The code:

    enum f = "foo";
    enum s0 = f.replace("oo", "bar");
    enum s1 = f.replace("fo", "bar");

...results in:

    /usr/include/d/dmd/phobos/std/array.d(2054): Error: pointer cast from char[] to char* is not supported at compile time
    Segmentation fault

...under DMD64 2.058 on Linux.

It seems to segfault while appending new characters only when replacing the begining of a string at compile time. Replacing anything else works just fine.