[Issue 18172] std.getopt should allow taking parameters by `ref` (like std.format.formattedRead), s.t. it can be used in @safe

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18172

--- Comment #5 from Jonathan M Davis <issues.dlang at jmdavisProg.com> ---
You have to compile with -dip1000, which Phobos isn't right now. If I try it
locally with -dip1000, I get

q.d(10): Error: scope variable f assigned to non-scope parameter _param_3
calling std.getopt.getopt!(string, string, bool*, string, string, bool*).getopt
q.d(11): Error: scope variable b assigned to non-scope parameter _param_6
calling std.getopt.getopt!(string, string, bool*, string, string, bool*).getopt

and I get a similar error if I take the address when passing to getopt like you
normally would. getopt itself probably needs to have the parameters marked with
scope to fix that. Regardless, it seems to me that either it's possible to
tweak getopt to make this work with @safe in -dip1000, or it should be
discussed with Walter how to improve DIP 1000 to make it work. Conceptually, I
don't see any reason why getopt couldn't be made to work with scope and
-dip1000 in @safe, because it doesn't escape the pointers. The question is what
needs to be done to make it work.

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