On Wed, Aug 29, 2018 at 07:02:42PM +0000, Dave Jones via Digitalmars-d wrote: > On Wednesday, 29 August 2018 at 18:02:16 UTC, Timon Gehr wrote: > > On 29.08.2018 19:15, H. S. Teoh wrote: > > > On Wed, Aug 29, 2018 at 06:58:16PM +0200, Timon Gehr via > > > Digitalmars-d wrote: > > > > On 28.08.2018 19:02, H. S. Teoh wrote: > > > > > On Tue, Aug 28, 2018 at 08:18:57AM +0000, Eugene Wissner via > > > > > Digitalmars-d wrote: > > > > > > Currently, immutable implicitly converts to const. If const is > > > allowed to be overridden, then you could violate immutable, which > > > is UB. ... > > > > __mutable fields are __mutable also in the immutable instance. You > > might get into trouble with shared if you are not careful because of > > the unfortunate "implicit shared" semantics of immutable, but it is > > up to the programmer to get this right. > > So you cant cast away const but you can specify a field stays mutable > even if the aggregate is const or immutable?
That appears to be the case. But it scares me that const(T) would no longer guarantee you can't modify anything in T. I fear it will break some subtle assumptions about how const/immutable works, and introduce hidden bugs to existing code. T -- Doubt is a self-fulfilling prophecy.
