On Friday, 8 April 2016 at 01:36:18 UTC, rcorre wrote:
@nogc unittest {
int[2] a = [1, 2];
assert(a == [1, 2]); // OK
immutable(int)[2] b = [1, 2];
assert(b == [1, 2]); // fail: array literal may cause
allocation
}
Is there any logic behind allowing the comparison with `a` but
not `b`, or is this a compiler bug?
Semantically, array literals are always allocated on the heap. In
this case, the optimizer can obviously place the array on the
stack or even make it static/global. However, it would be in poor
design to rely on the optimizer to satisfy @nogc. It comes down
to portability; if the code compiles successfully with one
compiler, then it should compile successfully in any other
compiler.
Also, the way that compilers are typically built is that semantic
analysis is done in the frontend and optimization is done in the
backend. Trying to build a bridge between these two would be
incredibly difficult and make implementing the compiler much more
complex with little gain.
