On Wednesday, 10 May 2017 at 09:42:53 UTC, Timon Gehr wrote:
On 09.05.2017 23:56, Timon Gehr wrote:
core.exception.AssertError@ddmd/blockexit.d(90): Assertion
failure
----------------
...
Thanks! (It's a known issue though:
https://github.com/tgehr/dmd/blob/static-foreach/test_staticforeach.d#L330.)
Actually, yours is a different case with the same outcome (f
and idonotexist do not matter at all, the issue exists even for
static foreach(j;0..0){}).
All static foreach loops over empty (non-AliasSeq) aggregates
failed that assertion. The reason was that CTFE can return a
null literal from a function that returns T[], but the constant
folder cannot actually evaluate null.length for some reason.
So here is the difference between null and []:
null :
() { Slice* s; s = null; return s; }
[] :
() { Slice* s; s = alloca(sizeof(*s)); s.base = null; s.length =
0; return s; }
Therefore
null.length => (cast(Slice*)null).length; which results in a
segfault.
and
[].length => (cast(Slice*)somevalidSliceDiscriptor).length;
