Re: why is ifThrown un@safe?

[bauss via Digitalmars-d-learn]

On Friday, 15 March 2019 at 18:04:05 UTC, Bastiaan Veelo wrote:

In the code below (https://run.dlang.io/is/d0oTNi), ifThrown is inferred as un@safe. If instead I write the implementation of ifThrown out (after res2) then it is @safe. As far as I can see, there is no real difference. So why doesn't ifThrown work in this case, and can it be made to work?

Thanks!

void main() @safe
{
    import std.process;
    import std.exception;

const res1 = execute(["clang", "-v", "-xc++", "/dev/null", "-fsyntax-only"], ["LANG": "C"])

        .ifThrown((e) @safe {
            import std.typecons : Tuple;

return Tuple!(int, "status", string, "output")(-1, e.msg);

        }); // Fails

    const res2 = () {
        try
        {

return execute(["clang", "-v", "-xc++", "/dev/null", "-fsyntax-only"], ["LANG": "C"]);

        }
        catch (Exception e)
        {
            import std.typecons : Tuple;

return Tuple!(int, "status", string, "output")(-1, e.msg);

        }
    }();
}

Because the handlers may be unsafe.

There is no safe overload of ifThrown.

However you can work around this using @trusted.