Disabling copy constructor in shared structs

Artur Skawina art.08.09 at gmail.com
Mon Feb 13 05:38:01 PST 2012

Using "@disable this(this);" in structs marked as "shared" does not appear to be
possible; "shared" alone works, just "@disable this(this);" works too, but both
together result in compile failures with cryptic error messages about 'this', like
wrong type. not mutable or not an lvalue, usually without even mentioning any line
number. Defining a real postblit breaks too; commenting the 'this(this)' out makes
the code work again, but i'd like to prevent "auto s2 = s1" from working, as this
is obviously not a good idea for opaque shared structures which should only be
accessible via getter and setters.
Simple example, which gives a different error than the real code, but has a similar
problem; this program compiles only when one of the lines marked with '*' is
commented out:

shared                  // *
struct S(T) {
   T i;
   @disable this(this); // *

auto s1 = S!int(42);
void main() {
   //auto s2 = s1;

Known bug?


[and yes, "this(shared this) shared" etc will compile - but won't prevent the copy
 (will not be called at all)]

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