On Monday, November 24, 2014 22:12:08 Eric via Digitalmars-d-learn wrote: > > @safe > class Y { } > > @safe > class X { } > > @safe > class Z > { > int x; > > this() > { > if (typeid(X) == typeid(Y)) x = 1; // Compile Error > else x = 2; > } > } > > void main() { new Z; } > > // test.d(19): Error: safe function 'test.Z.this' > // cannot call system function 'object.opEquals' > > Isn't this analagous to saying that the "instanceof" operator > in java endangers the GC? > > Is it correct to replace '==' with 'is'?
It's not that it's inherently unsafe. The problem is a combination of the fact that stuff in druntime that pre-existed @safe hasn't been made @safe yet (particularly, stuff in TypeInfo) and the fact that Object shouldn't even have opEquals, opCmp, toHash, or toString on it, because that restricts which attributes can be used ( https://issues.dlang.org/show_bug.cgi?id=9769 ), though I think that with @safe, we can work around that (unlike with const). However, for whatever reason, TypeInfo's opEquals function hasn't been marked with @safe or @trusted, so it's considered @system. That will need to be fixed, but I don't know if there are any implementation issues preventing it. It _looks_ like it could probably be marked @trusted, but I haven't actually dug into it in detail. In any case, you should be able to just mark the constructor as @trusted for now to work around the issue, and at some point in the future opEqualso or TypeInfo should be @trusted or @safe. - Jonathan M Davis