Re: [Issue 6652] New: foreach parameter with number range is always ref
foreach parameter with number range is always ref I noticed this by getting into infinite loops. But that, more than anything, hints of very bad programming style. :)
[Issue 6652] New: foreach parameter with number range is always ref
http://d.puremagic.com/issues/show_bug.cgi?id=6652
Summary: foreach parameter with number range is always ref
Product: D
Version: D2
Platform: Other
OS/Version: FreeBSD
Status: NEW
Severity: normal
Priority: P2
Component: DMD
AssignedTo: nob...@puremagic.com
ReportedBy: d...@dawgfoto.de
--- Comment #0 from d...@dawgfoto.de 2011-09-12 10:19:15 PDT ---
void main() {
size_t cnt;
foreach(ulong n; 0 .. 10)
{
++n;
++cnt;
}
assert(cnt == 10);
cnt = 0;
foreach(ref ulong n; 0 .. 10)
{
++n;
++cnt;
}
assert(cnt == 5);
}
---
As this is rewritten in terms of a for loop all writes to n will
alter the loop.
A hidden copy of n is needed for non-ref parameters to match the range
foreach semantic.
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