;

@nogc void main()
{
    auto arr = ["foo"].staticArray;
}

-------------------------------------

Compiled with DMD32 D Compiler v2.090.0-dirty:

dmd -m64 test.d     
Assertion failure: 'e && retregs' on line 1862 in file 'C:\Users\vagrant\clones\dmd\src\dmd\backend\cod1.d'

Without Phobos:

void main() @nogc
{
    auto arr = ["foo"].staticArray;
}

string[1] staticArray(string[1] a) @nogc
{
    return a;
}

Closing because the assertion failure does not occur with current master