D-Programming-Language/phobos — pull request #1520 by tom-tan (2013-08-25 14:02:40+00:00)
Title: Make std.string.removechars @safe and pure

In `removechars`, `r` is newly allocated array. So it can be safe to cast it to the string type.
I use a trusted nested function instead of trusted lambda call because of the performance issue.